How well can a human-generated "random number" be predicted?

It seems like there is a fairly big literature on this topic.

Wagenaar (1972) provides an early review of research. The author summarises around 15 studies. The studies involved generated random elements including letters and numbers of varying lengths. In all but one study, participants were deemed to be not good at randomising. As part of their review they talk about various forms of nonrandomness and factors that increased the nonrandomness (e.g., naivity of subjects regarding types of randomness, boredom, presence of a natural order to the objects, etc.). In general participants either engaged in too much alternation or too many runs of the same response. Wagenaar (1972) noted the need for more research. The general model seemed to be one whereby stable individual differences (e.g., memory, skill, and mental representations of randomness), states (e.g., boredom, fatigue), and inherent constraints on human randomness generation interacted to influence the degree of randomness produced.

Towse and Neil (1998) provide software call RgCalc for evaluating randomness in human generated sequences.

Brugger (1997) provides a more recent review, summarising:

  It is conjectured that Tune's explanation of sequential nonrandomness
  in terms of a limited capacity of short-term memory can no longer be
  maintained. Rather, interdependence among consecutive choices is
  considered a consequence of an organism's natural susceptibility to
  interference. Random generation is thus a complex action which demands
  complete suppression of any rule-governed behavior.

I also found a couple of articles by Persaud (2005) and Figurska et al (2008) that might be relevant.

Summary: Humans typically display some form of nonrandomness when generating sequences of digits. The degree of this nonrandomness varies across people. It is unclear to me at this point how well individuals could perform, for example, if they had an aptitude for random number generation or were trained to generate random numbers. For example, individuals might be able to draw on cues in the external world that are random and use that as their own personal input for generating responses (but perhaps this would be considered cheating).

However, the nonrandomness may only enable very small incremental prediction above chance in predicting any given response. Furthermore, presumably longer initial sequences of response would improve the ability to guess the subsequent response. Having longer sequences would allow you to extract the form of nonrandomness that the particular individual adopts (e.g., do they prefer alternating numbers or runs, do they prefer some digits over others, are there sequences of numbers preferred).

References

Brugger, P. (1997). Variables that influence the generation of random sequences: An update. Perceptual and Motor Skills, 84(2), 627-661.
Figurska, M., Stańczyk, M., & Kulesza, K. (2008). Humans cannot consciously generate random numbers sequences: Polemic study. Medical hypotheses, 70(1), 182-185.
Persaud, N. (2005). Humans can consciously generate random number sequences: A possible test for artificial intelligence. Medical hypotheses, 65(2), 211-214.
Towse, J. N., & Neil, D. (1998). Analyzing human random generation behavior: A review of methods used and a computer program for describing performance. Behavior Research Methods, Instruments, & Computers, 30(4), 583-591.
Wagenaar, W. A. (1972). Generation of random sequences by human subjects: A critical survey of literature. Psychological Bulletin, 77(1), 65-72.


Why does a person temporarily go blind without any apparent cause?

Loss of sensory or motor functioning are possible symptoms of a conversion disorder.

Conversion disorders usually appear during adolescence and are mostly caused by situations of extreme stress (such as the frontline experience of soldiers). Often the disorders enable the patient to avoid specific tasks or responsibilities or recieve the attention of specific persons.

It is important to make sure that the symptoms are not caused by neurological disorders, such as an illness of the central nervous system. Most paralyses and sensory impairments have neurological causes and many are mis-diagnosed as conversion disorders.


Seeking a standard term for the "Where's Waldo?" effect

Learned recognition

The evolution of signal form: effects of learned versus inherited recognition (The Royal Society Publishing)

  Organisms can learn by individual experience to recognize relevant
  stimuli in the environment or they can genetically inherit this
  ability from their parents...We analyse the joint effects of receiver
  biases, signal cost and mode of acquisition, investigating the
  circumstances under which learned recognition gives rise to more
  exaggerated signals than inherited recognition.

Curse of knowledge

Your quote:

  Usually after learning one of these things, one tends to underestimate
  its difficulty for someone who hasn't solved it.


Is "Schizophrenic" considered to be a derogatory or offensive term?

You never know what's gonna offend someone...That being said, "hallucinations in people with schizophrenia" does seem the safer option, but "schizophrenics" (not capitalized) is used plenty often. Here's an interesting Google result:

  Schizophrenics Anonymous (SA) is a self-help group for persons who have schizophrenia or a schizophrenia-related illness.

I don't see them using "schizophrenics" outside of the title though, which further supports the use of "persons / people with schizophrenia". This follows a general guideline: one should avoid defining people by their afflictions and emphasize their personhood foremost. It might seem trivial with occasional use, but conflating a condition with an object category (person) might affect perception of those people, including their self-perceptions / identities, since these are largely matters of emphasis already.
(This is armchair theorizing without references...or any arms on the chair...Please edit or comment with any support or disagreement.)


Why is the initial first-line response to a psychological problem not a brain scan?

The first stop when a non-emergency medical issue evolves is, as you say, a visit to the GP. This is not a supplement to diagnosis. Instead, a visit to the GP can be a critical step in the treatment process and a GP will assess what the most probable underlying cause is during a consultation, based on a physical examination and verbal communications. Then the GP can refer the patient to the proper next medical practitioner for specialized help. Note that a diagnosis involves mainly excluding other causes and narrowing down the list of options.

Your case report lacks some critical information (e.g., age at diagnosis etc.), but the statistics behind the diagnosis can still tell a lot about the GPs decision:

The incidence of brain tumors is about 22 cases per 100,000 individuals (0.02%). Brain tumors are most likely to arise in kids or late teens. Dependent on the age of your friend at the time of diagnosis, this may have placed them out of that age window.
The incidence of visual hallucinations is about 17 per 1000 (1.7%) (Tien, 1991), i.e., orders of magnitude higher than brain tumors. In other words, just a minor fraction of visual hallucinations are caused by brain tumors. A more likely cause for hallucinations are positive psychotic symptoms, the realm of psychotherapists and psychiatrists. Most visual hallucinations are caused by psychosis (e.g., schizophrenia), Parkinson's disease and Alzheimer's disease (source: WebMD). The latter two are typical cheriatric diseases (diseases linked to old age). If your friend was not considered an elderly at the time of diagnosis, it would make psychosis the most likely candidate cause of the symptoms.

Brain scans do not diagnose Alzheimer's or Parkinson's, nor psychosis. A brain scan would only, perhaps, find a tumor that has a very small chance of occurring. Moreover, a single scan may not be enough. The tumor may be small and clinical tests, fMRI, PET, or bone scans may be necessary (source: JHMI), which can result in an extensive list of scans, many hospital visits, and associated financial burden. The GP chose the best hit, and that's a psychiatric issue.

Reference
- Tien, Soc Psychiatry Psychiatr Epidemiol (1991); 26(6):287-92


Why some people feel their skin itching when they're told about insects and no insects happen to be nearby?

The name you are looking for is Formication.

  Formication is the medical term for a sensation that exactly resembles that of small insects crawling on (or under) the skin. It is one specific form of a set of sensations known as paresthesias, which also include the more common prickling, tingling sensation known as "pins and needles". Formication is a well documented symptom, which has numerous possible causes.


How would the blind experience a hallucinogen like LSD?

Short answer
Based on a dated and small study, early-blind individuals do not experience drug-induced hallucinations, while the late-blind can, but not necessarily do so.

Background
Krill et al. (1963) investigated the effects of LSD on totally blind people (i.e., no residual vision) and they report visual hallucinations in 13 out of 24 subjects. This study shortly reviews three other studies in this field (LSD and mescalin administered to blind people) and the consensus the authors reach is that blind folks do experience visual hallucinations.

However, as @JoeBathelt very rightfully notes, it is important to acknowledge the difference between congenitally blind and late blind people that lost vision later in life. Late-blind individuals often experience visual imagery, while congenitally blind do not and cannot. In the Krill et al. study linked, they included four congenitally blind subjects. The remainder were acquired blind that had lost their eye sight later in life. The congenitally blind group had lost their vision at, or before the age of two (which I would call early blind, but that's debatable). None of these 4 subjects experienced hallucinations. Given that half of their study group experienced hallucinations, one would expect two of these four to have experienced hallucinations. Although the congenitally (i.e., early-blind) group was small, it leads me hence to believe that prior visual experience at least early in life is a prerequisite for visual hallucinations to occur. However, not many studies have been published on the topic and I am most curious to see more answers to this most interesting question.

Reference
- Krill et al., Arch Ophthal (1963); 6: 180-5


I think Keegan provides a great set of references, but I just wanted to expand on his answer in a little bit more detail. Penrose and Hameroff's ideas are mentioned a lot on the internet and although they are often debunked, you can never do it enough. I want to discuss (1) what microtubules are and (2) are there quantum effects in them? And, more importantly, (3) does that even matter? and (4) is any of this new?
What are microtubules?
Microtubules are a structure in the cytoskeleton that are found in all dividing eukaryotic cells and in most differentiated cell types (Desai & Mitchison, 1997). They are by no means exclusive to neurons, so if you think they bestow consciousness then you have to grant consciousness to all eukaryotes (something that most philosophers would find strange), or you are back at the same difficulty as before in trying to explain how networks of microtubules give rise to consciousness and thus postulating them as your basic units instead of neurons gives you no explanatory power.
Related discussions:
Which organisms have the neuroanatomy Roger Penrose supposes play a role in consciousness?.
Are there quantum effects in microtubules?
In the video, Hameroff describes quantum and classic effects as a ying-and-yang. This is a very misleading picture, for a physicist the world is fundamentally quantum but at large sizes, and high temperatures (i.e. a lot of interaction with an external environment) is well described by our more intuitive laws of classical physics. Thus, the question isn't are there quantum effects, but are the quantum effects significant enough to cause non-classical consequences? Note, that most of chemistry can't be properly explained by classical physics, so every chemical reaction needs quantum effects to make sense, but we don't suggest that this makes every chemical reaction conscious.
The exciting part is that quantum effects do matter in (a non-trivial way) in some biological systems; most notably in photosynthesis (Engel et al, 2007). In particular, a certain energy perturbation after a photon is absorbed follows a quantum random walk, and one could speculate that this can be used for quantum computing, but there is no reason to expect it.
Microtubules are small enough to not completely rule out quantum effects. They are rope like polymers that grow to a length of about 25 micrometers (25000 nm), and have an outer-diameter of around 25 nm or about 200 atoms across. Researchers commonly use quantum dots to play with quantum effects, and these are typically spheres on the order of 10 to 50 atoms in diameter. Note, that we don't know how to couple 5000 quantum dots in one coherent chain (how many you would need to get the length of a microtubule).
However, the issue physicists usually raise, is not one of size but of the time that the microtubule would need to maintain coherence (i.e. a pure quantum state). The reason photosynthesis uses a quantum random walk, is because a classical one would not be fast enough to find a binding site. Thus, in that case the timescales involved are miniscule. The timescales involved in the function of microtubules are much longer, and physicists believe that their state is not coherence for that length of time (Tegmark, 2000).
Even if microtubules are quantum, so what?
This is the real clincher, suppose quantum effects are important to microtubules. Suppose that whole networks of microtubules are able to keep coherent entanglement between. Heck, suppose that the brain is a giant quantum computer. So what?
For a lot of people (like Hameroff), there is this misconception that classical physics does not allow for free well but quantum mechanics does because of wave function collapse. Thankfully, we have Conway & Kochen's (2006) free will theorem which says (more or less), any free will you give to an observer/experimenter in your philosophy of quantum mechanics, you will also have to give that some amount of agency to electrons and other subatomic particles. In other words, if your interpretation of quantum mechanics somehow gives you free-will then it is a trivial kind of free will that every particle in the universe has. Of course, this argument can be explored in much more depth, but I suggest reading someone that is familiar with quantum computing (Aaronson, 2013) instead of Hameroff.
For Penrose (see The Emperor's New Mind) consciousness is non-algorithmic and he suggests that a magical quantum computer could do these non-algorithmic tasks. The reason I use 'magical' is because a real quantum computer is Turing-complete, if a classical computer cannot solve a problem then neither can a quantum one (of course, if a classical computer can solve a problem, then quantum one can as well and might be able to do it qualitatively faster). For a nice computer science debunking of this part of Penrose's argument take a look a Scott Aaronson's lecture notes.
Is any of this even new?
For me, the most disappointing part of this pseudoscience is its lack of novelty. The basic philosophical urge underlying Hameroff's speculation is an over-application of reductionism: consciousness can't be something emergent, there has to be a basic essence to it. Since he can't take the dualist stance of Descartes, he instead postulates that it is"quantum magic". Even this use of quantum magic isn't original—it was an extremely popular type of hokum in the 70s that has been called quantum mysticism.
Related discussion:
What makes people easily subscribe to pseudoscientific theories?
References
Aaronson, S. (2013). The Ghost in the Quantum Turing Machine. arXiv preprint arXiv:1306.0159.
Conway, J., & Kochen, S. (2006). The Free Will Theorem. Foundations of Physics, 36(10): 1441–1473.
Desai, A., & Mitchison, T. J. (1997). Microtubule polymerization dynamics. Annual Review of Cell and Developmental Biology, 13(1): 83–117.
Engel GS, Calhoun TR, Read EL, Ahn TK, Mancal T, Cheng YC et al. (2007). Evidence for wavelike energy transfer through quantum coherence in photosynthetic systems. Nature, 446(7137): 782–6.
Tegmark, M. (2000). Importance of quantum decoherence in brain processes. Physical Review E, 61(4): 4194–4206.


How can I design a staircase function that converges on a given hit-rate?

If n != m then it will not home in on the 50 % threshold. In these simple N-up/N-down staircases, you can modify either the stepsize (as you proposed) or the number of successes/failures to act as a criterion for upgrade/downgrade.

A comprehensive introduction to these staircases and the effect of changing these properties can be found in this paper. The 80 % threshold is simple because it's simply nDown=1 and nUp=3 with the same stepsize in either direction.

Several staircase methods are implemented in the PsychoPy python package/software and it actually has the nDown=1 and nUp=3 as default value if you don't specify anything else.

Note: If you can assume a nice mathematical relationship between stimulus parameter and perception (i.e. linear, logistic, power etc.), then it'll probably be more efficient to use regression because even though your parameter is way off the desired threshold, it's still informative about the mathematical relationship. Thus you can use it to infer where the threshold should be and home in much more efficiently than the "scanning-like" approach of N-up/N-down methods.


Summary:
It's worth noting that all languages have an oral origin so concerning the biological origins of grammar we must look for neurological structures involved in speech processing/production. However, it's worth first clarifying Chomsky's view that there are two levels of innateness: at the level of genetics i.e. biological heredity and at the level of neurological structures i.e. morphology and morphogenesis.
Based on the available evidence, it appears that specific genes and neurological structures that aid language acquisition do exist but these aren't necessarily specific for language.
 Chomsky's view:
Chomsky has historically held firm to the view expressed in 1983 [1]:

QUESTION: Is the role of heredity as important for language as it is
for embryology?
CHOMSKY: I think so. You have to laugh at claims that heredity plays
no significant role in language learning because exactly the same kind
of genetic arguments hold for language learning as hold for
embryological development. I’m very much interested in embryology but
I’ve got just a layman’s knowledge of it. I think that recent work,
primarily in molecular biology, however, is seeking to discover the
ways that genes regulate embryological development. The gene-control
problem is conceptually similar to the problem of accounting for
language growth. In fact, language development really ought to be
called language growth because the language organ grows like any other
body organ.

However, Chomsky also recognised that there was little neurobiological evidence to support this view at the time beyond reasonable hunches:

QUESTION: Is there a special place in the brain and a particular kind
of neurological structure that comprises the language organ?
CHOMSKY: Little enough is known about cognitive systems and their
neurological basis; so caution is necessary in making any direct
claims. But it does seem that the representation and use of language
involve specific neural structures, though their nature is not well
understood.

Chomsky's particular hypotheses:
From the above interview we may derive two hypotheses:

That there might be genes for linguistic ability.
That the development of language may rely on neurological structures that are specific for language.

The first hypothesis is partially validated by research on the FOXP2 gene [3]. In 2001 it was found that in humans the mutation of this gene significantly disrupts speech and language skills.
That said, we must note that FOXP2 has other roles:

...FOXP2 is also expressed in defined regions of other tissues during
embryo development, including the lung, the gut and the heart, as
well as in several tissues of the adult organism.

Given that the heart, gut and lung developed prior to linguistic ability it's more likely that FOXP2 was initially useful for heart and lung function, and was exploited for linguistic ability rather than the other way around. This gene is actually present in other animals. The authors of [3] clarify this point:

the presence of FOXP2 in other animals does not diminish its relevance
for speech and language, but rather represents another example of
recruitment and modification of existing pathways in evolution.

The possibility of specific neurological structures:
Regarding the second hypothesis, this is the subject of ongoing investigation that combines AI research, cognitive science, neuroscience and morphogenesis. How language develops is a very complex and fascinating subject.
In a pioneering robot experiment [2], the linguist and cognitive scientist, Pierre-Yves Oudeyer showed that with basic neural equipment for adaptive holistic vocal imitation, coupling directly motor and perceptual representations in the brain, it was possible to generate spontaneously shared combinatorial systems of
vocalizations in a society of babbling individuals:

...the transition from inarticulated vocalization systems to
human-like speech codes may have been largely due to a modest
biological innovation. Indeed, the model indicates that neuronal
structures that encode a priori and specifically phonemic
organization, as well as typical regularities of speech, do not need
to be innately generated to allow the formation of such speech code.
This is the second contribution of this work: it allows us to
understand how the self-organizing properties of simple neural
structures may have constrained the space of biological vocalization
structures and how speech codes may have been generated and selected
during phylogenesis. These new hypothesis may not have been identified
without the use of computer models and simulations, because the
underlying dynamics are complex and difficult to anticipate through
uniquely verbal reasoning. This illustrates the potential importance
of these new methodological tools in human and biological sciences.

Pierre-Yves' research on robot languages suggests that:

The specific neurological structures that aid acquisition aren't necessarily specific for language.
Cognitive scientists should investigate the development of the vocal tract during language acquisition.

Concerning specific neurological structures, today we know that Broca's area is heavily used for speech production but similar regions are present in other apes that have limited linguistic ability [6]. So it's important to consider the causal influence of Broca's region within cortical networks involved in speech production. In [7] the authors share that:

Using direct cortical surface recordings in neurosurgical patients, we
studied the evolution of activity in cortical neuronal populations, as
well as the Granger causal interactions between them. We found that,
during the cued production of words, a temporal cascade of neural
activity proceeds from sensory representations of words in temporal
cortex to their corresponding articulatory gestures in motor cortex.
Broca’s area mediates this cascade through reciprocal interactions
with temporal and frontal motor regions.

For this reason in the discussion section they infer:

...Broca’s area is not the seat of articulation per se, but rather is
a key node in manipulating and forwarding neural information across
large-scale cortical networks responsible for key components of speech
production.

So far there is a lot of neurological evidence supporting Oudeyer's conjecture that specific neurological structures that aid acquisition aren't necessarily specific for language. As for Oudeyer's second suggestion there's still a lot we don't know. You might be interested in the work of the Max Planck Department for the Neurobiology of Language[4,5].
 References:

Noam Chomsky. Things No Amount of Learning Can Teach. Interviewed by John Gliedman. 1983.
Pierre-Yves Oudeyer. Self-Organization and Complex Dynamical Systems
in the Evolution of Speech. 2013.
Gary F. Marcus and Simon E. Fisher. FOXP2 in focus: what can genes tell us about speech and language? Elsevier. 2003.
Hagoort, P., & Beckmann, C. F. (in press). Key issues and future directions: the neural architecture for language. In P. Hagoort (Ed.), Human Language: From Genes and Brains to Behavior. Cambridge, MA: MIT Press.
Hagoort, P. (in press). Introduction. In P. Hagoort (Ed.), Human Language: From Genes and Brains to Behavior. Cambridge, MA: MIT Press.
Claudio Cantalupo and William D. Hopkins. Asymmetric Broca’s area in great apes. NIH Public Access. 2001.
Adeen Flinker, Anna Korzeniewska, Avgusta Y. Shestyuk, Piotr J. Franaszczuk, Nina F. Dronkers, Robert T. Knight, and Nathan E. Crone. Redefining the role of Broca’s area in speech. PNAS. 2015.


Is there a term for not recognizing that other people think differently, or projecting your thought patterns on others?

Interesting question!

Theory of mind is the ability to attribute mental states, motivations, etc. to others and recognize that others have separate intentions, states, and motivations from his or her own.

The specific phenomenon that you are describing may stem from this concept called naive realism, or the idea that we see the world as it truly is, and that others share the same perceptions as we do. There are several other social biases that stem from the notion of naive realism. You might be particularly interested in
the false-consensus effect, or the tendency to overestimate how many people share our beliefs. There is also attribution bias, or the tendency to interpret events in light of our own social world when trying to find reasons for the behavior of others.

Here are four studies that might be of interest to you, from a paper on the false-consensus effect and self-serving bias. As these are biases primarily from the realm of social psychology, most studies you find will be of groups and in-group biases. It might be more helpful to look for specific personality traits that may describe the phenomenon, i.e. lack of self-awareness.

You might also be interested in self-perception theory and, by extension, the truce experiment.


EEG systems are quite expensive and are far out of the budget you have outlined. There are four points to be made on this matter:

The most basic "set" I could find produced by Biosemi costs $11,000 and this set doesn't include the caps and bands (electrodes) required for collecting data.
It is also important that the location of this system be in a soundproof and electromagnetic safe room to ensure there is little interference in data collection.
There is quite a lot of training required to properly conduct an EEG study and to test participants in a safe and ethical manner.
Analyzing raw EEG data is also not a simple feat. The level of statistics understanding and software knowledge required for this type of analysis is not usually obtained until graduate-level studies.

As an aside, I am not sure that the question you have is worth the resources needed to test via EEG. For high school level research it would be best to conduct a behavioural study to measure the effects of lavender oil inhalation on anxiety symptoms. There are many available behavioural measures of anxiety that have been tried and tested in the scientific community. It is standard practice to begin with behavioural measures before moving to physiological measures.

Please note, there is great value in replicating studies. The scientific community often feels pressured to produce novel findings, as new and exciting results may lead to fame and a bigger pay cheque. It is paramount to scientific progress to replicate previous findings as often times novel findings are never replicated and therefore never subjected to "fact checking" (and could therefore not be replicable in the first place,  fluke findings do occur). Progress can only be made if we are constantly questioning what we think is right. It would be advisable for a high school level researcher to find a study related to the topic you are interested in and to replicate the methods used in that study in an attempt to find the same results as the original authors. Not only would this be more accessible to you at this level of education, but it will teach you valuable research skills and help improve your understanding of the questions you have.


Are there any pain scales which measure how much of the body is in pain?

I can tell you this, in RA the addition of swollen joints in a flair up increases the pain until your number exceeds so many than the pain levels. In arthritis of the spine, spondylosis seams to stay the same as the gradual increase of more arthritic vertebra increases. But when spondyolithisis increased from one to two the pain was double. (The movement forward or sideways of the vertebra) That's all I know,10 years experience.


What can cognitive psychology tell us about the results of the Stanford Prison Experiment?

I've always thought of Stanford Prison Experiment (and Abu Ghraib) as a situation in which group think forms a sort of feedback loop. If you agree that people behave within context of a group, and the context is created by the group itself (Hogg, 1998), then you can see what is happening. The context may at first be in line with the larger group (the University, or Military, or American culture in general). Within the smaller group however, individuals may "push the limit" of acceptable behavior. But in doing so, they are changing to context of the group. For a person to "push the limit" again, would be to act in an even more extreme way. The situation feeds back upon itself.

The question remains, as you pointed out, what motivation starts this movement in the first place? There is no reason to think it couldn't feedback upon itself in the other direction, either. There is some underlying feeling that is amplified by this group think. In the Hogg article, the researches essentially seeded that motivation experimentally. But in a normal situation, it can be virtually anything. Intuitively, I would say in the prison experiment the initial seed was just a desire for the students to act out the roles they were given. Prisoners obey the guards. Each time the limit of acceptable behavior was pushed, the context that defined acceptable behavior was changed too.

Myers (1977) describes something similar, which he calls polarization. In his research, he showed a tendency for people to not only conform to the group standards, but also try to exceed them in, "the socially preferred direction". This phenomena, plus a tendency to act within the context of a group, can lead to runaway behavior.

References

http://psycnet.apa.org/journals/gdn/2/1/48/

http://www.sciencedirect.com/science/article/pii/0022103178900495


Terminology for introvert's frustration after excessive social exposure

This does not constitute a definitive answer, so I invite criticism and feedback.

I don't believe there is a specific term for this state, as energy management and the introversion/extroversion scale seem to be a somewhat recent area of focus. However, it seems reasonable to think that the feelings experienced by an over socialized introvert may be similar to experience of decision fatigue, which is when the quality of ones decisions worsen the more decisions they need to make.

Since socialization for introverts often requires more deliberate internal calculations than extroverts, decision fatigue and the experience you're seeking a name for might be cousins. As such, perhaps 'social fatigue' is a useful term.


Is there a term that describes the personality trait of always desiring more?

I'm not entirely sure what you mean by "renounce," but you may find some answers to your question in the fields of social psychology and behavioral economics. The first part of your question describes someone who is unwilling to commit or make a decision for fear of losing out on future opportunities. There has been research to indicate that having more options when making a decision is actually stressful and can provoke anxiety (Ackerman, Gross, & Celly, 2014).

One recent study found that individuals who were presented with all options at once were more satisfied than those who were shown options one at at time (Mogilner, Shiv, & Iyengar, 2013). The individuals who were given options one at a time tended to imagine a better, ideal option was yet to come; the authors noted that these participants were less happy with their choices in part because of that hope. The introduction to this paper references several other papers which found that individuals who were focused on possible options were less satisfied with the choices they may and were less likely to stick with those choices because of the hope for "something better." The paper specifically cites several articles which indicate that a person's commitment to their romantic partner is not necessarily influenced by the partner's characteristics, but by the person's focus on other options (Gange´ and Lydon 2001; Johnson and Rusbult 1989; Lydon et al. 1999; Rusbult, Martz, and Agnew 1998). Similarly, Miller (1997) found that awareness of and attention to alternative partners was the highest predictor of failure in romantic relationships.

How people approach decisions also impacts how they address the options presented. In choice deferral, a person puts off a decision that requires difficult compromises (such as committing to one partner and thus losing the freedom to continue dating) in order to avoid the negative emotions linked to that decision (Luce, 1998). Some people may be more prone to this behavior than others. Schwartz and colleagues (2002) have proposed that people fall into two groups: those who seek to maximize their decision by finding the very best option out of choices presented (maximizers), and those who have an idea in mind of what would be an "acceptable" option and settle for the first choice that surpasses their expectations (satisficers). Maximizers are always on the look out for "the best," are less satisfied with their choices, more likely to "socially compare" their options to others, and more likely to experience regret (Ma & Roese, 2014). Another recent publication proposed that when individuals experience "choice closure," and stop re-evaluating the non-selected alternative options, satisfaction with choice can increase (Gu, Botti, & Farro, 2013).

Again, I am not certain I understood all of your question, but I hope that this provides you with a starting point to find the answer.

Ackerman, D., Gross, B. L., & Celly, K. S. (2014). Having many choice options seems like a great idea, but...: Student perceptions about the level of choice for a project topic in a marketing course. Journal of Marketing Education. April, e-pub ahead of print. Doi: 10.1177/0273475314522038

Gagne, F. M., & Lydon, J. E. (2001). Mindset and relationship illusions: The moderating effects of domain specificity and relationship commitment. Personality and Social Psychology Bulletin, 27(9), 1144-1155.

Gu, Y., Botti, S., & Faro, D. (2013). Turning the page: The impact of choice closure on satisfaction. Journal of Consumer Research, 40(2), 268-283. DOI: 10.1086/670252

Johnson, D. J., & Rusbult, C. E. (1989). Resisting temptation: Devaluation of alternative partners as a means of maintaining commitment in close relationships. Journal of Personality and Social Psychology, 57(6), 967-980.

Luce, M. F. (1998). Choosing to avoid: Coping with negatively emotion-laden consumer decisions. Journal of Consumer Research, 24, 409-433.

Ma, J., & Roese, N. T. (2014). The maximizing mind-set. Journal of Consumer Research, 41(1), 71-92. DOI: 10.1086/674977

Miller, R. S. (1997). Inattentive and contented: Relationship commitment and attention to alternatives. Journal of Personality and Social Psychology, 37(4), 758-766.

Mogilner, C., Shiv, B., & Iyengar, S. S. (2013). Eternal quest for the best: Sequential (vs. simultaneous) option presentation undermines choice commitment. Journal Of Consumer Research, 39(6), 1300-1312. doi:10.1086/668534

Rusbult, C. E., Martz, J. M., & Agnew, C. R. (1998). The Investment Model Scale: Measuring commitment level, satisfaction level, quality of alternatives, and investment size. Personal Relationships, 5(4), 357-391.

Schwartz, B., Ward, A., Monterosso, J., Lyubomirsky, S., White, K., & Lehman, D. R. (2002). Maximizing versus satisficing: Happiness is a matter of choice. Journal Of Personality And Social Psychology, 83(5), 1178-1197. doi:10.1037/0022-3514.83.5.1178


Have the core CBT "Thinking Errors" been found to NOT be effective in evidence-based clinical practice?

I think you should change the question a little bit to "What should be done to the Thinking Errors?" or "Just identifying and evaluating Thinking Errors might not be effective?". Yes, they may not be effective. Please be careful that all mental problems need to be treated by professional therapist and a very important part of their expertise involves the diagnosis. There are many anxiety or depressive disorders that they manifest similar "Thinking Errors" kind of thinking, but they have different underlying causes and should be treated differently. It's not to say that strategies like those described in The Feeling Good Handbook don't work, rather they work when things are simple. If you feel that things are more complicated you should surely seek some professional advice.

To illustrate this point to you by an example I would like to mention Obsessive Compulsive Disorder (or OCD). In OCD, there are some problems in cognitive system that makes the person being constantly paralyzed by lots of Intrusive Thoughts. The content of these thoughts may be similar to "Thinking Errors" or could be corrected by similar strategies, but focusing on them and trying to correct them make them stronger, more sailient, and more frequent. People with this disorder then feel that they are compulsively correcting their erroneous thoughts, but it seems they can never get rid of them. For this disorder, another treatment strategy has been offered called Exposure and Response Prevention (EX/RP). In this kind of treatment people are encouraged to face their intrusive thoughts, but don't respond to them.To try to accept their presence and at the same time not to let them to make them do anything, or not do anything. There is abundant evidence that EX/RP is effective for OCD.

And there are also other disorders with their idiosyncrasy. I'm not sure what kind of problem you're describing, but if you want to use self-help method (with all it's pro and cons) you could take a look at diagnostic features of OCD.


Do people who lose their faith tend to replace it with other non-evidence-based reasoning?

This is an interesting question, so I'll take a stab at it.  Direct evidence for the claim is hard to come by.  Generally, religious affiliations, conversions, and loss of faith are self-identified in surveys.  The reliance on self-identification makes it difficult to test the claim that people move to some other non-evidence-based reasoning, as they may not be aware of it.  Indirect evidence is easier to find.

The extensive Religious Landscape Survey (2009) by the Pew Forum on Religion & Public Life for example, asks the self-identified "unaffiliated" who grew up religious to explain their reasons for leaving their faith.  Only about 40% leaving Christianity cite not believing in God as their reason, and less than 30% leaving Catholicism cite no longer being religious in some way.  Looking at specific survey responses, most converts leave their religion for reasons other than relying on science and logic, and remain "spiritual" in some way.

Another way to test the claim is to ask people about their beliefs, as is nicely summarized here, from the same survey.  A large proportion of non-religiously affiliated participants - even some self-identified atheists - believe in God, the afterlife, or some other type of spirituality.


The Neurological Engineering Framework does not explicitly state a mechanism for memory. There is no "hard-drive" in the brain for easy retrieval and access. Rather, memory is captured in the connection weights between neural populations and the dynamics of the network.

In the Hierarchical Reinforcement Learning example, linked to in the previous question, the "memory" of the map for the navigation task is saved by modifying the connections weights of the neurons representing the environment.

In the serial list memorisation task, the working memory for saving the semantic pointer list items is preserved in an integrator, which is essentially a neuron population that feeds back on itself.

These are examples of working memory, in other words, the memory that allows you to drive a car without really remembering how exactly you drove it. Long term memory modeling requires quite a few more mechanisms (memory reconsolidation) and structures (hippocampus, amygdala) that haven't been captured in any system built with the NEF yet.


Does law of attraction have psychological basis?

Ahh yes, The Secret. I'd recommend starting with Wikipedia for a critical view of the "law of attraction" and the book as a whole. The former page has some particularly good excerpts to offer (emphasis added; hyperlinks not preserved, though I'd appreciate help editing them back in):

Skeptical Inquirer magazine criticized the lack of falsifiability and testability of these claims.$^{[6]}$ Critics have asserted that the evidence provided is usually anecdotal and that, because of the self-selecting nature of the positive reports, as well as the subjective nature of any results, these reports are susceptible to confirmation bias and selection bias.$^{[18]}$ Physicist Ali Alousi, for instance, criticized it as unmeasurable and questioned the likelihood that thoughts can affect anything outside the head.$^{[1]}$
The Law of Attraction has been popularized in recent years by books and films such as The Secret...Writing for the Committee for Skeptical Inquiry, Mary Carmichael and Ben Radford wrote that "neither the film nor the book has any basis in scientific reality", and that its premise contains "an ugly flipside: if you have an accident or disease, it's your fault." $^{[6]}$
Others have questioned the references to modern scientific theory, and have maintained, for example, that the law of attraction misrepresents the electrical activity of brainwaves. $^{[20]}$ Victor Stenger and Leon Lederman are critical of attempts to use quantum mysticism to bridge any unexplained or seemingly implausible effects, believing these to be traits of modern pseudoscience.

To sum that up, the "law of attraction" hardly has a physical basis, and it hardly could as it's been defined, given the joint lack of measurability, testability, and falsifiability. If it has a psychological basis that might explain why you've observed multiple independent authors advocating vaguely the same idea, that basis is confirmation bias or selection bias, and the "law" is an illusory result of these biases. That is, it is not at all a law in the usual, scientific sense of a time-tested theory that explains a copious range of empirically verifiable facts; it is almost the furthest thing from a law in this sense. Advocates of the idea often borrow language from popularly recognized but poorly understood (by non-physicists) physical concepts like quantum mechanics and electromagnetism, but repurpose them to communicate metaphysical claims without clarifying whether their use is intended (a) as analogy, or (b) as literal claims for the physical mechanisms by which the metaphysical claims are proposed to operate.
I believe Alousi's criticism in the above quote was a response to the latter interpretation: I think he's arguing that thoughts are unlikely to directly cause physical effects outside the brain, presumably excluding effects on the rest of one's own body, and excluding effects that are mediated by behavior. No known process exists to affect "luck" or the realization of desires through thought alone, so it's unlikely we've overlooked some secret mechanism through which such an effect could operate. Conversely, it seems plenty likely that, for instance, thinking I deserve a cookie would result in me getting a cookie, if I don't exclude all the ordinary processes that mediate this effect (e.g., getting up, opening the cookie jar, stuffing my face)...but this is no secret.
(Full disclosure: I haven't read The Secret...and given my familiarity with its detractors, I'm not likely to.)
[Edit]: For another, broader response to the related concept of "autosuggestion," check out this question on skeptics.SE. @Articuno's answer cites some interesting studies that seem to have identified counterproductive effects of focusing on outcome goals (instead of process goals; Pham & Taylor, 1999) and positive fantasies of success before it is actually attained (Oettingen, 1996)! Maybe this is the real, dirty secret about The Secret that's most worth knowing.
References
Oettingen, G. (1996). Positive fantasy and motivation. In P. M. Gollwitzer & J. A. Bargh (Eds.), The psychology of action: Linking cognition and motivation to behavior, pp. 236–259. New York: Guilford Press.
Pham, L. B., & Taylor, S. E. (1999). From thought to action: Effects of process-versus outcome-based mental simulations on performance. Personality and Social Psychology Bulletin, 25(2), 250–260.


Why is the order of white/grey matter different in the brain and spinal cord?

I'll tackle this question from a functional point of view.

Gray matter are cell bodies, white matter are myelinated fiber tracts.

In the brain, the gray matter is basically the cortex, the white matter lies mainly underneath it. The Cortex is the place where all the higher mental processing takes place (Fig. 1).

Fig. 1. Cortical functions. Source: Penn Medicine

The white matter in the brain connects the various parts of the cortex so that information can be transported for further processing and integrated.

Fig. 2. Central white matter. Source: NIH Medline

Since the cortex is the 'processor', it makes sense to connect the parts subcortically (more efficient as it leads to shorter connections). However, the cortex has been expanding very late in evolution, so this 'endpoint reasoning' can be contested, because from an evolutionary perspective, more cortex was needed and hence it was expanded right where it happened to be, namely in the outer part of the brain.

In the spinal chord things are pretty much reversed; grey matter within, white matter around it (Fig. 3).

Fig. 3. Section through spinal chord with central grey matter and surrounding white matter. Source: University of Michigan

The white matter, again, is formed by various tracts (Fig. 4) and the grey matter with parts that are processing information (fig. 5).

Fig. 4. Section through spinal chord showing the spinal tracts forming the white matter. Source: Biology.SE

 Fig. 5. Section through spinal chord showing the spinal reflex arches forming the gray matter. Source: APSU Biology

The white matter in the spinal chord constitutes the various sensory and motor pathways to and from the brain, respectively. The gray matter constitutes basic processing nuclei that form the reflex arches in the spinal chord. These reflex arches process incoming sensory information (e.g. pain) and govern motor output (e.g., pulling the hand away from the fire).

Again, the structure makes sense in terms of efficiency, as the reflex arches combine the sensory and motor tracts to govern reflexes, and therefore processing them from within saves space.


How can I find literature about the connection between proprioception and thinking?

Two major terms:

"Spatial Representation":

of pitch height (lower/higher):

https://www.sciencedirect.com/science/article/pii/S0010027705000260

emotions (down/up):

https://www.tandfonline.com/doi/abs/10.1080/02699930500347794

"Spatial Analogy":
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5256459/

Some papers argue that even time has strong spatial representation in it:
https://www.sciencedirect.com/science/article/pii/S001002770700087X


Within the limbic system the hippocampus and  amygdala processes  memory.

hippocampus
The hippocampus processes declarative memory, the memory  recalled in the form of thought and stores memory.

  Hippocampal integrity plays a crucial role in intact memory functioning. Research has demonstrated that normal hippocampal development continues into early adulthood . Investigators specifically examining the development of the hippocampus have suggested that the hippocampal formation undergoes a steep increase in volume until approximately the second year of life, then the volume slowly increases throughout adolescence. 1

amygdala
The amygdala processes emotional memory by directing the stimulus to emotional.

  here is extensive evidence that the amygdala is involved in affectively influenced memory. The central hypothesis guiding the research reviewed in this paper is that emotional arousal activates the amygdala and that such activation results in the modulation of memory storage occurring in other brain regions.
  2

development of amygdala and hippocampus
The hippocampus and amygdala   are not fully developed until the ages of 9-11 years of age. there is evidence in studies that this development continues into early adulthood

  significant age-related changes in the volumes of amygdala and hippocampus. The developmental trajectories of the brain regions were best characterized by the cubic model, which demonstrated robust changes in the beginning of life, with the amygdalar and hippocampal volumes peaking around 9 to 11 years of age,..
  The results of the present study indicated that the maximum volume of the amygdala was reached between 9 and 11 years of age. 3

The amygdala is able to effective process emotional memory, independently of attention.

  The question addressed in this paper is whether the human amygdala processes threat-related stimuli independent of selective attention. This is considered from a functional neuroimaging perspective, describing studies in normal volunteers and patients with brain lesions. The conclusion is that the evidence for such automaticity is strong, indicating that important distinctions exist between emotion and other forms of cognition  4

The hippocampus, requires attention to process and recall memory.

  The hippocampus is critically involved in storing explicit memory such as memory for space. A defining feature of explicit memory storage is that it requires attention both for encoding and retrieval.  5

In conclusion:
As the parts of the brain that process memory are forming during the early years of life, given that emotional memory is more readily processed than declarative memory. It is possible to have experiences within the emotional memory, that have not got clear cut conscious memories.
This post about involuntary memory, discusses memory retrieval in a little more detail.

1. Abnormal Hippocampal Development in Children with Medulloblastoma Treated with Risk-Adapted Irradiation
Bonnie J. Nagela,g, Shawna L. Palmera, Wilburn E. Reddickb,f, John O. Glassb, Kathleen J. Heltonb, Shengjie Wuc, Xiaoping Xiongc, Larry E. Kunb, Amar Gajjard,e and Raymond K. Mulherna
2. Involvement of the amygdala in memory storage: Interaction with other brain systems
James L. McGaugh, Larry Cahill, and Benno Roozendaal
3. Uematsu A, Matsui M, Tanaka C, Takahashi T, Noguchi K, et al. (2012) Developmental Trajectories of Amygdala and Hippocampus from Infancy to Early Adulthood in Healthy Individuals. PLoS ONE 7(10): e46970. doi:10.1371/journal.pone.0046970
Ann N Y Acad Sci. 2003 Apr;985:348-55.
4. Amygdala automaticity in emotional processing.
Dolan RJ, Vuilleumier P.
Source
Wellcome Department of Imaging Neuroscience, Institute of Neurology, London WC1N 3BG, UK. r.dolan@fil.ion.ucl.ac.uk
5. What is remembered? Role of attention on the encoding and retrieval of hippocampal representations
Isabel A. Muzzio, Clifford Kentros and Eric Kandel


There are a range of "adjective checklists" that have been developed to assess affective states, personality traits, or characteristics of individuals. Two of the most widely cited measures are the Multiple Affective Adjective Check List (MAACL) and the Multiple Affective Adjective Checklist-Revised (MAACL-R) (Zuckerman & Lubin, 1965; Zuckerman & Lubin, 1985). Although the actual MAACL-R manual may require purchase, lists of the affective items are available in other publications (Gotlib & Meyer, 1986).

Clinically, I have used the How Do I Feel Right Now? chart for clients who have difficulty identifying and naming their emotional states (http://blogs.oregonstate.edu/careerservices/2012/11/30/emotional-intelligence-what-is-it-and-why-do-employers-want-emotionally-intelligent-employees/).

Other sources of emotion lists in the field of psychology include:

Shaver and colleagues have a heavily cited paper on types of emotions (1987)
The Geneva Emotional Music Scale (Zenter, Grandjean, & Scherer, 2008)

Gotlib, I. H., & Meyer, J. P. (1986). Factor analysis of the Multiple Affect Adjective Check List: A separation of positive and negative affect. Journal Of Personality And Social Psychology, 50(6), 1161-1165. doi:10.1037/0022-3514.50.6.1161

Shaver, P., Schwartz, J., Kirson, D., & O'connor, C. (1987). Emotion knowledge: further exploration of a prototype approach. Journal of Personality and Social Psychology, 52(6), 1061.

Zentner, M., Grandjean, D., & Scherer, K. R. (2008). Emotions evoked by the sound of music: Characterization, classification, and measurement. Emotion, 8(4), 494-521. doi:10.1037/1528-3542.8.4.494

Zuckerman, M., & Lubin, B. (1985). Manual for the MAACL-R: The Multiple Affect Adjetive Check List Revised. Educational and Industrial Testing Service.

Zuckerman, M., & Lubin, B. (1965). The Multiple Affect Adjective Checklist (MAACL).


Can the mind be trained to equanimously observe compulsive urges/cravings (without giving in / acting out)?

According to the article "Brief meditation training induces smoking reduction" one kind of mediation-training reduced smoking by 60% while a control group (relaxation training) showed no such effect.

"Integrative body-mind training (IBMT) is a form of mindfulness meditation that involves body relaxation, mental imagery, and mindfulness training accompanied by selected music background. Cooperation between the body and the mind is emphasized in facilitating and achieving a meditative state. The trainees concentrated on achieving a balanced state of body and mind guided by an IBMT coach and a compact disc. The method stresses no effort to control thoughts but, instead, a state of restful alertness that allows a high degree of awareness of body, mind, and environment."

Other relevant references:
Tang YY, et al. (2007) Short-term meditation training improves attention and self-regulation. Proc Natl Acad Sci USA 104(43):17152–17156.

Tang YY, et al. (2009) Central and autonomic nervous system interaction is altered by short-term meditation. Proc Natl Acad Sci USA 106(22):8865–8870.

Tang YY, et al. (2010) Short-term meditation induces white matter changes in the anterior cingulate. Proc Natl Acad Sci USA 107(35):15649–15652.

Tang YY, Lu Q, Fan M, Yang Y, Posner MI (2012) Mechanisms of white matter changes induced by meditation. Proc Natl Acad Sci USA 109(26):10570–10574.

Tang YY (2009) Exploring the Brain, Optimizing the Life (Science Press, Beijing).


Do cultures differ in the perception of emotions from body expression?

The following article PERCEPTION OF EMOTIONS
FROM FACES AND BODIES
AND THE INFLUENCE OF CONTEXT by Charlotte Sinke (I have quoted the aims and outline from) examines in depth interpretation of dynamic body language and cross cultural differences. It discusses the availability of studies with static images, facial expressions and voice and the relationship between these in perception and cross cultural differences. Although this doesn't examine a large range of cultures, it's interesting and provides a good resource of cited articles.

Research aims and thesis outline
Previous emotion research has mainly focused on the perception of facial expressions.
Only in recent years, bodily expressions are being studied. This has been done by
using pictures of isolated bodies. However, in our daily life, bodies are not static
and do not appear in isolation. Therefore, the stimuli used in Chapter 5 and 6 are
dynamic. There is reason to believe that the perception of faces and bodies might be
influenced by the context it is in. This can be the physical environment, the culture, or
other people. The question therefore is how a face or a body, being emotional or not,
is processed differently in specific contexts. Since everything that we do involves
in some way other people, it is interesting to find out how the brain responds to an
interaction between two people and whether it notices subtle differences in body
language that can indicate whether a threat is going on. A final question was how
attention can play a role in this perception.
Across cultures the expression of basic emotions is remarkably similar. However,
emotion perception can be influenced by other factors, like the (social) context.
Whether people from different cultures are differently influenced by this will be
discussed in Chapter 2. More specifically, Dutch and Chinese students were tested on
whether they show differences in the recognition of facial but also bodily expressions
and whether they are differently influenced by context. The studies described in this
chapter are purely behavioural.
Moving away from cultural differences, in Chapter 3 the influence of context on
face processing is investigated using fMRI. Chapter 4 elaborates on the data from
this study. Here, the activation of extrastriate body area is discussed in relation to its
response to threatening scenes specifically.
The study performed in Chapter 5 moves from static pictures to dynamic movies
of two people interacting. This interaction was either threatening or teasing. A
difference is made in whether participants actively try to guess what goes on in each
situation or perform an unrelated task. Chapter 6 expands on perceiving threatening
social interactions by using two different attention levels and letting the participant
focus on only one of the two protagonists (always one of them being angry at the
other) in each movie.
Finally, in Chapter 7, the insights gathered from the preceding chapters are
summarized.

Charlotte Sinke
PDF
Interesting quote:

“Every phase of movement, every small transference of weight, every single gesture
of any part of the body reveals some feature of … inner life.”
~ Rudolf Laban ~


I personally have had the experience that you can train your ability to hold a mental image of what you see.

I have been drawing from life as a hobby off and on for more than twenty years, and one of the exercises that help you with learning to draw in a realistic manner is to look at your subject for several seconds and then turn to your canvas and draw what you have seen without looking back at it. With time you become better at this until you can hold a rather detailed representation of what you saw in your mind. This image is limited to what you focussed on, obviously, so parts of the background or anything you found uninteresting will be blurred or missing, and the detail is not very fine, so I can't count matches. And it most certainly does not work for random dots.

But I draw only as a hobby, spend little time on it even at my most intense phases and have long stretches of time where I don't draw at all. I believe I could get very much better at this, and don't need autims to accomplish it.

Minsky (or you) will probably counter that I'm "using mnemonics and other, non-eidetic memory enhancing exercises", but looking at your example of "quickly memoriz[ing] ... a page of text in a few seconds", I see a problem that would make eidetic memory – in the sense of storing the raw data of what you see without processing it – pretty much impossible anyway:

Only the central 2° of your field of vision are focussed and sharp. If you look at a page of text without letting your eyes roam over it, you will have a thumbnail-sized area of sharp and readable text, and a whole page of blurred text. If you want to know how blurred, focus on the dot at the end of this sentence and try to read the lines below it. So obviously, if you want to store a whole page (or any detailed image), you'll have to let your eyes "scan" it. But what do you do, when you do that? You send a row of images to your brain, and your brain has to process them to build the whole page from that. That's processing, if you want to put a name to it. So, to say this clearly: It is impossible to view a whole page without processing it.

What this means is that everybody who looks at anything through their eyes has to process the information. And what happens during this processing? No-one knows, not even Marvin Minsky. Maybe it remains raw and unchanged apart from the assembly. But maybe – or rather, very likely – there's a whole lot of top-down processing going on, making sense of what is seen, relating it to other stored information, preparing it for easy storage. Perhaps there are individuals whose brains are exceptionally quick at this, and who have a larger than average storage capacity in their working memories. From the outside this would look a lot like eidetic memory.


What tasks does Bayesian decision-making model poorly?

There is currently a lot of debate surrounding what questions Bayesian modeling is appropriate for answering within cognitive science, as well what makes a "poor model."  Unfortunately these become extremely thorny issues very quickly, partly because what is called "bayesian modeling" actually refers to a rather heterogeneous set of approaches and philosophies, and partly because different models serve very different purposes, making the definition of a "poor model" very difficult to agree on.

Nonetheless, I can strongly recommend two papers that deal with these issues in depth.  The first is Jones & Love's 2011 Behavioral & Brain Sciences paper "Bayesian Fundamentalism or Enlightenment? On the explanatory status and theoretical contributions of Bayesian models of cognition."  Fortunately, BBS articles include open peer commentary - so you can see the reaction of the larger field to their claims.

The second paper is Bowers & Davis's 2012 Psychonomic Bulletin & Review article titled "Bayesian just-so stories in psychology and neuroscience." These papers both make very credible arguments that Bayesian models are actually "poor models" even when they would claim to be good; both papers highlight a number of phenomena that are difficult to fit with Bayesian models without resorting to the same kinds of parameter twiddling that Bayesians tend to criticize other modelers for.

Finally, there is a paper that just came out today describing the failure of a Bayesian model to capture some phenomena in the domain of causal reasoning.  This has been traditionally understood as a relative strong suit of Bayesian modeling, making the findings of this paper somewhat striking.  I have not read it, but it's in press by Bes, Sloman, Lucas & Raufaste at Cognitive Science, titled "Non-Bayesian Inference: Causal Structure Trumps Correlation."

References

Bowers, J.S. & Davis, C.J. (2012). Bayesian just-so stories in psychology and neuroscience.. Psychological bulletin, 138, 389.PDF
Jones, M. & Love, B.C. (2011). Bayesian Fundamentalism or Enlightenment? On the explanatory status and theoretical contributions of Bayesian models of cognition. Behavioral and Brain Sciences, 34, 169-188. PDF
Bes, B., Sloman, S., Lucas, C.G. & Raufaste, E. (2012). Non-Bayesian inference: Causal structure trumps correlation. Cognitive Science. PDF


Comorbidity of Neurodevelopmental Disorders between them and Obsessive Compulsive Disorder and Obsessive Compulsive Personality Disorder

I found your question hard to answer because of the multiple disorders involved. I hope my answers contains some information that is usefull to you. However, it is likely not the satifsying answers you are looking for.

According to Hansen, Oerbeck, Skirbekk, Petrovski, & Kristensen (2018) about 21 percent of children with neurodevelopmental disorders (ND) have one comorbid disorder in the category of neurodevelopmental disorders. For ADHD and Autism Spectrum Disorder (ADS), tic disorder was the most common ND. 36% of ADHD patients had tic disorder as well and 44% ASD patients had a tic disorder. As for OCD, 3.3% of the patients with ADHD also had OCD and 4.0% of the patients with ASD had OCD as well. This study did not investigate the OCPD as a possible comorbid disorder for neurodevelopmental disorders. After doing some more searching, I unfortunately could not find much information about OCPD in relation to Neurodevelopmental disorders and the specific example your provided (OCD, OCDP, ADHD and ADS). However, that does not mean it is not possible, in practice all kinds of comorbidities can occur. The behavior of these patients would likely reflect the symptoms of all the disorders present in the patient.

A big problem with our current understanding/diagnosis of disorders is that most of the disorders are categorized based on their symptoms (e.g. DSM V). In practice symptoms between disorders heavily overlap resulting in comorbidity for most patients (Nolen-Hoeksema, 2014). It is often mandatory to diagnose multiple disorders. For example, if the patient meets both the criteria for ADHD and Autism Spectrum Disorder, then both disorders need to be diagnosed, same goes for OCD and OCPD (see DSM V, Chapters about Neurodevelopmental Disorders and Personality Disorders). Sometimes patients are believed to have "hybrid disorders" (multiple symptoms of multiple disorders). Therefore, it would be better to classify disorders according to their causes instead of the symptoms. That would be the first step in truly explaining disorders instead of simply describing them (Davey, 2014).

References

American Psychiatric Association. (2013). Diagnostic and statistical manual of mental disorders (5th ed.). Washington, DC: Author.

Davey G. (2014). Psychopathology: Research, Assessment & Treatment in Clinical Psychology (2nd ed). British Psychological Association and John Wiley & Sons LTD.

Hansen, B., Oerbeck, B., Skirbekk, B., Petrovski, B., & Kristensen, H. (2018). Neurodevelopmental disorders: Prevalence and comorbidity in children referred to mental health services. Nordic Journal of Psychiatry, 72(4), 285-291. doi:10.1080/08039488.2018.1444087

Nolen-Hoeksema, S. (2014). (Ab)normal psychology (6th ed.). New York: McGraw-Hill Education


Are there any EEG procedures currently available/in development that can formulate letters/words from deliberate, internal monologue?

What you are looking for is Imagined / Silent Speech Classification (my best guess). I'm interested in this for a few years (exactly to work with Vim) now and  worked with some of the cheap EEG headsets like Emotiv EPOC and Neurosky MindWave Mobile.

A paper on it:
http://www.scipublish.com/journals/ABSE/papers/1021

Patent applications:
http://www.freepatentsonline.com/
To the above link, add these at the end:
WO2014066855A1.html
WO2014130571A1.html

(Due to a lack of reputation, I cannot post more than 2 links.)

The commercial and inexpensive headsets are good enough to detect what their APIs support:
Neurosky: Attention, Meditation and Eye blink.
EPOC: Please refer to their Cognitive Suit documentation. You can get 1-2 sets of detections done quickly. Good luck with detecting 4 states.

Search around for Silent Speech Classification. You should be able to find more details. There was a Japanese demo somewhere that uses classification on EEG or EMG to speak. I will post it if I can find it.


Visual masking has quite a few variations, and the source you've linked is by far the worst explanation I've seen.

In forward masking an early stimuli takes hold over consciousness (resulting in top-down activation) that prevents a later stimuli from overshooting the selective attention threshold, thus the latter remains subliminal (limen is threshold in Latin, so sub-liminal is literally below threshold).

For example, in the following frame sequence you'd be asked to find the letters in a sequence of numbers. Given there's less than 100ms between the two targets, your conscious attention to the first target will almost always prevent the second target from being perceived.

For a nice demo of this have a look at this attentional blink test video.

Another variation is to expose a frame for less than 30ms between various pre or post masks.

The principle, however, is always the same - paying attention to one stimuli 'saturates' our consciousness and prevents another from entering it.


Why do psychologists often not use mathematical models to express their theories?

Come read some cognition! It's a wide open field with angles on all kinds of psychology stuff, and we're having a great time throwing greek letters around like confetti. I think you might like it!
One of my favorite recent pro-model rants is this one psyarxiv.com/rybh9/ Although, to be fair they do argue for 'computational' rather than 'mathematical'. I would argue these both mean 'explicit formalism', which is what you're after here?
There's a whole journal of mathematical psychology
www.journals.elsevier.com/journal-of-mathematical-psychology
or Computational Brain and Behavior www.springer.com/journal/42113
is full of cool stuff on a surprisingly wide range of psych topics united by a common theme of awesome mathy-ness
Psych is very broad, but whatever corner of it you're interested in, there's almost certainly a math-y cognitive/computational version of it (as well). Those mathpsych folks definitely get around. Probably the most math-resistant corner of psych is social psych, emergent behavior of groups type stuff is absolutely vicious to model, as you would know, coming from econ... but see eg. cogsci.mindmodeling.org/2019/papers/0172/0172.pdf
Explicit formalism is the future of psych, and quite a lot of the future is here already


Has the neuro-linguistic programming visual model been scientifically tested?

Yes, there's been scientific tests. No, they did not support the propositions. However, some supporters of the propositions argue that existing empirical tests have methodological problems.

There's a discussion of scientific evaluation for NLP on wikipedia that cites several review articles.

Quoting the Heap (1988) review as quoted in Wikipedia:

  Michael Heap (1988) conducted a systematic review of the research
  literature on NLP and found that it was lacking in evidence.

  The present author is satisfied that the assertions of NLP writers
  concerning the representational systems have been objectively and
  fairly investigated and found to be lacking. These assertions are
  stated in unequivocal terms by the originators of NLP and it is clear
  from their writings that phenomena such as representational systems,
  predicate preferences and eye-movement patterns are claimed to be
  potent psychological processes, easily and convincingly demonstrable
  on training courses by tutors and trainees following simple
  instructions, and, indeed, in interactions in everyday life. Adding,

  Therefore, in view of the absence of any objective evidence provided
  by the original proponents of the PRS hypothesis, and the failure of
  subsequent empirical investigations to adequately support it, it may
  well be appropriate now to conclude that there is not, and never has
  been, any substance to the conjecture that people represent their
  world internally in a preferred mode which may be inferred from their
  choice of predicates and from their eye movements. […] These
  conclusions, and the failure of investigators to convincingly
  demonstrate the alleged benefits of predicate matching, seriously
  question the role of such a procedure in counselling.

References:

Heap, M. (1988). Neuro-linguistic programming, In M. Heap (Ed.) Hypnosis: Current Clinical, Experimental and Forensic Practices. London: Croom Helm. FREE PDF


I have found the following — all mention van Norden, (1975):

Chang, A.-C., Lutfi, R., Lee, J., & Heo, I. (2016). A Detection-Theoretic Analysis of Auditory Streaming and Its Relation to Auditory Masking. Trends in Hearing, 20DOI: 10.1177/2331216516664343 PMCID: PMC5029798

  Abstract

  Research on hearing has long been challenged with understanding our exceptional ability to hear out individual sounds in a mixture (the so-called cocktail party problem). Two general approaches to the problem have been taken using sequences of tones as stimuli. The first has focused on our tendency to hear sequences, sufficiently separated in frequency, split into separate cohesive streams (auditory streaming). The second has focused on our ability to detect a change in one sequence, ignoring all others (auditory masking). The two phenomena are clearly related, but that relation has never been evaluated analytically. This article offers a detection-theoretic analysis of the relation between multitone streaming and masking that underscores the expected similarities and differences between these phenomena and the predicted outcome of experiments in each case. The key to establishing this relation is the function linking performance to the information divergence of the tone sequences, DKL (a measure of the statistical separation of their parameters). A strong prediction is that streaming and masking of tones will be a common function of DKL provided that the statistical properties of sequences are symmetric. Results of experiments are reported supporting this prediction.

Krogholt Christiansen, S., & Oxenham, A. J. (2014). Assessing the effects of temporal coherence on auditory stream formation through comodulation masking release. The Journal of the Acoustical Society of America, 135(6): pp. 3520—3529.DOI: 10.1121/1.4872300 PMCID: PMC4048442

  Abstract

  Recent studies of auditory streaming have suggested that repeated synchronous onsets and offsets over time, referred to as “temporal coherence,” provide a strong grouping cue between acoustic components, even when they are spectrally remote. This study uses a measure of auditory stream formation, based on comodulation masking release (CMR), to assess the conditions under which a loss of temporal coherence across frequency can lead to auditory stream segregation. The measure relies on the assumption that the CMR, produced by flanking bands remote from the masker and target frequency, only occurs if the masking and flanking bands form part of the same perceptual stream. The masking and flanking bands consisted of sequences of narrowband noise bursts, and the temporal coherence between the masking and flanking bursts was manipulated in two ways: (a) By introducing a fixed temporal offset between the flanking and masking bands that varied from zero to 60 ms and (b) by presenting the flanking and masking bursts at different temporal rates, so that the asynchronies varied from burst to burst. The results showed reduced CMR in all conditions where the flanking and masking bands were temporally incoherent, in line with expectations of the temporal coherence hypothesis.

Winkler, I. & Schröger, E. (2015) Auditory perceptual objects as generative models: Setting the stage for communication by sound. Brain and Language 148(1): pp. 1—22DOI: 10.1016/j.bandl.2015.05.003 PMID: 26184883

  Abstract

  Communication by sounds requires that the communication channels (i.e. speech/speakers and other sound sources) had been established. This allows to separate concurrently active sound sources, to track their identity, to assess the type of message arriving from them, and to decide whether and when to react (e.g., reply to the message). We propose that these functions rely on a common generative model of the auditory environment. This model predicts upcoming sounds on the basis of representations describing temporal/sequential regularities. Predictions help to identify the continuation of the previously discovered sound sources to detect the emergence of new sources as well as changes in the behavior of the known ones. It produces auditory event representations which provide a full sensory description of the sounds, including their relation to the auditory context and the current goals of the organism. Event representations can be consciously perceived and serve as objects in various cognitive operations.


Alternatives to "Honest Signals" theory of non-semantic communication

A related theory of latent dimensions of emotional expression is Affect Control Theory (ACT), which can be broken into four separate dimensions in "The World of Emotions Is Not Two-Dimensional" by Fontaine et al. Three of these dimensions map easily onto Honest Signals. This is shown in the table below:

The mismatching dimensions of ACT and Honest Signals are Valence/Pleasantness and Mimicry. This makes sense since ACT is more focused on the expression and perception of emotions, whereas Honest Signals is more about the co-operation of two individuals. In other words, when two people are interacting, it's more important if one person is responding to that other person's emotions than what that emotion is. This is interestingly confirmed in Non-Violent Communication, which establishes that mirroring an emotion must be done before the root cause of that emotion can be addressed.


Ambiguity in self-evaluating Likert-scale questions

I believe that in the first part there is some confusion of empathy and self-concept ("Does Not Describe Me Well" to "Describes Very Well"), although the basic statement refers to empathy that question is made to measure self-concept of empathy. The vast majority of tests (which do not measure performance) measure self-concept dimensions. Of course you can not measure empathy by a test, what you measure are dimensions of self-concept in relation to empathy. Empathy could be measured through behavioral registers (see attachment studies).

With regard to the second part:

Ideally the test should not be ambiguous in any item (although it is common for people to comment in this regard).
Given the impossibility in most of the tests to request frequencies of behavior are usually asked similar questions.
It must be taken into account that these questions are made in test format likert, it would be a serious mistake to ask similar questions in dichotomous format.
If there is ambiguity in the test this has to be reflected psychometrically as a low correlation and error variance, provided that questions are asked that correlate with the reference question, that is to say, that usually several questions of this type are made and their Relationships when designing the test (you can also study it on your own for a class work).
The administration of the test must be performed under conditions that allow questions to be asked and the professional (or student who must know the test in detail) should clarify any doubts to the person to whom the test is administered, therefore in some countries, someone who has not studied psychology can not administer or correct (legally or validly) a psychological test.

Personally, when I require empathy measurements I always use the TECA (acronym in Spanish)
https://web.teaediciones.com/TECA--TEST-DE-EMPATIA-COGNITIVA-Y-AFECTIVA.aspx
It allows to measure cognitive and affective components (essential in the present moment): adoption of perspectives, emotional compression, empathic stress and empathic joy. Try to translate.


How many possible states does a brain have?

2 2,752,000,000,000,000,000,000 states

  Disclaimer: This is obviously a very crude and imprecise estimation (in fact, it is ignoring some obvious parameters for the sake of simplicity). As Scott E. Page puts it: Even models that are far from accurate can teach us something.

If one considers the design of future artificial brain, you can make these rough assumptions:

A 32 bit floating point representation should suffice to capture synapse elasticity.
There are about 86 billion neurons in the brain. The connectivity of which can be represented by a square matrix of size 86 * 1018 (86 * 109 to the power of 2). Each connection is weighted, 32-bit float.

Resulting in 86 * 1018 * 32 bits =

2752000000000000000000 bits (2.75 sextillion).

These many bits result in these many states:

2 2752000000000000000000

or:

This obviously a very rough estimation - you don't account, for example, to membrane potential, although you can argue that discarding membrane potential while maintaining neural connectivity and synaptic strength should suffice to 'reignite' a frozen brain.

Perhaps more importantly, a network structure can be represented by a matrix, but more often is represented by a sparse matrix - no neuron is connected to all other neurons, I believe 1000 is the average and some sources state that there are about 1,000 trillion synaptic connections.


What is the term for a psychological effect which does not have a neurobiological/genetic basis?

As I alluded in the comments, I think your question is underpinned by a more fundamental worry of the "best level of description" for psychological phenomena. If you a reductionist then you believe that all of psychology is best explained in terms of the activity of neurons (or systems of neurons if you are of the system perspective; note that some do not consider this reductionist. However, it does reduce to the physical basis).

On the other hand, Putnam and Fodor (and I suspect most proponents of strong AI) argue for multiple realizability: mental states and psychology can be implemented in various physical substrates, not just biological neurons. If you subscribe to this view, then it is natural to expect the best level of description of psychology to be independent of the specifics of a physical implementation (think algorithm-analysis in theoretical computer science). Since brains are physical things that implement minds, you would believe that a neurobiological basis does exist, but its details are irrelevant to your theory. Note that many theories in psychology can be viewed at the macro- or behaviorist level and as I suggested earlier: many theories in cognitive science lack a solid neuronal grounding.

If you have a physics background, then the weak analogy I would make is thermodynamics versus statistical mechanics. Thermodynamics is a macro-level theory that can exist without micro-level detail. However, eventually thermodynamics found a micro-level grounding in statistical mechanics. Does that mean we abandon thermodynamics and only study stat mech?

As for your nature vs. nurture distinction, if we accept mutliple realizability then we can use the above ideas to try to formalize the terminology. We can think of nature features as ones that are best described at the level of the specific implementation of the human brain, and nurture features as ones that are best described on a macro-level that would apply to any reasonable implementation. I don't know if this idea has been deeply studied or if it has any interesting bearing on the nature vs. nurture debate.


Is the belief that a consultant knows more than the team a form of cognitive bias?

Yes, this could be a cognitive bias. Quite clearly, a consultant is expected to be more knowledgeable about the specific topic they were hired to consult on.

  A consultant (from Latin: consultare "to deliberate") is a
  professional who provides expert advice.

Consultants are supposed to be experts in their field, and as a result they carry some authority. Therefore, authority bias comes to mind:

  Authority bias is the tendency to attribute greater accuracy to the
  opinion of an authority figure (unrelated to its content) and be more
  influenced by that opinion.

The bolded addendum in between parentheses is important. As long as based on the content the consultant brings to the table you respect their opinion, there is no cognitive bias (no irrationality); they are simply doing a good job.

But, not all 'consultants' are experts per se. In software development specifically, I have the impression 'consultancy' has almost become synonymous with 'temporary hire'. Newly grads often get hired straight out of school in consultancy firms. In such cases, there might be a cognitive bias at play, when it is not the contributed content which is evaluated (as you outline in your answer), but merely the title the consultant carries.


The following, and more, is available at my blog article Microbiome and Probiotics: Gut bacteria can affect your mental health?
Answer to Question 1:

Can poor mental health affect the bidirectional communication between gut microbes and the brain?

Even though there is cross talk between your enteric nervous system (ENS) and your brain, researchers assumed that microbes did not play into it. But recent breakthroughs are challenging that assumption, and changing our understanding of how the blood brain barrier works, because the microbiome can affect your brain in some pretty big ways.
The ENS is a massive web spread over your entire digestive tract made up of more than 500 million neurons that control your guts. This second brain as it is sometimes called, is pretty much self sufficient, and can take care of most of its jobs by itself. But it is connected to the CNS through your vagus nerve, which is an information superhighway between your gut and your brain.
Stress affects your microbiome
Early research starting in the 1970s (Tannock & Savage, 1974) showed that stress could affect the kind of microbes found in the guts of mice. One group found that stressing mice by depriving them of food or water, caused them to have more coliform bacteria like E.coli, and less of another form of bacteria called lactobacilli in their intestines.
Another group found that the stress of dealing with an aggressive cage mate led to changes in amounts of other kinds of bacteria. They found increased numbers of Bacteriodes and Clostridium, along with decreased numbers of Coprococcus, Pseudobutyrivibrio and Dorea.
But even though it was clear that stress could affect the kinds of microbes in the intestines, it wasn’t clear if that was a 2 way relationship.
Could Gut microbes be affecting psychological stress levels?
The first big break on this question came when some scientists from Kyushu University, Japan (Sudo, et al. 2004), discovered that exposure to certain kinds of microbes had dramatic effects on brain chemical levels.
For this study, the scientists used germ free mice. These were mice delivered by C section and immediately put into super clean cages, so they were barely exposed to microbes at all. They also made comparisons with specific pathogen free mice. These were mice only exposed to a known set of microbes.
The germ free mice got a lot more stressed when they were restrained, so it was something about the bacteria in the specific pathogen free mice that was helping them with their stress levels.
The team found that the germ free mice had less of a protein called Brain-derived neurotrophic factor (BDNF). BDNF is important for learning, memory, and higher order thinking. The germ free mice had less of it in the brain regions that determine how an animal reacts to stress.
Answer to Question 2 and 3:

Can consuming products containing probiotics be used to help with mental health problems? If so, can consuming products containing probiotics when well cause mental health problems?

There is not a lot of research that is very clear on the relationship between the gut and the brain in humans. These discoveries are so new that nobody has been able to do any large scale studies in humans yet. But along with prebiotics (fibre suppliments designed to feed good bacteria), small studies have tried treating volunteers with probiotics, deliberately introducing new microbes in to there guts, and the microbes and fibre affected the subjects mood and cognition.
So there might be a relationship between your microbiome and your mental health. But the studies have not been able to look closely enough at what exactly the prebiotics and probiotics are doing to the microbes in the gut, or how that may be translating in to changes in mood.
What does this mean?
Researchers will be getting more into the nitty gritty of these relationships and trying to work out whether these discoveries can translate into medical treatments.
Other scientists are trying to work out how to humanize the mouse microbiome, making the mouse microbiome more human like. They are doing this by taking faecal matter from sick and healthy human patients and inserting them into mice to study the effects.
That kind of experiment can let researcher pick apart how differences in the microbiomes connects with changes in mental health. They can also get right into the brains of mice in ways they can’t with human patients, using dissected tissues to look directly at the structures of brain cells and how they connect.
Can we tailor our microbiome for maximum benefit?
Some researchers are also trying to figure out how specific kinds of microbes are affecting our brains and how we can tailor our microbiomes to maximize the health benefits.
Others are starting to ask questions about how other things that affect our microbiomes like antibiotics could be affecting our mental health and cognition.
So there is still a lot we don’t know about how our microbiome can affect our brain. But there are a lot of new studies in the works and scientists and doctors are hoping that as our knowledge of how our Brain-Gut-Microbiome Axis grows, so will our ability to tweak it and hopefully improve some lives along the way.
Further Reading
Bailey, M. T., Dowd, S. E., Galley, J. D., Hufnagle, A. R., Allen, R. G., & Lyte, M. (2011). Exposure to a social stressor alters the structure of the intestinal microbiota: implications for stressor-induced immunomodulation. Brain, behavior, and immunity, 25(3), 397–407. doi: 10.1016/j.bbi.2010.10.023 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3039072/pdf/nihms253984.pdf
Bercik, P., Denou, E., Collins, J., Jackson, W., Lu, J., Jury, J., … & Verdu, E. F. (2011). The intestinal microbiota affect central levels of brain-derived neurotropic factor and behavior in mice. Gastroenterology, 141(2), 599-609. doi: 10.1053/j.gastro.2011.04.052 Free PDF: https://www.gastrojournal.org/article/S0016-5085(11)00607-X/pdf
Carabotti, M., Scirocco, A., Maselli, M. A., & Severi, C. (2015). The gut-brain axis: interactions between enteric microbiota, central and enteric nervous systems. Annals of gastroenterology, 28(2), 203–209. pmcid: PMC4367209 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4367209/pdf/AnnGastroenterol-28-203.pdf
Furness J.B., Callaghan B.P., Rivera L.R., Cho HJ. (2014) The Enteric Nervous System and Gastrointestinal Innervation: Integrated Local and Central Control. In: Lyte M., Cryan J. (eds) Microbial Endocrinology: The Microbiota-Gut-Brain Axis in Health and Disease. Advances in Experimental Medicine and Biology, vol 817. New York, NY: Springer. doi: 10.1007/978-1-4939-0897-4_3
Human Microbiome Project Consortium (2012). Structure, function and diversity of the healthy human microbiome. Nature, 486(7402), 207–214. doi: 10.1038/nature11234 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3564958/pdf/nihms378076.pdf
Mayer, E. A., Knight, R., Mazmanian, S. K., Cryan, J. F., & Tillisch, K. (2014). Gut microbes and the brain: paradigm shift in neuroscience. The Journal of neuroscience : the official journal of the Society for Neuroscience, 34(46), 15490–15496. doi: 10.1523/JNEUROSCI.3299-14.2014 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4228144/pdf/zns15490.pdf
Mayer, E. A., Tillisch, K., & Gupta, A. (2015). Gut/brain axis and the microbiota. The Journal of clinical investigation, 125(3), 926–938. doi: 10.1172/JCI76304 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362231/pdf/JCI76304.pdf
Reardon, S. (2014). Gut–brain link grabs neuroscientists. Nature News, 515(7526), 175. doi: 10.1038/515175a Free PDF: https://www.nature.com/news/polopoly_fs/1.16316!/menu/main/topColumns/topLeftColumn/pdf/515175a.pdf
Smith, P. A. (2015). The tantalizing links between gut microbes and the brain. Nature News, 526(7573), 312. doi: 10.1038/526312a Free PDF: https://www.nature.com/news/polopoly_fs/1.18557!/menu/main/topColumns/topLeftColumn/pdf/526312a%20corrected.pdf
References
Sudo, N., Chida, Y., Aiba, Y., Sonoda, J., Oyama, N., Yu, X. N., … Koga, Y. (2004). Postnatal microbial colonization programs the hypothalamic-pituitary-adrenal system for stress response in mice. The Journal of physiology, 558(Pt 1), 263–275. doi: 10.1113/jphysiol.2004.063388 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1664925/pdf/tjp0558-0263.pdf
Tannock, G. W., & Savage, D. C. (1974). Influences of dietary and environmental stress on microbial populations in the murine gastrointestinal tract. Infection and immunity, 9(3), 591–598. pmcid: PMC414848 Free PDF: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC414848/pdf/iai00243-0111.pdf


Can I use data taken in a 5-point Likert Scale, and convert it as if it were taken as a 4-point Likert?

In general, from my extensive experience, using a four or a five point response scale is not going to change much the psychometric properties of a typical psychological self-report scale (e.g., reliability and factor loadings). I also imagine that if you were to measure a multi-item scale with a four point version and a five point version that the correlation would be very close to the test-retest correlation you get with the five point scale.

More extreme changes (e.g., using a 2-point instead of a 5-point) or radically altering the response options would eventually start to create issues, but in the 4 to 7 point range, I think the effects would be subtle, especially if you are dealing with a multi-item scale.

The main issue you will have is that you wont be able to compare your descriptive statistics (e.g., means and standard deviations) with other authors who have used the standard 5-point scale. Whether this is an issue, depends on the aims of your analyses. If you are focused on relationships between variables (e.g., correlations, regressions, group differences, SEM, and so on), then whether you use a 4 or a 5-point scale is not going to make much difference. If you want to compare the means of your sample to the means of previous samples, or if there are particular scoring rules that involve the original metrics (e.g., some tests have cut-off scores used for classification), then you have more of a problem.

There are ways to approximate a rescaling. I.e., estimating what the means and SDs would have been had you used the 5-point instead of the 4-point scale.

rescaled_old_score =  (old_score - OLD_MIN) / (OLD_MAX - OLD_MIN)
new_score = rescaled_old_score * (NEW_MAX - NEW_MIN) + NEW_MIN

Here's what the function looks like in R:

rescale_item <- function(old_score, old_min = 1, old_max = 4, new_min = 1, new_max = 5) {
    rescaled_old_score <-  (old_score - old_min) / (old_max - old_min)
    rescaled_old_score * (new_max - new_min) + new_min
}

template <- data.frame(original = 1:4)
template$new <- round(rescale_item(template$original, 1, 4, 1, 5), 2)
template

which leads to the following rescaling:

  original  new
1        1 1.00
2        2 2.33
3        3 3.67
4        4 5.00

Of course, this is only an approximation. Better estimates of the mapping values could be obtained by administering the tests using both scales to the same sample.