# Question
Title: What are the current suggested models for Primacy Effect in memory recall or personality impression?
What are the current suggested normative, mechanistic or phenomenological models for explaining **primacy effect** as was observed by Solomon Asch (1946) on personality impression, list-of-words memory recall and other forms as was reviewed extensively in one example of primacy in wine tasting by Mantonakis et al. (2009)?

* Mantonakis, A., Pauline Rodero, Isabelle Lesschaeve, and Reid Hastie (2009). Order in Choice: Effects of Serial Position on Preferences. Psychological Science November 2009 20: 1309-1312, doi:10.1111/j.1467-9280.2009.02453.x
* Asch, S.E. (1946). Forming impressions of psychology. Journal of Abnormal and Social Psychology, 41, 258. FREE PDF

# Answer
Primacy is one of several memory phenomenon often associated with serial recall--the other most common being the recency effect. There have been several computational models which attempt to establish an integrated account of serial recall (list memory). I will briefly cover to two such models, one ACT-R and one connectionist model.

# ACT-R

ACT-R is a hybrid (symbolic and sub-symbolic) cognitive architecture used to model a variety of tasks. It contains a detailed memory module, which is the oldest and most well-validated component in ACT-R (though this distinction does not necessarily apply to its explanation of primacy specifically).

Anderson et al. (1998) explain the primacy effect as an interaction of two mechanisms:

> The tendency for the **earlier items to receive greater rehearsal** is one factor that is producing the primacy. The other factor is the **lower positional confusions** among items at the beginning of the list.

The first mechanism, greater rehearsal, refers to the fact that items that are encountered sooner have more time to be rehearsed in working memory. Rehearsal is considered an important component of many influential working memory models, such as Baddeley's model of working memory. Rehearsal in the ACT-R model is accomplished through production rules. Sub-symbolically, rehearsing an item leads to an increase in the base-level activation of a chunk according to the base-level activation equation:

> $\beta=ln(\sum\_{j=1}^{n}t\_j^{-d})$

In this equation, a chunk's activation is determined by the *frequeny* ($n$) with which a chunk is encountered and the recency of each occurence ($t\_j$). Rehearsing an item increases $n$, and thus increases its activation level. Chunks are retrieved using the softmax activation function, and neural noise may lead to incorrect retrievals.

The authors justify the use of rehearsal mechanisms, arguing that

> In experiments where an effort is made to eliminate rehearsal the primacy effect goes away.

The second mechanism, positional confusion, relies on the fact that each item in the list is stored in a memory trace along with its neighbors. Thus, a memory "chunk" stores not only the item itself, but also the numbers that come before and after it in the list. The partial-matching mechanism in ACT-R leads to memory retrievals in which a neighbor is mistakenly retrieved in place of the item itself. The first and last items of the list have only one neighbor, while items in the middle of the list have two neighbors. Thus, there is an increased chance that numbers in the middle of the list will be transposed.

# Neural Networks

Botvinick & Plaut (2006) used a recurrent neural network to model list memory. Recurrent neural networks are a common way to model temporal order of events in neural networks. They are also an increasingly popular explanation of how working memory might be implemented in the brain.

Like the ACT-R model, Botvinick & Plaut note the tendency to transpose items during recall:

> Note that elements at both the beginning and the end of a list have fewer positional near neighbors than items toward the middle. This makes it relatively unlikely that the positions of elements near the list boundaries will be mistaken for other, similarly represented positions.

Their model also leverages a second mechanism to model the primacy effect, but it is not *explicit* rehearsal. Instead, it relies on the dynamics of recurrent neural networks to encode earlier items with greater reliability:

> Consider that when the first element in a list is encoded, there are no other elements yet represented in the hidden layer. When the second item is encoded, there is only one other element represented there. With each successive element encoded, the number of elements already in memory continues to increase. This provides a partial explanation for the primacy effect. As noted a moment ago, the more items held in memory at any given time, the more difficult the overall representation becomes to decode. This means that items at early list positions have an advantage, because during the overall period from encoding to recall they share the hidden layer with relatively few other elements.

It is also worth reading Botvinick & Plaut (2006) for their comparison of their own model to several others in the literature, including an earlier version of Anderson's. Briefly, they state:

> It is difficult to compare this ACT-R account with the model we have presented \[...\] because several critical aspects of the account (such as the functioning of the position pointer and the basis for similarity between position representations) are directly stipulated, without an explicit account of the underlying mechanisms or representational structure. \[...\] This being said, the Anderson and Matessa model, unlike the context-based models we have cited, can also be viewed as portraying item and position information as being stored together, as part of a single, structured representation. If viewed from this perspective, the theory has a bit more in common with the account we have put forward.

# Summary

In sum, the two models discussed share some similarities. Both models account for primacy partially through positional confusion during retrieval. The ACT-R relies on explicit rehearsal, whereas the neural network model does not. Though it ignores higher-level strategies, the neural network model can be seen as a lower-level explanation of the primacy effect because it provides a possible explanation of how the effect may arise through the interaction of real neurons.

# References

> Anderson, J. R., Bothell, D., Lebiere, C., & Matessa, M. (1998). An integrated theory of list memory. Journal of Memory and Language, 38(4), 341-380. PDF
>
> Botvinick, M. M., & Plaut, D. C. (2006). Short-term memory for serial order: a recurrent neural network model. Psychological review, 113(2), 201. PDF
> 3 votes

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Tags: cognitive-psychology, memory, cognitive-modeling
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# Question
Title: Should questions in psychology always be objective questions?
Is it correct that a subjective question is not a psychological question? I.e. for a question to be psychological, must it be an objective question? E.g. a question about an objective probability instead of just what you like or don't.

# Answer
There are many granulations of the objective-subjective distinction. The most objective would be the behaviorism which says it is meaningless to reason about anything except how environmental stimulus leads directly to observed behavior. This camp was popular in psychology during the time of B.F. Skinner, but now is seldom followed by people outside of biology.

In modern treatments of cognitive psychology, the scientists attributes internal private states to the people they study. These states are subjective, but are assumed to be (to some extent) analogous across individuals. The scientist then collects statistics about these internal states from many different individuals, this is one of the reasons why some view psychology as a 'statistical science'. Conducting a survey of people's subjective states is perfectly admissible methodology in this view.

The subjective experience is taken most seriously in clinical psychology. When working in this field, it is very important for the scientist (or doctor) to be very familiar with the fact that the patient's subjective experience of the world around them could not be very dissociation from what we typically view as objective reality.
> 6 votes

# Answer
Your question potentially raises philosophical questions, but for it to have meaning, there are several definitional issues.

### What is a psychological question?

Presumably a psychological question is any question that concerns the domain of psychology.

There are many criteria that could be used to evaluate whether it is a scientifically interesting question in psychology. Failure to be interesting, does not stop it from being psychological. A few criteria might include:

* **Generality:** Interesting psychological questions tend to have a generality of cover. Thus, they often apply to many situations and contexts.
* **Importance:** Importance can be pure or applied. Important pure questions tend to interlink with many other aspects of psychology (e.g, fundamental importance of learning, cognition, etc.). Applied questions tend to be important if the answer is likely to help people live better, healthier, more productive lives (e.g., research on work, education, depression, etc.).
* **Clarity**: An interesting question will be clear and answerable. Thus, the meaning of the question should be clear or at least operationalised to be clear.
* **Gap:** More broadly, if you are doing research yourself, then you want their to be a gap in the literature (i.e., the answer to the question is not yet known). I discuss this a little more here.

You used the example of asking someone about their favourite colour. Thus, asking about how people choose their favourite colour or how stable is favourite colour over time or whether favourite colour is related to other psychologically relevant variables would be moderately interesting psychological questions (they are at least general, but perhaps not that important). Asking an individual person what is their favourite colour, is a question that concerns the psychology of one individual, but it lacks generality and is of almost know importance to the general public.

### What is a subjective question?

This could mean that the **topic of the question concerns evaluations**. For example, plenty of researchers study aesthetics, attitudes, values, which are in some sense subjective evaluations. Much research in psychology use measures that involve an element of subjectivity (e.g., personality measures, many self-report measures, qualitative ratings of performance, and so on).

This could mean that the **topic of the question is concerned with theoretical states that are not readily observable**. As @Artem has mentioned, the distinction between cognitive psychology and behaviourism readily captures this distinction, whereby cognitive psychology acknowledges both the existence and the value of theorising about internal cognitive states such as goals, cognitions, mental representations, information processing systems, etc. Much of psychology is concerned with such phenomena. Often several steps are required to move from the empirical phenomena to the theoretical concepts. Theories develop over time based on whether the theory is supported by the empirical evidence.

In both the above cases, asking such subjective questions seems both productive, interesting and legitimate.

Another way that questions can be subjective is that the **meaning of the question is not clear and thus requires subjective interpretation**. In psychological science attempts are made to link into existing literatures and use accepted terms. Clarity of the meaning of the question is important.

### What is a subjective answer?

I think this may reflect what you are referring to. A subjective answer is presumably one that depends on the person answering the question. Much of the scientific method in psychology is designed to increase objectivity in the results obtained. E.g., using established measures of constructs, linking into existing terminology and theories, following good practice in study design, performing appropriate analytic techniques, drawing reasoned inferences in light of the data and the established literature.

There is a lot to the art of psychological science. There are better methods and worse methods. There is certainly a degree of subjectivity in the scientific method, perhaps more so in psychology than in the hard sciences.

However, there are many critiques that can be made of answers to psychological questions. In general **the scientific method attempts to provide answers that are more rigorous and part of that rigour is achieved through the removal of subjectivity**.
> 5 votes

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Tags: methodology, experimental-psychology
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# Question
Title: Do victims of parental abuse and neglect become abusive or neglectful parents?
The psychology literature suggests that 'good parenting' in early childhood is a crucial helping factor in brain development of child. (e.g., see "Social Intelligence" by Goleman.)

Where people grow up without 'good parenting' do they tend to, potentially unconsciously, offer similar 'bad parenting' to their children?

By bad parenting, I mean any abusive and neglectful parenting behavior. Examples:

1. Getting drunk and beating wife in front of children (abusive).
2. Never appreciating any success of kid (neglectful).

**Does bad parenting breed bad parenting?**

# Answer
> 8 votes
Bad parenting is considered a risk factor for all kinds of disfunctional behavior. For example, childhood victimization has been found to cause a higher risk of

These are just random samples from the first page of a Google Scholar search for the term "bad parenting". This is a well researched topic, and it appears to have been shown that victims of abusive or neglective parents run an increased risk of showing abusive and criminal behavior themselves.

As for your specific question, yes, again it seems that adults that have been mistreated as children are at a higher risk to mistreat their own children. This is a consistent finding across many studies: one example, another example. Again, there are many more examples. The other risk factors, such as partner violence (i.e. adult re-victimization), teen pregnancy and substance abuse, are in turn facilitated by child victimization (see the list above).

The problem is that many studies are badly conceptualized and often do not carefully consider other influences such as personality traits and the responsibility of the child: not all children are born as the same blank slates, and a "difficult" (irascible, headstrong, energetic etc.) child will increase the likelihood that the parents use desperate attempts such as physical force to restrain it, and will as adult - and independent of being abused or not abused as a child - have a stronger tendency for anger, impatience and transgressing the borders of other people including his own children. One article analyzing methodological problems finds that of all studies on intergenerational child physical abuse published between 1965 and 2000 only ten included a control group, and of these ten only two met several other methodological standards, and of these two **one study provided evidence** for the intergenerational continuity of child physical abuse, **while the other did not**.

**So it appears that this question has not been answered to full satisfaction by current research.**

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Edit:

A great overview of the research on the effects of different parenting styles is given on pages 182-188 in Arnett, J. J. (2010). *Adolescence and Emerging Adulthood* (4th ed.). Boston: Pearson.

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Definition: Bad Parenting

Laurence Steinberg defines "bad parenting":

> So when I say bad parenting, I mean parenting that is **excessively harsh**, parenting that is **inconsistent**, or parenting that is **excessively permissive**. And lots of times kids get all three of those things together. So their parents will swing from being really, really harsh and punitive to not even caring, and being what most of us would consider to be negligent. And so those three things, the harshness, the permissiveness and the inconsistency, all have been shown to contribute to antisocial behavior during adolescence.

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Tags: developmental-psychology, parenting
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# Question
Title: How to estimate an expected effect size for a planned psychology study?
When planning a psychological study, researchers are often asked to formulate an estimate of expected effect sizes for important hypotheses in the study. This might be the expected group mean difference (e.g., Cohen's d), the correlation between two variables, the odds ratio, or any number of other effects of interest. Such estimates can then link into power analysis and sample size calculations.

However, often formulating such an estimate is a difficult task. The exact study has not been performed before. Meta-analyses may only be partially related to the hypothesis of interest. Various modifications to the design might be theorised to change the effect size from previous studies. This leads to the question of how to systematically integrate such information to formulate an expected effect.

* What is a good strategy for formulating an expected effect size in a psychological study, particularly where the study has not been performed before?
* Are there any scientific articles that attempt to elucidate best practice in effect size estimation in a psychological research context?

*Note: A student recently asked me this question, thus I thought I'd post it here to draw on the expertise of others. I will post my answer below as well, but hopefully other people add answers also.*

# Answer
> 6 votes
The purpose of reviewing the literature for effect sizes is to form an estimate of what effect size you might expect in your present study.

**Existing meta-analysis:** The principles and techniques of meta-analysis provide a good starting point for generating a predicted effect size. If a meta-analysis has already been conducted, then the estimated population mean and confidence intervals of effect sizes is a useful piece of information. In some cases there will also be a **moderator** analysis reported which tests whether the effect size varies as a function of the moderator (e.g., adults versus children; lab versus field, etc.). If your study matches one level of an influential moderator, then it may be worth weighting estimates more by the estimated effect size for that moderator.

**No existing meta-analysis:** If no meta-analysis exists or if one exists but is out of date, then you may want to perform your own meta-analysis. There are several great books on meta-analysis. I've personally found Borenstein et al (2011) to be a good introduction and Hunter and Schmidt (2004) to be useful particularly if you are interested in correlations and various corrections. Here is a link to an overview of meta-analysis. Conducting a rigorous meta-analysis for publication is a technical and resource intensive process. However, if all you want is a ball-park estimate of expected effect size for sample size and study design considerations (i.e., your not doing an explicit meta-analysis publication), then it may be more pragmatic to just do a quick informal meta-analysis. In some cases there might only be one or a few studies which are similar to your study. In this case, the meta-analysis can be very simple.

**Generalisation:** Another issue that comes up is generalisation. Students sometimes say to me that there have been no other studies like the one being conducted. This may be true, but at some level of generality this is almost always false. If a study is about a particular training program in the work place, then a meta-analysis of training in general may be informative. If the intervention has only been used with teenagers and is now being applied to adults, the meta-analysis of teenagers would be relevant. Broadly, theory should be applied to assess the likely generality of any broader research to the present study.

**Theory:** Theory is important in many respects. Theory may suggest that a particular modification to the design should increase or decrease the effect size relative to a previous studies.

**Aggregating estimates:** In general it is is important to consider how different effect size estimates should be aggregated. The more similar a previous study is to the present study, the more weight should be given to any effect size estimate. In this case, similarity requires theoretical judgement about what are the important factors that might moderate the effect. Similarly any aggregation needs to be mindful of sample size considerations where larger sample sizes will increase the precision of the estimate in any given study. Thus, at the ultra-specific, the present study may be an exact replication of a previous study. At another level, there may be meta-analytic evidence from similar studies. At an even broader level Jacob Cohen reluctantly proposed various rough rules of thumb of what to expect for small, medium, and large effects in behavioural science studies.

**Importance of uncertainty:** Another point is that you don't actually know the population effect size for your study. That's why you are doing the study. There will always be uncertainty about your effect size estimate. It can even be useful to quantify that uncertainty either using meta-analytic confidence intervals or something more ad hoc. This is analogous to the concept of a subjective bayesian prior probability on a parameter of interest. See for example, this discussion of eliciting priors from experts. Meta-analysis provides some methods for quantifying uncertainty in an effect size estimate, but this may not be entirely appropriate given that you are not trying to generalise to the variation in the whole world of effect sizes. Rather you are trying to generalise a prediction for a specific study, and you may be pooling many different pieces of information, some quantitative, and some qualitative.

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**By way of example**, I do research on personality faking. I am aware of a meta-analysis of the mean effect size of faking versus honest personality responses (e.g., perhaps around d = .6). However, I also know from previous research that the type of faking instructions makes a big difference to the expected effect size (e.g., if you tell people to fake you often get approximate d = 1.0 and if you just put people in a context with a motivation to fake you get approximate d = .3). Thus, If I were calculating expected effect size for any given study I would combine knowledge of the nature of my faking instructions with various meta-analytic estimates. I'd weight my own previous studies highly because they typically share more similar features (e.g., same personality test, similar participants, etc.) than the general literature. I'd also acknowledge the uncertainty in my estimate.

### References

* Borenstein, M., Hedges, L. V., Higgins, J. P., & Rothstein, H. R. (2011). Introduction to meta-analysis. Wiley.
* Hunter, J. E., & Schmidt, F. L. (2004). Methods of meta-analysis: Correcting error and bias in research findings. SAGE Publications, Incorporated.

# Answer
> 5 votes
If you're trying to work out a standardized effect size in order to calculate power for your study then it doesn't matter whether any studies like yours have been done. It's important to find studies using the same dependent measure so that you have an estimate of variability but evidence of the size of prior effects is less important. If you have the variance, and a bit of theory, then you can estimate the standardized effect size for the minimum effect that would be meaningful for your study. Instead of asking how big an effect others have found, you should ask yourself how big an effect matters. If it's smaller than the literature and you aim your design at the literature you'll tend to miss effects that would have been important to you. When you think about it that's kind of a waste of all of the subjects you did run in your study.

Estimating that effect size only requires a reasonable theory and sampling of the literature, and some research that can give you variability estimates for the effect

As an alternate, you could consider estimating the minimum LSD you want for the study in advance, and that can just be in the units of the dependent variable. For example, reaction time effects in a particular test might only be meaningful over 7ms and you can make that your planned LSD. Anything less isn't expected to be meaningful. Unlike your hypothesis test, you are allowed to then just keep testing as you go along until your data achieve this LSD. It will not affect alpha or power. Keep in mind, the only criteria you can use for adding subjects is the preplanned LSD, not whether you have a significant effect or not.

This has a number of benefits but the most important one is that it insures that your study can say something whether you find a significant effect or not. Having studies that can speak to both sides of an issue makes them much more valuable.

Finally, I think the difficulty of a meta-analysis is exaggerated. All research is hard and meta-analyses aren't really any more difficult. Sometimes they're easier. But more importantly, if you can't find one for the topic at hand then conducting one has great benefits. It will instantly give you an important paper in the field, expert status, and greatly inform your future research. You've got to read the papers anyway. Make notes about the results and work out their effects as you do it. Then do the meta-analysis after. You just need to extract the effect size and N. The hard part of meta is proper interpretation, not conducting it (in fact, metafor in R makes it a bit too easy). What's paradoxical is that this is MORE important for you to do if you're not statistically astute than if you are. That's because someone who just gets statistics quite well is more likely to get an accurate impression of the literature without having to do all of the meta-analysis calculations.

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Tags: methodology, statistics
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# Question
Title: Is learning facts via audio while sleeping possible?
Is there a way to make onself remember facts from an audiobook (containing for instance a list of countries and their capitals) played out loud while sleeping?

# Answer
**Theoretical perspective:** No. I don't think so. From a cognitive information processing perspective, I would hypothesise that declarative learning of new facts would not occur while sleeping. Of course, learning declarative facts while awake, but in bed (e.g., when going to sleep or when waking up in the morning) is possible, and sleep is important in consolidating what is learnt during the day. I don't think the mind is capable of the kinds of information processing required to process facts when asleep.

**Empirical perspective:** Nonetheless, my theoretical perspective above may be wrong, so it is worth while looking at the empirical evidence. I found an early review of research in Simon and Emmons (1955). The study critically evaluates 10 or so studies on sleep learning and suggests that each of them suffers from some form of methodological weakness.

Wood et al (1992) provide a more recent summary of the literature:

> When a distinguished committee of the National Research Council (NRC) recently concluded that sleep learning deserves a "second look" from experimenters (Druckman & Swets, 1988; Swets & Bjork, 1990). a distinguished sleep researcher swiftly and pungently disagreed (Webb, 1990). This controversy is not new to the field of sleep learning. Disagreement has been common since the mid-1950s, when Simon and Emmons (1955. 1956) severely criticized the methodology of existing studies and demonstrated that recall and recognition for verbal material presented during sleep do not occur when proper experimental controls are exercised.
>
> Although the views of Simon and Emmons were generally accepted, in ensuing years some empirical studies continued to report evidence of learning for verba! information presented during sleep (see reviews by Aarons. 1976; Eich, 1990; Hoskovec, 1966). Though subject to methodological criticism, their findings were buttressed by evidence from electroencephalographic and evoked potential studies that (a) transmission of auditory information to the primary auditory cortex is not different during sleep and the waking state, (b) habituation and conditioning can occur during sleep in both nonhuman animals and humans, and (c) some transfer of information to long-term memory occurs during sleep (see review by Wood, 1990). Furthermore, recent studies have suggested the existence of a cognitive unconscious (Kihistrom. 1987) and indicated that information processed outside of conscious awareness, for example, while under anesthesia (Kihistrom, Schacter, Cork, Hurt, & Behr, 1990), can be stored in memory and exert an influence on later performance. In addition, research with both amnesic and normal subjects has demonstrated the existence of implicit memory, that is, learning that does not require deliberate or conscious recollection of experience (see reviews by Richardson-Klavehn & Bjork. 1988, and Schacter, 1987).

Specifically, it appears that in their study Wood et al (1992) did not find any effect:

> This study examined implicit memory for words presented during sleep. Ten experimental subjects were presented with word pairs including a homophone and a close associate (e.g., “tortoise-hare”) and with category-instance pairs (e.g., “bird-cardinal”) during REM or Stage 2 sleep and tested immediately afterward. Twelve control subjects underwent the same procedure while awake. Unlike the controls, subjects in the sleeping condition showed no learning effects on the implicit memory tasks. Recall and recognition were observed in a few cases, but only when presentation was immediately followed by arousal.

### References

* Simon, C. W., & Emmons, W. H. (1955). LEARNING DURING SI. EEP?. LEARNING, 52(4), 1055. PDF
* Wood, J. M., Bootzin, R. R., Kihlstrom, J. F., & Schacter, D. L. (1992). Implicit and explicit memory for verbal information presented during sleep. Psychological Science, 3(4), 236-239.
> 6 votes

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Tags: learning, sleep
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# Question
Title: What brain skill does Nonogram (Picross) games develop?
I've been playing Nonogram Picross a lot lately. I really like it and you can always find a harder challenge but I would hate to waste my time for nothing.

**What brain skill does Nonogram (Picross) develop?**

# Answer
> 1 votes
I could not find any examples in the literature where the game has been explicitly studied for brain training purposes. I should also confess that I don't know a lot about the specific game. However, based on general knowledge of the skill acquisition literature, I would predict the following:

Playing the game should develop your skills in Nonogram Picross. If you prefer the brain-terminology, you could say that playing Nomogram Picross develops the "brain skill" of playing Nonogram Picross. In some senses any human skill involves the brain.

I don't imagine that playing the game would improve your cognitive capacity in any general way. However, it might make you better at playing other similar games. Skill acquisition tends to be fairly domain specific.

If you are looking for advice, play the game if you get intrinsic enjoyment from it. If you want to improve your functioning in some other domain of life, then practice and learn skills more relevant to that other domain of life.

You may find it helpful to read another question on brain training on this site for more links to literature on evaluations of brain training.

# Answer
> 3 votes
Psychological video game research began in earnest in the early 1980s "as a reaction to Surgeon General C. Everett Koop’s provoking statements about the adverse effects of video games." (Mulligan, 2008) From then on, video game research tried to understand wether playing violent video games increased aggressive behavior. For 20 years, violence was the only focus for psychological science, and understanding this became even more urgent in the public mind, when it became known after the Columbine High School massacre, that the assailants had "trained" for their attack by playing *Doom*.

In 2003 a paper by **Green and Bavelier** published in Nature had a revolutionary impact on computer game research. Green an Bavelier found that playing action video games increases visual attention capacities. Since their article, a multitude of papers has been published, documenting research into the effect of computer game play on cognitive abilities.

A research paper title illustrating this new trend in computer game research is "Mom, let me play more computer games: they improve my mental rotation skills" (Cherney, 2008). It has been suggested, that playing action computer games would benefit women (Spence, Yu, Feng & Marshman, 2009) or older people (Kato, 2010) to increase their performance in certain cognitive skills and, for women, counter the cultural gender bias in learning these skills (which favors men), or, for older people, to counter the effects of aging. Spence and Feng (2010) emphasize the positive effect computer games can have on those skills (see the list below) that are important for success in science, technology, engineering, and mathematics:

> From an educational perspective, spatial cognition is essential for successful problem solving in science, technology, engineer- ing, and mathematics (STEM) education and occupations (Terrell, 2007). Spatial abilities are necessary for a wide range of job- related skills, such as solving mathematical problems (especially those involving geometry); visualizing the consequences of actions in surgery; designing structures such as bridges, buildings, and aircraft; constructing flowcharts and other representations of com- puter programs; creating and interpreting charts, graphs, diagrams, maps, and engineering drawings; and so on. Excellence in STEM fields is strongly correlated with spatial ability (Wai, Lubinski, & Benbow, 2009), and spatial skills are associated with performance in mathematics and science courses (Delgado & Prieto, 2004) and standardized tests (Casey, Nuttall, Pezaris, & Benbow, 1995), as well as the choice of mathematics and science courses in college (Casey et al., 1995).

A summary of the research is given in this meta analysis by Spence and Feng (2010). They give a table that details which games train which skills. I'll not give the complete table here, but in summary:

**Action Games** train:

* sensory detection
* attention (capture, selection, switching, etc.)
* visuomotor coordination
* processing speed
* working memory
* spatial cognition

**Maze and Puzzle Games** train:

* long term memory
* spatial cognition
* analytical thinking

I don't know Picross, but if it is a puzzle game (as your link suggests), it should increase mostly the three cognitive abilities mentioned above, and, to a lesser degree, sensory detection, attention (specifically capture and divided attention), and working memory. The article by Spence and Feng (2010) provides a good overview and is a great starting point for further research.

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Literature:

* Cherney, I. D. (2008). Mom, let me play more computer games: They improve my mental rotation skills. Sex Roles, 59, 776-786. doi:10.1007/s11199-008-9498-z
* Green, C. S., & Bavelier, D. (2003). Action video game modifies visual selective attention. Nature, 42(6939), 534-537. doi: 10.1038/nature01647
* Kato, P. M. (2010). Video games in health care: Closing the gap. Review of General Psychology, 14, 113-121. doi:10.1037/a0019441
* Mulligan, M. (2008). Exploring mood management via exposure to a massively multi-player online game (Doctoral dissertation). Retrieved from the Florida State University Electronic Theses, Treatises and Dissertations database. (ETD No. etd-04112008-154329) \[http://etd.lib.fsu.edu/theses/available/etd-04112008-154329/\]
* Spence, I., & Feng, J. (2010). Video games and spatial cognition. Review of General Psychology, 14(2), 92-104. doi:10.1037/a0019491
* Spence, I., Yu, J. J., Feng, J., & Marshman, J. (2009). Women match men when learning a spatial skill. Journal of Experimental Psychology,: Learning, Memory, and Cognition, 35, 1097-1103. doi:10.1037/a0015641

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Edit re Jeromy's comments below (post doi to the interface at http://www.doi.org to find the articles):

There have been a few studies showing increased performance in a non-game task after training with a computer game designed specifically for this ability (so called "serious games"). Examples are games improving treatment adherence in medical patients, surgical skill in doctors etc. (overview in Kato, 2010, see above; or doi:10.1542/peds.2007-3134), training multitasking in a supermarket with stroke patients (doi:10.5014/ajot.63.5.535). But you have asked for transfer from a generic (action or puzzle) computer game to a non-related real-world task.

(doi:10.1080/001401300184378) have shown that the treatment group (trained with a computer game) was "less affected by concurrently performed interference tasks", which the authors attribute to an increased ability to perform under high cognitive load. (doi:10.1111/j.1467-8535.2006.00593.x) found that "gameplaying was more effective than drills in promoting maths performance, and cooperative \[vs competitive\] gameplaying was most effective for promoting positive maths attitudes".

As always, I have methodological objections agains both studies, and I believe you will have, too. (doi:10.3389/fpsyg.2011.00226) gives an overview of transfer studies and their results -- and methodological shortcomings.

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Tags: neuroscience, learning
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# Question
Title: How can psychometry measure the very high IQ's in adults?
From Wikipedia's page on **Mental age**, we learn that:

> Originally, the differences between mental age and chronological age were used to compute the intelligence quotient, or IQ. This was computed using the ratio method, with the following formula: mental age/chronological age * 100 = IQ. No matter what the child's chronological age, if the mental age is the same as the chronological age, then the IQ will equal 100.\[4\] An IQ of 100 thus indicates a child of average intellectual development. For a gifted child, the mental age is above the chronological age, and the IQ is higher than 140; for a mentally retarded child, the mental age is below the chronological age, and the IQ is below 70.

In this way, precocious children can get exceptionally high scores (e.g. scores above 160, s.d. 15), even if they answer correctly only a fraction of the total number of questions, provided the test is sufficiently hard in comparison with their actual chronological age. However, I am not aware of any tests for adults that discriminate accurately above the threshold of IQ $\sim$ 160 - their accuracy is even less than 4 s.d., taking into account a ceiling effect.

* **How can psychometry assess an IQ of 170 or 180 in adults when the rarity of such scores is 1 in several millions?**
* **Can the IQ scores of exceptionally and profoundly gifted children be extrapolated into adulthood?**
* **Is it true that that a profoundly gifted child with an IQ of 170 would score better than 99.9998% of the general population?**
* **It seems that two different definitions of IQs are used here: is there a correlation between them?**

# Answer
> 8 votes
## General points about IQ measurement

IQ scores are standardised scores typically with a mean of 100 and a standard deviation of 15. As Ben Cole notes, IQ scores are typically normed relative to age groups in children, and then normed relative to the adult population for adults.

## Can the IQ scores of exceptionally and profoundly gifted children be extrapolated into adulthood?

IQ scores correlate very highly over time. That said, correlations decrease as (a) the period of time between testing sessions increases, and (b) the earlier the age of initial testing (e.g., testing at 2,3, 4, 5 years of age, etc.). Presumably greater periods of cognitive change have the potential for greater individual differences in that change, and such greater potential for reductions in the correlation over time.

Here's an extract from a major review of IQ testing and intelligence relevant to stability that reiterates these points with sources (Neisser et al, 1996):

> Stability. Intelligence test scores are fairly stable during development. When Jones and Bayley (1941) tested a sample of children annually throughout childhood and adolescence, for example, scores obtained at age 18 were correlated Y = .77 with scores that had been obtained at age 6 and r = .89 with scores from age 12. When scores were averaged across several successive tests to remove short-term fluctuations, the correlations were even higher. The mean for ages 17 and 18 was correlated r = .86 with the mean for ages 5, 6, and 7, and r = .96 with the mean for ages 11, 12, and 13. (For comparable findings in a more recent study, see Moffitt, Caspi, Harkness, & Silva, 1993.) Nevertheless, IQ scores do change over time. In the same study (Jones & Bayley, 1941), the average change between age 12 and age 17 was 7.1 IQ points; some individuals changed as much as 18 points.

So, in summary exceptionally gifted children will tend generally to be highly intelligent adults. However, there are a few notes of caution:

1. Any IQ measurement has error. Thus, the IQ measurement is only an estimate of the individual's true IQ. For standard IQ tests, the size of this measurement error is greater as you move towards the tails of the distribution of IQ scores, such as is the case with the very gifted.
2. There is an effect known as regression toward the mean. This says, among other things, that when two measures are imperfectly correlated, extreme scores on one variable will tend to be relatively less extreme on the other. This can be explained both in terms of measurement error (i.e., those identified as having a 160 IQ might just have got luck on the test) and in imperfect correlation of latent IQ over time. Thus, in general if you identify a sample of very high IQ children and select them, you may find that there average IQ drops at a second time point. They'll still of course be measured as very intelligent on average.

### Is it true that that a profoundly gifted child with an IQ of 170 would score better than 99.9998% of the general population?

A child's IQ is defined relative to a population of children of the same age as that child, and not the general population.

Based on a definition of IQ as a normative score, you get the following percentiles using R:

```
> iq <- c(100, 115, 130, 145, 160, 170)
> percentile <- 100 * pnorm(iq, 100, 15)
> cbind(iq, percentile=round(percentile, 6))
      iq percentile
[1,] 100   50.00000
[2,] 115   84.13447
[3,] 130   97.72499
[4,] 145   99.86501
[5,] 160   99.99683
[6,] 170   99.99985

```

Thus, yes, you are correct in a theoretical sense that a true IQ of 170 by definition implies that that individual has an IQ greater than 99.99985% of the relevant normative population.

However, the reality is that you never measure true IQ. You only get responses to an individual on a test. And this measurement is made with error, and this error in measurement is typically greater at the high end. Thus, you get a measure with confidence intervals or some form of bayesian estimate of IQ. Furthermore, there is also error in measuring population norms as well. Thus, if you want to be more precise in your description of what a test says about an individual's IQ, then you need to specify a range on that individual's IQ, and this range would be larger at the high end, because intelligence tests are not typically optimised to the high end and normative estimates of IQ at the high end would be less precise.

### References

* Neisser, U., Boodoo, G., Bouchard Jr, T. J., Boykin, A. W., Brody, N., Ceci, S. J., ... & Urbina, S. (1996). Intelligence: Knowns and unknowns. American psychologist, 51(2), 77. PDF

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Tags: intelligence
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# Question
Title: Facet versus scale prediction of Big 5 personality
**NEO facets and scales:** The NEO model of personality has 5 scales (i.e., extraversion, neuroticism, agreeableness, openness, and conscientiousness). For each scale there are 6 facets (e.g., neuroticism has anxiety, hostility, depression, self-consciousness, impulsiveness, and vulnerability to stress). See here for a list of the 30 facets and how they relate to the 5 scales.

**Incremental prediction:** I am interested in the degree to which the 30 facets predict important real-world outcomes over and above the big 5 scales. Examples of important outcomes might include financial success, life satisfaction, health outcomes, longevity, job performance, career success, marital satisfaction, criminality, and so on. While each of these outcomes would be interesting in itself, I'm particularly interested in any general claims that can be put forward regarding the incremental predictive validity that is obtained from using facets rather than scales.

**Statistical baseline:** I take a few points as self-evident. There is a difference between in sample prediction and true population prediction. The true population regression equation can not be worse for the facets than the scales. The facet level prediction could mirror the scale prediction merely through an appropriate set of regression coefficients (i.e., some form where facets are in some sense equal within a scale, adding up to the scale effect).

I also take it as self-evident that the population prediction would be at least a little bit better with facets. It seems implausible that the pattern of regression coefficients required to replicate the scale prediction would necessarily be exactly match the best population prediction model. However, there is still the question of what the size of the increase is, and how big the increase in prediction is relative to the prediction achieved by the scales.

**Methodological challenges:** There are also several issues around estimating the size of the incremental prediction of facets relative to scales. Adding an additional predictor increases sample variance explained even when the predictor has know incremental prediction in the population. Thus, procedures that compare sample r-squared of scales versus facets prediction models would be biased. Models that use a data driven variable selection procedure like step-wise regression to select an optimal subset of predictors would also be biased. The size of this bias would be greatest in smaller samples.

Thus, I'm particularly interested in studies that have accounted for these methodological challenges. For example, a good study might have (a) a large sample of 1000+ participants in order to generate robust results, and (b) a statistically valid procedure for estimating population r-squared for facet and scale predictor models (one possibility would be to estimate the model in half the sample and evaluate in the other half, although many other cross-validation procedures are possible).

Thus, **my questions**:

* What is the incremental prediction of the 30 facets over and above the big 5 scales on important psychological outcomes?
* In particular, how and to what extent have studies dealt with the methodological issues related to performing this comparison?
* In totality, is the incremental prediction at the facet level sufficient to justify the added complexity to thinking and theorising?

# Answer
Several studies have been conducted comparing facets versus factor prediction (e.g., Paunonen and Ashton, 2001; Mershon and Gorsuch, 1988; Ashton et al, 1995; Dudley et al, 2006; Ekehammar & Akrami, 2007).

Many of these studies have found substantial incremental prediction of facets over factors. However, there are several potential methodical issues that may potentially arise: (a) overcoming biased estimates of R-square particularly when comparing analyses with facets versus factors where more predictors increases the bias; (b) overcoming issues of multiple comparisons when there are many facets that can be compared to factors; (c) some studies only have small sample sizes.

By statistical definition, the population r-square for a factor model is less than or equal to the population r-square for a facet model where factors are defined as a linear function of the facets. Nonetheless, I have not yet read any systematic studies that have provided an unbiased estimate of population r-square in factors versus facets. Having read all the above articles, my hypothesis would be that I would expect an increase in r-square of around 5 to 20 percent, but that's just a rough sense.

### References

* Ashton, M. C., Jackson, D. N., Paunonen, S. V., Helmes, E., & Rothstein, M. G. (1995). The criterion validity of broad factor scales versus specific facet scales. Journal of Research in Personality, 29(4), 432-442.
* Dudley, N. M., Orvis, K. A., Lebiecki, J. E., & Cortina, J. M. (2006). A meta-analytic investigation of conscientiousness in the prediction of job performance: examining the intercorrelations and the incremental validity of narrow traits. Journal of Applied Psychology, 91(1), 40.
* Ekehammar, B., & Akrami, N. (2007). Personality and prejudice: From Big Five personality factors to facets. Journal of Personality, 75(5), 899-926.
* Mershon, B., & Gorsuch, R. L. (1988). Number of factors in the personality sphere: Does increase in factors increase predictability of real-life criteria?. Journal of Personality and Social Psychology, 55(4), 675.
* Paunonen, S. V., & Ashton, M. C. (2001). Big Five factors and facets and the prediction of behavior. Journal of personality and social psychology, 81(3), 524-539.PDF
> 3 votes

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Tags: personality, statistics
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# Question
Title: Deception and nose touching - does it work for things that are about to be said in prepared speeches?
I'm not sure if nose touching is a scientifically-validated signature of deception or internal conflict. For the purposes of this question I would assume that it's fairly common knowledge in psychology that people touch nose or cover the mouth when saying something part of them does not believe to be true.

If nose touching is encountered in a regular,spontaneous conversation, then it may be deduced that the statement that the person just made is untrue (or the person does not really believe it). For example: "I can easily make money on the stock market". If such statement is followed by a nose touch, I can assume that the person is at least partially unsure about the content of the statement.

Now, when I'm watching prepared talks, like on Ted.com, the following question arises: If a person has prepared a speech in advance,rehearsed it and is now delivering a prepared speech, does nose touching have any "predictive component" for deception? In other words, **if a person touches a nose during a prepared speech, is it a sign of deception/internal uncertainty that just happened or one that is about to happen?**

I know that there are fMRI studies that found some actions can be predicted x milliseconds in advance, and I'm interested if nose touching is one of things that can predict something that is about to happen, not indicate something that just happened.

# Answer
You wrote:

> For the purposes of this question I would assume that it's fairly common knowledge in psychology that people touch nose or cover the mouth when saying something part of them does not believe to be true.

Avoid make assumptions like this. This is not common knowledge, and in fact it is not even true.

Vrij et al. (2010) discuss the literature on non-verbal lie detection and conclude:

> The meta-analyses that have been published to date have made clear that there are no nonverbal and verbal cues uniquely related to deceit. In other words, reliable cues to deception akin to Pinocchio’s growing nose do not exist (DePaulo et al., 2003; Masip et al., 2005; Sporer & Schwandt, 2006, 2007; Vrij, 2005)

Vrij & Granhag (2007) mentions "touching the nose" as an example of a non-verbal cue to deception found in a police interrogation manual, Gordon & Fleisher (2002). They also review 5 other police interrogation manuals which *don't* mention it as a cue to deception. In my brief lit search, I couldn't find any psychology papers which discuss touching the nose as a reliable cue to deception.

After a brief look at Gordon & Fleisher (2002), it is clear to me that their methods are pseudoscientific, full of ad-hoc reasoning. Judge for yourself:

> There appears to be a link between deception and the nose. Perhaps it is because the nerve network for emotions, to a large extent, evolved from our neural networks involved in smelling \[26\]. The sense of smell was primitive man's fundamental survival mechanism. **Touching or pinching the nose is a reliable gesture of disbelief \[4\].** The nonverbal message appears to be "it stinks' (Figure 9.17). If you are talking and the listener pinches his nose, he is nonverbally communicating that he thinks what you are saying stinks. If he is talking and pinching his nose, he thinks what he is saying stinks.

Oh, but what's that reference they cite? Surely that must shed some light on this. Diligent readers will scan to the bibliography only to find that *they are citing a previous version of the same manuscript!* Yes, you heard right: a recursive citation. Not exactly the most reliable source.

Vrij & Granhag (2007) suggest:

> Since cues akin to Pinocchio's nose do not exist, lie detectors will fail in their task if they just look for such cues. Rather, interview techniques need to be employed, for example, to control for individual differences between individuals.

# References

> Gordon, N. J., & Fleisher, W. L. (2010). Effective interviewing and interrogation techniques. Academic Press.
>
> Vrij, A., & Granhag, P.A. (2007). Interviewing to detect deception. Offenders' memories of violent crimes, 32, 279.
>
> Vrij, A., Granhag, P. A., & Porter, S. (2010). Pitfalls and opportunities in nonverbal and verbal lie detection. Psychological Science in the Public Interest, 11(3), 89-121. PDF
> 7 votes

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Tags: cognitive-psychology, behaviorism, deception
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# Question
Title: How to compare linear and categorical models of perceptual comparisons?
Say I have a confusion matrix of perceptual similarity data for stimuli drawn from an underlying continuous spectrum. Participants also learned to categorise these stimuli such that the spectrum is evenly divided into two categories. I want to test whether the observed confusion matrix shows a better fit to either a continuous or a categorical model. One approach I have considered is to create a hypothetical confusion matrix for linear and categorical models (see below) and correlate these with the observed confusion matrix.

Note: Similarity values, 1 = identical, 0 = dissimilar

However, I’m not sure how to compare the degree of fit for each model. One idea is to take the partial correlation to measure how well the confusion matrix correlates with the categorical model after the correlation between the linear model and the data has been accounted for. This approach seems to have good psychophysical validity (since any categorical process would function in addition to a linear sensory one), however I’m concerned that the linear and categorical models are highly correlated (here at 0.83) and so any partial correlation approach would not be valid. Including more stimuli near the category boundary would probably go some way to decorrelating these models, however I’m wondering if there is a more sensible approach to figuring this out (but not orthogonalising the models)? Any leads appreciated.

# Answer
> 5 votes
This sounds a lot like tests of categorical perception done in psycholinguistics. Categorical perception states that people perceive phonemes categorically, even though the acoustic signal varies continuously.

For example, the phonemes $/b/$ and $/p/$ differ on only one acoustic feature: voice onset time. Using computer synthesized speech, one can experimentally manipulate the voice onset time along a continuous dimension. In a prototypical experiment, subjects are asked to identify each sound as a $/b/$ or $/p/$. If perception were continuous, you might expect that the proportion of $/b/$ responses varies linearly with the voice onset time-- but it doesn't. As you can see in the red line, there is a sharp drop around 20ms in which people perceive everything to the left as $/b/$ and everything to the right as $/p/$.

Another way to see this is to plot discriminability (blue line). Here, participants are presented two stimuli from adjacent VOT bins and asked to judge which one matches a 'target' stimulus. Generally, people perform near chance at discriminating between the two phonemes *unless* the two stimuli cross the VOT boundary. Again, if perception were linear, you might expect a straight blue line rather than a peaked one.

Most researchers will use t-tests or ANOVA to test for differences of between and within category discrimination. For instance, one might conduct a series of t-tests on discriminability to show that only when stimuli cross the VOT boundary can subjects reliably discriminate them.

For an example of these tests in practice, see Morford et al. (2008). Note that some researchers have found conflicting results when using different dependent measures. For example, Massaro & Cohen (1983) asked participants to make continuous judgments of stimuli and found no evidence of categorical perception.

Another alternative might be to find the best fitting line and the best fitting sigmoid curve, and compute the Bayesian Information Criterion for each. The one with the lower BIC is the preferred model. For regression analysis, BIC can be calculated as

> $BIC = n\log(\frac{RSS}{n}) + p\log(n)$

where n is the number of data points in the model, p is the number of free parameters, and RSS is the residual sum of squares.

The drawback of using BIC is that it only tells you something about *comparative* model fit. If both linear and sigmoidal models were a bad fit for the data, BIC would not tell you that.

> Massaro, D. W., & Cohen, M. M. (1983). Categorical or continuous speech perception: A new test. Speech Communication, 2(1), 15-35. PDF
>
> Morford, J. P., Grieve-Smith, A. B., MacFarlane, J., Staley, J., & Waters, G. (2008). Effects of language experience on the perception of American Sign Language. Cognition, 109(1), 41-53. PDF

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Tags: categorisation, similarirty
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# Question
Title: What is the status of evolutionary psychology in academia today?
Having an interest in human psychology (but no formal training) I decided to take Coursera's Introduction to Psychology as a Science. Here's a snippet from an introductory lecture (it requires signup, so I'll paste the transcription):

> Statement: "Much of human behavior is instinctive."
>
> Answer: "No, we have very few instinctive behaviors. There are some reflexes that young infants have, like for example the reflex to suck if you put something in their mouth or if you tickle the bottom of their feet, their toes will spread out. Those are reflexes that go away as the child gets older. We certainly have genetic predisposition to do things in a certain way. But, instinct, species specific behaviors that lower animals have, are very rare in human behavior."

This emphatic assertion really surprised me. It was my understanding that -at least at some degree- the fundamentals of evolutionary psychology had influenced "traditional psychology" over the years (not as explanation of every human behavior, sure, but certainly more than to explain the sucking reflex).

So here is the question: **has evolutionary psychology found its place in universities (syllabus, articles, ...) or is it pretty much ignored in academia?**

# Answer
> 7 votes
Academic psychology has been, since the middle of the nineteenth century, first and foremost *empirical*. Since the beginning of the twentieth century, academic (empirical) psychology is mostly *experimental*. For one hundred years, the basis of psychological research has been to derive theories from popular opinion or any other relevant source, derive hypotheses from these theories, and to test these hypotheses in an experiment. For example, it has been the popular opinion that playing video games "makes" children and adolescents aggressive, antisocial and violent. Psychologists have tested this hypothesis by observing the level of aggression in a random group of children after they played an action video game, compared to the level of aggression of a random (control) group of children after they played a non-action video game. Whatever phenomenon psychologists are interested in, this is the basic methodology.

In psychology, the theory of evolution is just a theory. It is neither better nor worse than other theories. For evolutionary theory -- or any other theory -- to be relevant to psychology, it has to produce hypotheses that can be tested empirically, preferably in a laboratory (i.e. a controlled) experiment.

There are many psychologists today who look at all kinds of human behavior and experiences from an evolutionary perspective, derive theories from this perspective, and test these hypotheses. This research is commonly taught in the relevant courses in universities. For example, in a lecture on developmental psychology, the lecturer will routinely present psychoanalytic, behaviorist, humanist, systemic, context, domain-specific, evolutionary, and other theories and research on how human beings develop psychologically from conception through childhood, adolescence and adulthood to old age and death, and he will try to elaborate more or less neutrally on the strengths and weaknesses of these theories, and their methodological shortcomings.

In short, evolutionary psychology has its place in academic psychology, although, from my observation, it is already a bit dated and had its high point maybe in the last half of the twentieth century. Today, neuropsychology is the height of fashion ;-)

*Source: Personal observation (I work at a university)*

# Answer
> 8 votes
*This is a bit of a quick answer and hopefully others will provide a more comprehensive response.*

The number of reflexes that exist in humans is arguably a separate issue to the support for evolutionary psychology. The answer below focuses specifically on the support for evolutionary psychology in academic psychology.

Almost all researchers in psychology would agree that **evolutionary processes have shaped what it means to be human**. A good example of a well-developed theory is ACT-R, which provides a model of cognition. An underlying assumption of the theory is that the nature of the underlying structure of cognition has evolved to minimise the consumption of computational and biological resources (although you're better off reading ACT-R material directly to understand how they describe the interface of genetic and environmental adaptation, e.g., Anderson 1991). This still leaves many issues regarding how to conceptualise human nature and the extent of human plasticity.

**However, "just so" arguments made in the name of evolutionary psychology are generally not respected in academic psychology**. For example, Someone might say that women are better at multitasking because throughout evolution men's behaviour has required singularity of purpose in hunting and mate seeking, whereas women have had to juggle competing tasks of child rearing, looking after the camp, and so on. Of course, that's all rubbish. I just made that argument up out of nothing. Such an argument takes an observation, possibly not even true in the first place, and then seeks to find some vaguely plausible evolutionary story to justify it. It's a "just so" argument. You can see further discussion of critiques of evolutionary psychology here.

### References

* Anderson, J. R. (1991). Is human cognition adaptive. Behavioral and Brain Sciences, 14(3), 471-517. PDF

# Answer
> 2 votes
One area in which, I believe, evolutionary psychology gets a fair degree of respect is in social psychology, and in particular in the study of cooperative behavior.

You might wish to check out

> Axelrod (1981) The Evolution of Cooperation
>
> Nowak (2006) Evolutionary Dynamics: Exploring the Equations of Life

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Tags: evolution
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# Question
Title: How to design research participant recruitment flyer to maximise participant response?
I often supervise student research projects. Often these projects involve recruiting participants by placing one page flyers in strategic locations. The most common scenario is that the flyer is targeted at university students, there may be some small financial reimbursement for their time, and the study might involve spending an hour or so in lab.

When writing such a flyer, there is a balance between making participation sound like a worth while thing to do, but at the same time being ethical and accurate in describing what the study involves.

Thus, while I have a bunch of tips and tricks for writing such materials, I wasn't aware of any particular material that I could provide to research students to get started.

* **What is best practice in participant recruitment flyer design?**
* **What is a good repository of examples of good participant recruitment flyers?**
* **What are some good online resources outlining tips for creating a participant recruitment flyer?**

I'd also be interested in materials about the surrounding context (e.g., flyer placement; streamlining the process between reading a flyer and participation).

# Answer
Not exactly an answer to your question, but some thoughts on why we *don't* use flyers.

There is a lot of research going on at our university that involves recruiting participants. From psychology to medicine and economics, everybody vies for the time of the several thousand students. Then there are all those flyers for parties, political initiatives, religious get-togethers etc. etc. On top of this information overload, most students are extremely short of time and mental and emotional energy. Studying here is hard, and students don't want to sit in a lab, when they have the time to not sit over their books.

Our department has the most success at recruiting participants with setting up a small screened area inside the refectory/cafeteria (where the students eat their lunch), standing in front of the entrance, approaching everyone, and testing them then and there. If we cannot test them in the cafeteria, we still approach them there and try to arrange a date for a lab test. We also offer sweets *with the recruitment* (they're in a small tray and offered when we approach the person).

Maybe that gives you some ideas.
> 5 votes

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Tags: methodology, experimental-psychology, sampling
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# Question
Title: How to interpret HLM analyses looking at work group and individual worker effects?
Liden et al (2004, PDF) is an example of a study examining employees in work groups in an organisation. Thus, measures are obtained of both individual workers and of the work groups that they belong too. The data is analysed using multilevel modelling (or what the paper calls HLM).

* How can the HLM results in the paper be explained in a way that is meaningful for someone with only a basic level of statistical knowledge?
* What resources could help someone with only a basic level of statistical knowledge understand the paper?

---

***Note:** The above questions are based on an email I received asking about how to interpret the results of Liden et al (2004). I'll probably add an answer. But I thought others might also have answers, and that the answer might be relevant to others.*

The abstract:

> Social loaﬁng was investigated by testing a multilevel model among 23 intact work groups comprised of 168 employees representing two organizations. Results demonstrated that as hypothesized at the individual level, increases in task interdependence and decreases in task visibility and distributive justice were associated with greater occurrence of social loaﬁng. At the group level, increased group size and decreased cohesiveness were related to increased levels of social loaﬁng. Of particular interest was the ﬁnding that group member perceptions of perceived coworker loaﬁng was associated with reduced social loaﬁng, opposite of our predictions. We suggested that this unexpected ﬁnding may provide evidence of a social compensation effect.

### References

* Liden, R. C., Wayne, S. J., Jaworski, R. A., & Bennett, N. (2004). Social loafing: A field investigation. Journal of Management, 30(2), 285-304. PDF

# Answer
> 1 votes
## Tutorials on HLM

Ultimately the paper assumes that you understand HLM. HLM analysis is a bit more complex than multiple regression because it deals with multiple levels of variance.

There are various tutorials and readings that can bring you up to speed:

* Woltman et al (2012) in particular provide a quantitative psychology tutorial.
* For a textbook treatment you could check out Raudenbush and Bryk (2002).

# Interpreting Liden et al (2004)

The study uses a bunch of variables some at the individual level and some at the group-level. There are 168 participants in something like 23 groups (although there may have been some deletion of groups with insufficient interrater reliability).

The study reports individual and group level correlation matrices of these variables. Group level measures are presumably the mean of the individual group members.

The study often mentions $r\_{wg}$, ICC(1) and ICC(2). These are all indices of within group rating agreement. A general assumption of multilevel research is that if you are going to aggregate individuals into group level scores, then individuals within groups should be more similar to each other than across groups. Thus, these three indices are used to justify aggregation into groups. See LeBreton and Senter (2008) for a discussion of how interrater agreement indices can be used in organisational research.

**The main HLM** predicts social loafing from both group and individual level variables. They estimate that 49.99% of the variance in social loafing can be explained by group differences. So in summary, some groups engage in more social loafing than others. Nonetheless, there is still variation in social loafing within groups (e.g., loafers in non-loafing groups, and non-loafers in loafing groups).

The authors then go on to analyse what predicts variation within groups using individual level measures. In Table 3 shows a model with four predictors. For example, it shows that individuals with more task interdependence are more likely to engage in social loafing as indicated by the positive coefficient and the significant p-value. The authors note that they were able to explain 21.81% of the within-group variance in employee social loafing.

Then they report a group level analysis which predicts the variation in average social loafing in groups from other group-level variables. They find for example that larger, less cohesive groups have more group level social loafing. Not surprising, they also find that groups which perceive that others engage in social loafing do in fact engage in more social loafing. They find that 30.72% of the variance in group level variance is explained by these group level variables.

The HLM approach is thus a nice fit to studying workers who are situated in different work groups. You are able to examine both individual and group-level effects. This is consistent with a theory of behaviour in the workplace that says that behaviour is influenced by both individual characteristics as well as group dynamics.

### References

* LeBreton, J. M. & Senter,J. L. (2008). Answers to 20 Questions About Interrater Reliability and Interrater Agreement. Organizational Research Methods,11, p 815-852.
* Woltman, H., Feldstain, A., MacKay, J. C., & Rocchi, M. (2012). An introduction to hierarchical linear modeling. Tutorials in Quantitative Methods for Psychology, 8(1), 52-69. PDF
* Raudensbush, S.W. and Bryk, A.S. (2002). Hierarchical Linear Models, Sage Publications.

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Tags: social-psychology, io-psychology, statistics
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# Question
Title: Is there a variance in acceptance of conspiracy theories by occupation?
For some time I have been very interested in the intelligent design (ID)/creationism vs. evolution debate. My parents are both medical professionals and consider themselves creationists. I have many other family members who are also medical professionals and believe in creationism. While reading webpages on the subject and other widely rejected ideas, my experience suggested that medical professionals were more likely to accept such ideas than people from other technical professions. Is there any evidence to support this?

Are people from medical professions more likely than average to accept conspiracy theories?

I did find one article that appeared to address the issue, but I could not find a free copy of it anywhere.

# Answer
> 4 votes
*I believe that a link to Google Scholar and an explanation of what it is should feature prominently on every page of this site. Many questions can be answered by a quick search there, and the rest will profit from the initial research that becomes easily possible with this tool. This explanation should include the fact that most academic institutions have access to many online journals, and that a trip to the next university library will make most of the articles readable for the general public through the computers in the library.*

To answer your question: I have no knowledge of the subject matter, but a Google Scholar search yielded several articles on the topic of conspiracy theories, some of which deal with the phenomenon from an empirical perspective.

For example, one study found, that certain personal characteristics, such as fear of unemployment, correlated with belief in conspiracy theories, while **occupational category did not correlate with belief in conspiracy theories**.

If you did further into the Google Scholar search results, you might find further, possibliy contradictory, findings and opinions on the topic.

As to your observation that many medical professionals from your family believe in creationism, and the hypothesis you deduce from this observation that maybe medical professionals are more likely to accept such ideas, I would say that this is a classic case of not recognizing a confounding variable. All the medical professionals you know come from *the same family*. Since religious beliefs are mostly acquired through familial habits, it is most likely that it is *your family*, not medicine, that correlates with belief in creationism. What defines your family and could correlate with a similar belief in other people, you might be able to recognize if you take a step back an look at your family in relation to who else lives in your country: what is your family's social status, religious tradition, ethnicity, where do you live, how are your children educated etc. etc. From all the factor that you find, you could then build a working hypothesis and test it. Some factors have been tested in the linked article, others you might find discussed elsewhere.

Have fun!

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Tags: social-psychology
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# Question
Title: Is actively trying to create insight inducing conditions effective in generating insights?
Kounios and Beeman (2009) show that many insight solutions come when one is in a relaxed state. Furthermore, positive mood helps with insight solutions.

* But practically speaking, is it wise to try and induce conditions that support insight solutions?
* Would trying to induce conditions that support insight solutions be counterproductive because of some type of meta-cognitive process in the background?

I assume that most people who have eureka moments do not explicitly seek out to have them.

### References

* Kounios, J., & Beeman, M. (2009). The Aha! Moment The Cognitive Neuroscience of Insight. Current Directions in Psychological Science, 18(4), 210-216.

# Answer
> 2 votes
This is all a fairly abstract discussion when it's independent of a particular task.

Insights are by definition those discoveries that you couldn't immediately make. Thus, they are often on the horizon of your understanding. So if you knew more to begin with, the solution may have been obvious. And ultimately solving the problem is typically the goal whether that requires and insight or not.

In general, I would assume that when people are under strong time pressure they may fall back on automated ways of doing a task. Thus, I imagine if you are trying to encourage creativity, to encourage an environment where such alternative ideas can be explored and tried. This may well relate to the issue of relaxation. If people are tense and concerned about their performance being judged immediately, they may be less able to cognitively explore the domain.

More generally, a key part of achieving insight is "incubation". Ultimately, this involves spending time on a problem, then having a break, and returning to a task.

So in summary, If you want to increase insight/creativity, I think it makes sense to do things like spending time on the task, taking breaks, creating a non-judgemental performance environment, getting input from external sources, and so on.

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Tags: cognitive-psychology, learning, problem-solving
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# Question
Title: Can hypomania be induced by just thinking quickly and variably?
Emily Pronin and Daniel Wegner have shown that fast and variable thinking induces positive affect. This is independent of thought content. Sheri Johnson has noted that the key things that might start a hypomanic/manic episide are a night of no sleep, a positive life experience, and certain drugs.

**Is it possible to clinically induce hypomania by just thinking quickly and variably?**

Note that an easy exercise to implement this would be to think of a word and then a word beginning with the previous word's letter.

**Added.** In a sense, the above exercise is "anti-meditation." Mindfulness is essentially low thought speed combined with high variability. The ideal state would be high thought speed and high variability.

### References

* Pronin, E., & Wegner, D. M. (2006). Manic Thinking Independent Effects of Thought Speed and Thought Content on Mood. Psychological Science, 17(9), 807-813.

# Answer
> 3 votes
I had a read through the Pronin and Wegner study. The study had a sample size of 144. They manipulated thought speed by getting participants to read aloud one statement after another at either half normal reading speed (slow thinking) or double normal reading speed (fast thinking). They also manipulated the content of the text being read (depressing statements versus elated statements). They seemed to find that both the content and the speed of thought manipulation seemed to yield similar increases in positive emotion, energy, feelings of power, feelings of creativity, and grandiosity.

The first issue is whether their study is replicable. I don't know the literature regarding replications, but all the effects seem plausible, and the sample size is reasonable for this kind of study.

Another issue is how the manipulation of reading speed affected the reported emotions. Perhaps the slow reading led to frustration or being annoyed.

With regards to the nature of the effect, there are questions of how long this mood induction lasts. My guess is that the effect of the mood induction would be short lived.

There is also a difference wherein mania the speed of thought is presumably internally driven whereas on this task the "speed of thought" is externally driven. The study did not measure whether this "speed of thought" continued after the external stimuli was removed. For example, does speed of thought work with an inertial principle or not such that it can be started with external stimuli and will keep going on its own. My guess would be even if such a concept of inertia existed, people would quickly return to their own typical level. Thus, I don't think such a manipulation would induce clinical levels of mania, especially not in a sample of participants who do not suffer from bipolar disorder.

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Tags: cognitive-psychology, abnormal-psychology, bipolar-disorder
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# Question
Title: Fusiform Face Area (FFA) for within class recognition?
**Is there any evidence (papers, studies, etc) that the Fusiform Face Area is used for any other type of recognition besides facial recognition?** I remember hearing or reading a long time ago that experts activated the FFA when doing within class classification in their areas of expertise, but I don't know where to find this evidence.

# Answer
> 9 votes
Yes. The idea that the fusiform face area (FFA) is domain-selective for faces is the dominant hypothesis, but a competing hypothesis is that the FFA is recruited for fine discrimination in visual stimuli of *any* type in which we are experts.

In a famous study, Gauthier et al. (1999) taught participants to categorize fictitious Greebles (see image below). Subjects were brought in for several sessions and, as their accuracy increased, activation in the FFA increased as well. The authors concluded that "expertise seems to be one factor that leads to specialization in the face area."

In another study, Gauthier et al. (2000) tested bird and car experts on identifying birds, cars, faces, and objects. They found that bird experts elicited more FFA activation for birds compared to cars, while car experts showed the opposite pattern (see below, right).

# References

Gauthier, I., Tarr, M. J., Anderson, A. W., Skudlarski, P., & Gore, J. C. (1999). Activation of the middle fusiform'face area'increases with expertise in recognizing novel objects. Nature neuroscience, 2(6), 568-573. PDF

Gauthier, I., Skudlarski, P., Gore, J. C., & Anderson, A. W. (2000). Expertise for cars and birds recruits brain areas involved in face recognition. Nature neuroscience, 3(2), 191-197. PDF

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Tags: neuroscience, perception, neuroanatomy
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# Question
Title: What psychological factors account for code readability?
Readability is often intuitively synthesized. If you see some piece of code, you just *know* whether it is readable or not. But what are actual **psychological**, scientific explanations for this?

There are readability metrics for written text, but do they apply to source code as well? For example: I believe the word superiority effect to be applicable to source code. What other effects can be found while programming, that make code readable?

I am not looking for educated opinions or examples as in here or here, but for neural correlates or a perspective from cognitive sciences.

# Answer
Using the English language, given two sentences that say the same thing, what makes one more readable than the other? Usually terseness while retaining clarity and removing ambiguity.

The exact same things make code more readable. Remove everything that doesn't add anything, but don't remove things that do add information. And avoid ambiguity.

In code, we have the advantage that we can reuse similar pieces of text and replace specific values within them. If only we could do that with books, we could save a small rainforest.

On top of terseness, we have good use of punctuation and spacing. Ever tried to read a blog piece where there are no paragraphs whatsoever? That's what it's like reading code that isn't neatly spaced out.

The psychology of this is simple. Your brain receives all sorts of hints as to what it's reading. Try taking a long piece of text and printing it out (with a serif font) without paragraphs, then without periods and commas, or maybe switch punctuation marks (? =\> ., ! =\> :, etc), then in a sans-serif font.

You'll quickly see how much you rely on your brain's instincts when you're reading. Code is exactly the same. And herein lies a problem, because some things are certainly subjective. Or rather they are a matter of habit.

If you're used to seeing underscores preceding member variables, then you move to a company where they don't do that, your brain will still expect the same hints and it will be harder to read. But to change it would mess up everybody else in the team. It would be like moving to Spain and telling them to stop using the preceding inverse-question mark because it throws you off.

Design patterns are a similar thing. If everyone knows what a Builder Pattern does, then adding Builder to a class name gives everyone a lot of information. But if I have my own Bracksfort Pattern, that information only helps me, at least until other people start to ask me, or I document it and get the community to buy into it.
> 12 votes

# Answer
This is my current area of research (I'm a Ph.D. student in computer science and cognitive science). Like you said, there are a large number of readability/complexity metrics, but very little research trying to quantify what makes a piece of code **psychologically** complex. For more information on *qualitative* studies and models, I'd highly recommend the 2001 book Software Design: Cognitive Aspects.

I've been running some experiments recently with the goal of developing a cognitive model that can "read" code like a human. The inspiration for my model largely comes from a 1995 paper by Simon Cant et. al.. In the paper, they lay down an (incomplete) foundation for a mathematical model that "chunks" small blocks of code into memory and "traces" to other parts of the program in order to resolve dependencies. I have a workshop paper titled "Cognitive architectures: a way forward for the psychology of programming" that suggests we may be able to built such a model on top of a cognitive architecture like ACT-R.

I'm currently writing up the results of one of my experiments. Once it's ready, I'll be posting about it on my blog (synesthesiam.com). In short, we had programmers of all different experience levels predict the output of 10 Python programs (each program had 2 or 3 versions). Some of them did the experiment in front of an eye-tracker, which will be another paper someday (hopefully) soon. The rest were from Mechanical Turk, and we observed interesting speed/accuracy differences that were not always in favor of the more experienced programmers.
> 7 votes

# Answer
What does "readability" mean in the context of cognitive sciences? Measurable effects of "readability" would include:

* speed of cognitive processing (how long does it take a reader to understand what the code does)
* completeness of understanding (how much of what the code does can a reader explain after reading it?)
* effort of understanding (how depleted are the reader's cognitive resources, measurable by a follow up processing power test)

It would be easy to test differently "readable" variants of the same code. Sample research can be found through a Google Scholar query. I'm too lazy to read and summarize those papers for you ;-)
> 2 votes

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Tags: cognitive-psychology, language, reading
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# Question
Title: What is the difference between psychophysics and neurophysiology?
I'm an engineering student who is doing some subjective tests.

* What are the difference between psychophysics and neurophysiology?
* Is it correct that in the latter case, we have to implant to read the brain signals?

# Answer
I'm glad you asked! The two fields are really quite different, but I think people get them confused since the terms both make reference to physics and something vaguely mental.

Psychophysics is basically the measurement of subjective percepts corresponding to physical stimuli (e.g. measuring pain thresholds or visual acuity). So here the 'physics' refers to the physical reality we're trying to represent in our mind.

Research here is almost exclusively behavioral, with the classic paradigm being to try and determine the 'just noticeable difference' between two stimuli. Signal detection theory has also been hugely influential for data analysis in the field. I find it helpful to think of psychophysics as experimental cognitive psychology at its least abstract.

Neurophysiology, on the other hand, investigates the anatomical structures underlying the brain (e.g. categorizing the types of neuron, figuring out what glia are made of). Thus the 'physics' referred to here is the physical structures underlying the brain.

Here the methodology involves various sorts of neuroimaging, tissue sampling, and other ways of probing human and animal brains at various levels of intrusiveness.

Note that these definitions paint the two fields with very broad strokes, so I'd do further research if you want to differentiate say, neurophysiology from neurobiology, but I think this suffices for the purposes of your question.

Hope that helps!
> 8 votes

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Tags: neuroscience
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# Question
Title: Why do we use 3 channel R,G,B to represent color?
I read that there're some more colors which cannot be represented by R,G,B. What is the experiment that lead people to use 3 variables R,G,B?

Can that experiment be replicated in other modals, such as what is the dimension of auditory perception, or tactile perception?

# Answer
After researching this a bit more, I believe this is actually a *biology* question, not a physics one.

The specific term I believe you're searching for is **Trichromacy**, which Wikipedia defines as:

> Trichromacy or trichromaticism is the condition of possessing three independent channels for conveying color information, derived from the three different cone types. Organisms with trichromacy are called trichromats.

Reading the Wikipedia article, it appears that the cone cells Humans (and other trichromats) come in three different variations; the different variations are sensitive to red, green, and blue light, as depicted in this image (again from Wikipedia)1:

> Normalized responsivity spectra of human cone cells, S, M, and L types

We've evolved these three cone types because red, green and blue are additive primaries, meaning most of the whole range of visible light can be represented by combinations of these colors. Quoting Wikipedia again:

> Even the four-primary technology does not yet reach the range of colors the human eye is theoretically capable of perceiving (as defined by the sample-based estimate called the Pointer Gamut\[17\]), with 4-primary LED prototypes providing typically about 87% and 5-primary prototypes about 95%. Several firms, including Samsung and Mitsubishi, have demonstrated LED displays with five or six "primaries", or color LED point light sources per pixel.\[18\] A recent academic literature review claims a gamut of 99% can be achieved with 5-primary LED technology.

I'm not sure what the experiment you're referring to was, but I doubt it would translate nearly as nicely into sound, as RGB is based on the biology of the eye specifically.

1: Attribution: Vanessaezekowitz at en.wikipedia
> 7 votes

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Tags: experimental-psychology
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# Question
Title: Is metacognition an affective, cognitive, or behavioural variable?
Is metacognition an affect or cognitive or behaviour variable ?

I want to study variation in metacognition and working memory ability level and its effect on inductive reasoning. Therefore i am trying to understand the cognitive system. I read some literature stating that metacognition is cognition awareness, which implies that it is a cognitive variable, but some say that it is an opinion about how far they can do metacognitive ability. I read about a factor analysis of the Junior Metacognitive Awareness Inventory.

# Answer
> 5 votes
It seems like there are a lot of ideas out there as to what `metacognition` really is. Having done my MS thesis in understanding how people learn in engineering programs, I typically think about metacognition as "knowing how to learn." It's typically a goal of engineering education to teach students these skills.

Therefore, I would say it's mostly a cognitive variable, but it's also a behavior because it's a set of habits about how one thinks. How are you planning to measure metacognition? And why inductive reasoning? Why not critical thinking in general?

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Tags: cognitive-psychology, metacognition
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title: Time pressure and learning

text:
# Question
Title: Time pressure and learning
What are the effects of time pressure (salient vs. non-salient) and learning? Salient time pressure is basically when you have a countdown timer in front of you. Non salient time pressure would be when you have a timer going off after some preordained times (making a beep). Would the salient time pressure induce a person to do something more efficiently? Or would it be a distraction?

Sophie Leroy has shown that switching tasks incurs a cost. In particular, there is attentional residue from the previous task. Time pressure, she shows, may help with this. It provides closure to a task. But what are the effects of time pressure on learning? I guess testing is a type of time pressure activity that is one of the best ways to learn.

**References**

W Leroy, S. (2009). Why is it so hard to do my work? The challenge of attention residue when switching between work tasks. Organizational Behavior and Human Decision Processes. Vol. 109. pp 168-181.

# Answer
> 3 votes
This is a wide open question - I'm not sure that you can say there is an "effect on learning" due to time pressure. It's going to depend on a lot of factors, including the learning context, the learner, the amount of time they have to complete the task, etc. Ultimately, all learning is time-limited, so you need to break this down into different lengths of time.

There are several theories that may speak about it. One is cognitive load theory (Paas & Van Merriënboer, 1994). This theory is based on the limitations of working memory, where the "processing" of learning takes place. Basically, there is `intrinsic load` required to learn a certain type of material, and this is a characteristic of the material to be learned. There is also `extraneous load` during learning, which occurs when the learner must divert attention to tasks not directly relevant to the learning task (e.g. checking a clock, computing how much time is left, etc).

Based on CLT, one would expect a decrease in performance from having a clock sitting in front of the learner. But again, I suspect that the amount of time vs. the time required will be a strong mediating factor.

**Edit**

I just skimmed the article you cited. It seems like there are a lot more relevant sources there you could track down. Why don't you do that and come back with what you find?

### References

* Paas, F. G., & Van Merriënboer, J. J. (1994). Instructional control of cognitive load in the training of complex cognitive tasks. Educational Psychology Review,6(4), 351-371

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Tags: learning
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