# Question
Title: What hidden latent variables could be responsible for the high correlation between WORDSUM and IQ?
WORDSUM is a measure of vocabulary ( see sample items here) where the test taker has to select which of a set of words has the most similar meaning to a target word. There's been some discussion of how the test is strongly correlated with IQ.

However, I think that it wouldn't be *that* difficult to lower the correlation between vocabulary and IQ, if you got higher-IQ people to study less vocabulary words, or lower-IQ people to study high vocabulary words. It seems like "an accident of history" (although some "accidents of history" do have high probabilities of happening).

Thus, what hidden latent variables could be responsible for the high correlation between WORDSUM and IQ?

# Answer
> 5 votes
I'd probably reframe your question to be slightly broader, such as "why do vocabulary tests correlate so highly with estimates of general intelligence (i.e., *g*)?".

Anyway, here are a few thoughts:

* Verbal ability measures, including vocabulary tests, are often part of IQ tests. Thus, some of the correlation may flow from our conceptualisation of intelligence as requiring verbal aptitude.
* Ability tests tend to intercorrelate; these correlations are generally greater within a domain (e.g., verbal, spatial, etc.), but even across domains, correlations are observed. Thus, whatever drives correlations between any ability test and general intelligence may also partially explain the vocabulary-IQ correlation. However, this isn't the complete story, because certain tests (from memory, e.g., Raven's Progressive Matrices and Vocab) correlate more with g than others.
* People with greater intelligence may be more likely to seek out verbal stimuli, be provided with verbal stimuli, and retain and understand verbal stimuli, all processes which over many years would accumulate into a greater vocabulary. Similarly perhaps, relatively stable environmental factors might simultaneously increase intelligence and vocabulary.

I'd be keen to read any specific studies which involved a vocabulary based intervention and see whether (a) this was successful in increasing vocabulary test scores, and (b) whether the intervention lowered the correlation with vocabulary and intelligence.

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Tags: intelligence
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title: Does IQ affect learning speed?

text:
# Question
Title: Does IQ affect learning speed?
Supposedly, people of higher levels of intelligence do learn faster than people of lower levels of it. But this is an awfully coarse observation, and different people can learn at drastically different speeds in different environments.

# Answer
A few quick points:

There is a massive empirical literature that shows that fairly strong correlations are obtained between IQ and important real world outcomes, perhaps most notably educational and job performance, often in the r = .5 range (see here for a summary).

Correlations with learning are complicated by what we mean by learning. In particular, if we define learning as the improvement in performance between two time points, then we have what is sometimes called a *difference score* or *gain score*. While this is an intuitive way to think about learning, gain scores often have slightly counter-intuitive properties. For example, on some tasks, gain may be negatively correlated with initial performance levels. This makes sense when you think that those who perform poorly initially often have more to learn. However, initial performance typically correlates well with final performance after a period of learning. As such, correlations of gain scores with ability can be a little strange also.

You might want to read some of Philip Ackerman's work on ability-performance correlations over practice.

There's some further discussion of the change score issue in learning here:

Ackerman, P. L. (1987). Individual differences in skill learning: An integration of psychometric and information processing perspectives. Psychological Bulletin, 102:3-27.
> 13 votes

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Tags: learning, intelligence, iq
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# Question
Title: What are the effects of implanting electrodes into the brains of monkeys?
If one implants electrodes into a monkey's brain in order to allow the monkey to control a mechanical arm, then is the monkeys able to move *both* it's natural *and* it's mechanical arms at once?

What happens if, say, the same signal might tell the mechanical arm to move up, and the natural arm to move down?

# Answer
> 8 votes
The interface between the brain and the hand is not like a USB computer port, and we don't unplug the biological arm and plug in a mechanical one instead. We implant electrodes to just a tiny fraction of the neurons in M1 (about a hundred, out of millions), and use their signals to control the mechanical arm.

So the answer is **yes**. The monkeys don't lose any dexterity in their biological arm because of the Brain-machine interface (BMI). Actually, during the BMI experiments, they usually move their biological arms all over the place. There is no reason why, after enough training, they couldn't control the mechanical arm almost completely independently of the biological arm and at the same time, like you control your digits (almost) independently.

# Answer
> 3 votes
This is indeed possible, but I haven't seen it done experimentally for reasons other than feasibility. Namely, since the **exact same signal** controls both arms, the amount of interesting learning to be had is significantly less than if the signal controls only one arm (e.g. tries to learn to pick up a banana with the mech arm whilst his real arm whacks him in the face).

Also, the standard paradigm of having the monkey control a mechanical arm via neuronal impulses is scientifically valuable because it allows for insights into how we come to know our body in order to manipulate objects in our environment. This two arm procedure doesn't seem to test any conceivable hypothesis about the brain and behavior, so its probably closer to animal torture than science.

Now, if you added electrodes into a separate patch of brain to test if the monkey had enough neuroplasticity to adapt its brain towards controling the new arm **and** remain control over both its natural arms, then I can start to see some reasons for trying this out. Still haven't seen anyone write about actually doing this though.

# Answer
> 2 votes
Theoretically at least, **yes**, it is entirely doable.

In the central nervous system including the brain, sensation, decision and reaction form a feedback loop comprising of different types of nerves. Afferent neurons sense an input such as an external stimulus, interneurons are the connectors in the local circuit, while efferent neurons carry motor signals that activate an organ.

You are apparently referring to a **motor signal when you say 'the same signal'**. Assuming such a signal is generated in some way and then transmitted to the organ(s), it is thereafter **a purely mechanical process** where the organ responds with a movement according to the signal.

It does not matter if the **signal is multiplexed** over to more than one organ, or if the organ happens to be **natural or artificial**. All that matters is the design of the artificial organ.

That is as far as the control systems part of it is concerned. However, the overall functioning is a bit more complex -- e.g., generating the intended signal, and multiplexing it to heterogeneous external organs.

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Tags: neuroscience, animal-cognition
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# Question
Title: How is a young child able to learn language so easily?
It's a well known fact that the earlier children are exposed to languages the better, as young children have a better ability to learn new languages than adults.

* Why is this?
* At what age does a human's mind start to lose this ability?
* What causes the change?
* Does this phenomenon have a name?

# Answer
> 21 votes
It's theorized that there is a Critical Period of language development in children below the age of five (roughly, as age ranges always are in Developmental Psychology).

Probably the most significant and readily verifiable finding is that a **critical period exists for the learning of Phonemes**. Research has suggested children readily differentiate phonemes from all human languages at very early ages; less than 5 years old. There is much debate in Linguistics on this matter and many articles covering the discussion .

After this Critical Period most children and adults can only accurately differentiate and produce phonemes present in their native languages and have difficulty producing and differentiating phonemes from other languages. This is why when learning a language late in life learners often struggle with pronunciation.

A classic example of this is the difficulty native Japanese speakers have with English L and R sounds. As L2, late-in-life second language learners they struggle differentiating the actual sounds and thus producing the different sounds.

There are some interesting theories in what can overcome this deficiency in learning "late" (L2) second languages, see Age and Ultimate Attainment in the Pronunciation of Foreign Languages and Teaching Second-Language Phonetics to Adults.

In addition Noam Chomsky has some interesting interviews and publications about language development in children, such as his interview with Lillian R. Putnam.

Note that Chomsky's opinions and theories are controversial, particularly his concept of a "Language Acquisition Device", which is Nativist to an extreme. There is much material on Chomsky's Theories of Language Acquisition but I would take his theories with a grain of salt.

The Critical Period has been found to apply even to children learning sign language. A good overview on this situation is The critical period for language acquisition and the deaf child's language comprehension : a psycholinguistic approach by Rachel I. Mayberry.

> The critical period hypothesis for language acquisition (CP) proposes that the outcome of language acquisition is not uniform over the lifespan but rather is best during early childhood. The CP hypothesis was originally proposed for spoken language but recent research has shown that it applies equally to sign language

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Tags: cognitive-psychology, developmental-psychology, language
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# Question
Title: Is there a practical limit to the amount of knowledge a human can learn?
There's definitely progressive interference and retroactive interference, which are basically two ways that old memories and new memories can interfere with each other.

But on the other hand, do these types of interference *always* have to happen?

# Answer
> 14 votes
Taken from a purely practical viewpoint, there is a finite number of neurons in the brain, with a finite (though large) number of connections between them. As such, a brain can only contain a finite amount of information. The more that one attempts to learn, the more that the connections between neurons will get obscured as a single memory or idea becomes mapped to a multitude of different related pieces of information or memories.

Evolutionarily, the brain attempts to condense related information to allow for the processing of new and possibly more important data. If you tried to learn everything about every single chair in existence, your memories of different chairs would blur together as your brain tries to force similar things to be considered one memory, especially concerning things that are neither life-threatening or of obvious physical gain. This conclusion is drawn from various theories in Evolutionary Psychology, principally "The cognitive system operates at all times to optimize the adaptation of the behavior of the organism" (John R. Anderson 1990 p. 28). A short summary of these theories can be found here starting on page 783

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Tags: learning, memory
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# Question
Title: What is a neurobiological explanation of borderline personality disorder?
In other words, how do the brains of those with BPD differ from those who don't have BPD?

The Wikipedia article doesn't even contain any possible explanations whatsoever.

# Answer
> 12 votes
The Neurobiology and Genetics of Borderline Personality Disorder indicates that a good deal of research has been done but a specific mechanism causing it has not been pinned down. It appears to be largely genetic which would strongly suggest a neurobiological/nature basis as opposed to a "nurture" related cause. (emphasis mine)

> In summary, the neurobiological research that has been the most useful in shedding light on the physiology underlying borderline personality disorder has examined this multifaceted disorder by examining simpler dimensions of behavior separately, including impulsive aggression and affective instability. **Evidence suggests that impulsive aggression involves a deficit in serotonergic activity**. However, the specific mechanism underlying this remains unknown. It is clear that this component of behavior is substantially genetically encoded, and so new research has focused on elucidating the specific receptors underlying impulsive aggression through the examination of genes coding for specific receptors.

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Tags: neuroscience, abnormal-psychology
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# Question
Title: What is a "delayed match-to-sample task"?
This question talked about how a "delayed match-to-sample task" can be used to measure an animal's working memory. What is a delayed match-to-sample task and how can it be used to measure working memory?

# Answer
> 7 votes
This kind of task is generally used when studying short-term memory. Typically, a subject is presented with some stimuli, followed by a probe item after a varying delay; subjects is then asked to recall (information retrieval) if the probe item was presented before (information encoding). A famous example is Sternberg experiment.

Such tasks can rely on non-verbal material, which makes them good candidates for behavioral studies with animals, but see

> Paule MG, Bushnell PJ, Maurissen JP, Wenger GR, Buccafusco JJ, Chelonis JJ, Elliott R. Symposium overview: the use of delayed matching-to-sample procedures in studies of short-term memory in animals and humans. Neurotoxicol Teratol. 1998 Sep-Oct;20(5):493-502.

Some on-line demonstration can be found on the CANTAB testing battery: Delayed Matching to Sample (DMS).

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Tags: memory, terminology, methodology
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# Question
Title: Is Behaviorism incompatible with Cognitive Psychology?
Both disciplines have historically been at each other's throats, and Radical Behaviorists like B.F. Skinner often completely reject cognitive psychology at a philosophical level.

It seems that today Behaviorism has largely fallen by the wayside but certain principles like Operant Conditioning remain entirely valid.

Are these two philosophies/schools of thought incompatible or part of a greater whole? Is Behaviorism still relevant?

# Answer
> 13 votes
I think cognitive scientists would say that these views are compatible, insofar as cogsci admits results from behaviorism as valid results to be explained by understanding the cognitive constructs underlying them. Obviously (they would say) we have minds, our minds arise from physical processes in our brains, and as such have internal states that sometimes explicitly manifest in behavior, but other times do not manifest in any way that is perceivable. This is not a problem for non-behaviorist cognitive scientists.

Hardcore behaviorists, however, cannot be so accommodating. Internal and non-manifest mental states are *not* admissible in their theoretical universe, and so what most cognitive scientists would have no difficulty in describing as a state change in some internal mental edifice, behaviorists must reframe as some kind of 'mental behavior' in the same way they tried to do with 'verbal behavior.'

Of course, if one is very rigorous, and pushes very hard on this behaviorist view, it is either rendered nonsensical, or becomes an excessively ornate re-statement of normative cognitive science in behaviorist language. What this accomplishes I have no idea, although, to be honest, this seems to be nearly a straw man at this point. Hardcore behaviorists are increasingly hard to spot in the wild.

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Tags: cognitive-psychology, behaviorism
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# Question
Title: Why are some people unable to easily memorize the lyrics to a song?
Although I have listened some songs hundred of times I can't sing the lyrics to any of these songs from beginning to end without pauses. However I am able to whistle the whole song without difficulty.

It seems other people are complaining about this annoying condition as well. This particular answer claims it is quite likely related to the interhemispheric communication:

> I also find that when I take the supplement **piracetam**, my ability improves. (It has in fact improved over time anyway)
>
> Piracetam has something to do with interhemispheric communication.

Any answers for what causes this condition?

# Answer
> 15 votes
### From an information processing perspective, I'd conjecture the following points:

* Many songs have lyrics that are difficult to decipher. If you can't **decipher the words**, then you wont be able to recall them. If you decipher alternate words, then this may reduce the degree to which the words have semantic meaning, and therefore the ease with which the lyrics can be retained and recalled.
* Even when the words of the lyrics are readily discernible, lyrics vary in the degree to which (a) they have easily **discernible meaning**; (b) follow standard grammatical structures; (c) repeat lyrics, etc. Recalling meaningful sentences that follow standard grammatical structure is much easier than recalling random words, and increasing the depth of processing (i.e., greater meaning) of the material should also help with recall (see this discussion of level of processing effect). There would probably also be a range of other effects related to properties of the lyrics which would make a given song easier or harder to recall (e.g., rhyming and rhythm in lyrics might make lyrics easier to discern).
* Practice is a fundamental effect in recall. Thus, the more **times a person has heard a song**, the better they should be at recalling. However, I think this should be qualified with the above points. If a person has heard a song 100 times without actually being able to decipher some of the words or understand their meaning, then that practice may be largely wasted.
* Practice also applies to **recall**, and this would be closely related to **context** effects. Thus, if practice always occurs within the context of the music being played with singer present to assist with any forgotten lyrics, then the person has never practiced in the absence of such cues and may be dependent on the cues. Practicing trying to recall the song without the song in the background, and then with feedback on failed sections would presumably be more effective than just singing along.
* All the above also relates to the distinction in the expertise literature between **deliberate practice and play** (see, Ericsson, Krampe, & Tesch-Romer, 1993, PDF). When people listen to songs, the aim is typically to have a good time rather than to learn the lyrics. Deliberate practice in contrast would involve a deliberate effortful practice regime aimed at learning the lyrics. For example, it might involve a detailed study of the semantic meaning of the lyrics, then repeated recall of the lyrics without assistance, and then correcting on failed sections (e.g., think of an expert pianist learning a piano piece and working on difficult sections, etc.).

### Individual differences

* You ask the question of why some people appear to be better than others at recalling lyrics. It's an empirical question as to whether there is a domain general difference. Presumably, it would reflect a combination of the above effects: e.g., different levels of practice; different levels of understanding of the song lyrics, and perhaps also some more general ability related to verbal recall.

### Recalling melody versus lyrics

* You also ask about why you can recall the melody but not the lyrics. hearing a melody does not require you to understand the lyrics, even if understanding the lyrics might act as useful cue. Thus, in the context where a person does not completely understand the lyrics, he or she may have years of practice hearing the melody, but almost no practice with a semantically meaningful understanding of the lyrics.
* There would also presumably be a wide range of variables in the person that would make them better at recalling a melody (in particular, pitch perception, singing, and musical ability come to mind as factors that should simplify the task of learning a melody).
* Then one could also look at characteristics of the melody which made it harder or easier to recall (e.g., degree of repetition, simplicity of intervals, familiarity of the intervals and structure, etc.).

# Answer
> 10 votes
It likely depends on the cue presented; the study Memory and metamemory for songs: the relative effectiveness of titles, lyrics, and melodies as cues for each other found these interesting results for what portion of Melodies, Titles and Lyrics were correctly remembered vs cues that presented part of the melody or lyrics or the title of the song.

Some related information is on the blog Cognitive Daily in the posts How Do We Remember Songs and Words or music—what do we remember better?

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# Question
Title: Beyond a certain level, is reading comprehension affected more by psychological intuition than by verbal intelligence?
Certainly, you have reading comprehension passages on the SAT, GRE, and LSAT. **But beyond that point, is it really possible to measure reading comprehension through multiple-choice tests?** There are multiple motivations for why an author may make argument X, and multiple interpretations of his exact argument, which may be affected by the immediate circumstances that made him write that argument at that particular point in time (and while we may know a bit about the society that he lived in, chances are that we'll probably never know who he intended the book to be written for - hell - some people probably intended to write a book to impress some potential lover \[and hell, maybe some passages in the book are motivated to attract the sympathy of that lover\] even though they pretended to write it for the greater good of society).

I mean, all you have to do is to look at courtrooms. There, people pretty much argue about what people (in a case with precedent) actually meant, and there's usually no concrete (and correct) answer. And people who study the life of a particular philosopher may have multiple interpretations of why philosopher X wrote passage Y, and what X really meant in writing passage Y.

Plus, it's oftentimes very interesting to read the writing of someone you know REALLY well because you know their life so well that you can dream up hypotheses of what prompted them to write passage X at time Y (and you also know his social network so you could imagine what audience he had in mind, and what audience he might have secretly hoped to impress without mentioning it). And perhaps because of this, reading comprehension is not a skill with a single scale, since people are better at understanding some people than they are at understanding others.

I mean, I guess the ultimate test of reading comprehension would be to test someone on one of Immanuel Kant's books, or on some recent postmodernist book (made artificially difficult to read/parse), and then ask him "well, what is Kant trying to get at"? But is that really a valid test? Or maybe one where you have to dissect the entire structure of a book where X is pretending to be Y pretending to be Y pretending to be X (of course, such books are rarely written, but theoretically possible).

**Alternatively, wouldn't someone with exceptional reading comprehension be better at reading crappy writing?** (because they're probably more able to process multiple thought-streams at once - which includes possible fragmentary/jumbled ideas?) A common assumption in reading comprehension tests is that the writing is "perfect", but this is frequently not the case, and people (especially older people) can get attention lapses when writing

# Answer
The assessment of reading comprehension is not my main area of interest, but some of the many articles on the topic of assessment of reading comprehension may be reflevant. See "measurement of reading comprehension" on Google Scholar (e.g., a couple of the pdfs of reviews here, and here).

This entry in the literacy encyclopedia on assessment of reading comprehension might be a good starting place. The article has a the following quote of a definition of reading comprehension:

> The National Assessment of Educational Progress (NAEP) 2009 Reading Framework Committee defines reading comprehension as ...“an active and complex process that involves understanding written text, developing and interpreting meaning, and using meaning as appropriate to type of text, purpose and situation (National Center for Educational Statistics, 2005, p. 2).

### Here are a few general points:

* Multiple choice testing has the benefit of being reliable given a sufficient number of items. Of course, questions could be raised over the breadth of what it measures (i.e., validity issues).
* Familiarity with the content should increase reading comprehension. Thus, to build on your question, a philosophy student should comprehend more Kant, than a non-philosophy student holding general reading ability constant. A similar argument could be made where the reader has insider knowledge about what the author is trying to say.
* Some texts are more difficult to comprehend in general, whether it be because the text is poorly written (e.g., grammar, spelling, stylistic issues) or because of the complexity of the material.

### Implication of the Rasch model to questions of measurement:

A basic model of responding to multiple choice questions based on Item Response Theory (IRT) is the Rasch model. It basically says that the probability of an individual getting an item correct is a function of their ability and item difficulty.

So according to this model, increasing the difficulty of the reading comprehension items would affect all individuals roughly equally. As can be shown with IRT the reliability of measurement can be increased by setting the difficulty of items to a level that discriminates between individuals. I.e., if items are too difficult, everyone gets the item wrong, and we don't learn much; likewise, if the item is too easy, everyone gets the item right, and we don't learn much. Relating this to your question, including poorly worded writing or really difficult subject matters would only increase difficulty, which would not directly affect measurement of individual differences.

However, the Rasch model is generally simplification of the real world. In general, I think it takes you a long way in understanding the factors driving test performance. However, in some cases you might have reading items which some individuals understand better than others and this factor is unrelated to ability (e.g., a reading that embodies cultural assumptions shared by only some individuals). It is for this reason that reading comprehension tests should probably avoid content where a subgroup is likely to possess substantially more domain specific knowledge on the topic.
> 5 votes

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Tags: cognitive-psychology, intelligence, measurement, reading
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# Question
Title: What type of learning mechanism produces a consistent typo?
There is a typographical error that I make and do so every time I try to type a certain word. Whenever I try to type *remember*, I type *remeber*. I do this every time. This is different to a regular typo because most typos happen at random, whereas this mistake is guaranteed to occur. It's not a spelling mistake, because I know how to spell remember, I just don't press all the required keys.

Could it be related to touch-typing? I don't make the typo when I peck out the keys.

I wonder whether it is related to muscle memory, because there are many words with the pattern 'e\_e', such as *here*, *there*, *gene*, *theme*, *scene*, etc. So where I reach the second *e* my motor system is primed *not* to push the key that came before, i.e. *m*.

It seems that knowledge of spelling and knowledge of typing are not strongly linked in this case.

Is there a mechanism by which I have learnt this mistake?

# Answer
> 6 votes
There is a scientific literature on typing. It's been a while since I've read the articles. You might start by reading this excellent review of research and findings on transcription typing.

### General model of typing

Salthouse (1986) presents a model of the typing process

> ```
> 1. INPUT: Convert text into chunks
> 2. PARSING: Decompose chunks into ordinal strings of characters
> 3. TRANSLATION: Convert characters into movement specifications
> 4. EXECUTION: Implement movement in balistic fashion
>
> ```

A few other relevant points that Salthouse supports with multiple references:

* "The rate of typing is nearly the same for random words as it is for meaningful text."
* "Successive keystrokes from fingers on alternate hands are faster than successive keystrokes from fingers on the same hand."
* "Letter pairs that occur more frequently in normal language are typed faster than less frequent pairs."
* Interkey interval varies with the context of the letters in a word.

These points basically state that typing involves various forms of motor chunking, that the word is a central chunk but that there are also many other lower level chunks (e.g., typing "ion" and "ier" is quite common in English).

### Errors

There's also a discussion of typing errors in the paper.

* Salthouse mentions the taxonomy of typing errors proposed by Wells (1916) of "substitutions, intrusions, ommissions, and transpositions", and also cites empirical estimates of prevalence of different types of errors.
* "Many substitution errors involve adjacent keys."
* "Most transposition errors are cross-hand rather than within-hand"

I suggest you have a read of the paper to get a deeper understanding of the types and proposed causes of typing errors.

### Specific thoughts regarding your question

* Perhaps in contrast to what you say, typos are not random. Rather, there is structure to the errors. For example, "Teh" is a common typo.
* Obviously, having an incorrect belief about the spelling of a word could result in repeated errors, but I understand you are not talking about them.
* So, with regards to a specific word that you frequently mistype, you might want to think whether there are characteristics of the word that make it difficult to type. Also, as you say, if you learn the wrong chunking at some point, you may need to unlearn this pattern.

### References:

* Wells, F. L. (1916). On the psychomotor mechanisms of typewriting. The American Journal of Psychology, 27(1), 47-70.

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Tags: communication, motor, procedural-memory
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# Question
Title: Do people feel emotions less strongly as they grow older?
I'm specifically interested in whether or not their *maximum* ability to feel an emotion decreases as they grow older (so by that I'm meaning - let's ignore the effects of tolerance induced by life experience for now).

# Answer
> 8 votes
### Deconstructing your question

* There is a difference between the ability to experience an emotion and tendency to experience an emotion.
* There is a difference between proportion of time that an individual experiences an emotion and the intensity of that emotion.
* Obviously, you could take many approaches to answering this question. Emotions can be viewed from various perspectives including physiological, psychological, and behavioural.

### Some empirical evidence

I did a quick search on Google Scholar for 'panas longitudinal study'

PANAS (see Crawford and Henry 2004, PDF for a a review) is a commonly used self-report questionnaire that aims to measure the frequency with which various positive and negative emotions have been experienced over a given time frame.

I found this interesting article byKunzmann, Little, and Smith 2000, PDF called "Is age-related stability of subjective well-being a paradox? Cross-sectional and longitudinal evidence from the Berlin Aging Study".

The opening section of the article reviews the empirical literature regarding stability and age related trends in self-reported positive and negative affect. The following are a few interesting points from the article:

* Costa et al. 1987 found correlations over 10 years for positive and negative affect of r =.42 and r=.43 respectively. I.e., there is fair amount of stability in individual differences in the experience of emotions.
* When Kunzmann et al's review of the literature they cite several large scale studies that showed at the group-level no age effect on negative affect, although a couple of studies suggested their might be a small decline in negative affect with age. These studies varied in the years of life that were of interest, but typically looked at differences between early, middle and older adulthood.
* Kunzmann et al also review the evidence for positive affect. The story sounds a little complicated with some studies suggesting a decline in positive affect and others not.
* As I've seen before, it seems like cross sectional studies sometimes show bigger effects than longitudinal studies.

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Tags: neuroscience, aging, emotion
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# Question
Title: Does caffeine improve performance for habituated consumers?
I've seen a fair few studies over the while that suggest caffeine increases arousal in the short term and that for some tasks, this will also increase performance (there's a few citations here).

However, as with most drugs, habituation leads to withdrawal effects and adjustment, so that in some senses once a person gets used to caffeine, having a regular dose of caffeine may just bring a person to something like a normal level of functioning.

Thus, in a general sense, **for someone used to consuming a certain level of caffeine, does having that regular quantity increase arousal or performance over and above the level that would be obtained at that moment had the person never got in the habit of consuming caffeine in the first place?**

# Answer
> 33 votes
### Nehligh's 2010 review

Nehlig (2010) wrote a systematic review article called "Is caffeine a cognitive enhancer?" (link to publisher, no PDF). On page S89 to S90 Nehlig reviews the evidence of caffeine as a cognitive enhancer within the context of a history of caffeine consumption:

> In caffeine non-deprived young (20–25 years) and older subjects (50–65 years), 250 mg caffeine slightly offset the decline in performance found in the placebo group on a digit span memory test. However, caffeine did not improve performance in the immediate word recall task in either age group \[11\]. Caffeine (12.5–100 mg) given after overnight abstinence improved cognitive performance in a relatively difficult and stressful task involving rapid visual information processing and using a high load of working memory in 11 males and 12 females, aged 18–56 years. The effect was more marked in individuals with a high habitual caffeine intake \[78\]. In 68 volunteers consuming a regular daily amount of caffeine, 2 mg/kg caffeine improved the speed of encoding new information in a categorical search task \[79\]. Likewise, in a study comparing 24 non-consumers (20 mg/day) to 24 consumers of caffeine (217 mg/day), there was no baseline difference between group performances. Caffeine improved numeric working memory reaction time and sentence verification accuracy; alertness was also increased, but in general caffeine tended to improve more the performance in non consumers \[80\].
>
> In adult subjects, a higher habitual caffeine intake with no additional caffeine administration on the day of testing was positively related to better performance on incidental verbal learning and visuospatial learning tasks \[15\]. There was also an association between estimated caffeine intake and performance in a choice reaction time task, and in delayed recall of a verbal word learning task \[81\]. In the former study, older sub- jects appeared to benefit more from higher caffeine intake \[15\], while this was not the case in the latter study \[81\]. Also, in real life activities, regular caffeine consumption might benefit cognitive functioning in a non-working population \[82\].

### Smith's 2002 review

Another good review is provided by Smith (2002, PDF). The main claim relevant to the present question argues that coffee remains beneficial despite habituation:

> It has been claimed that the positive eﬀects of caﬀeine really reﬂect removal of negative eﬀects of caﬀeine withdrawal. This view cannot account for eﬀects observed in non-consumers or nondeprived individuals. In addition, there is little evidence of caﬀeine withdrawal impairing tasks which show improvements following ingestion of caﬀeine.

The article is worth reading if you want to read about the relevant empirical evidence and some of the limitations of existing research.

### References:

* \[11\] Rees K, Allen D, Lader M (1999) The influences of age and caffeine on psychomotor and cognitive function. Psychophar- macology (Berl) 145, 181-188.
* \[78\] Smit HJ, Rogers PJ (2000) Effects of low doses of caffeine on cognitive performance, mood and thirst in low and higher caffeine consumers. Psychopharmacology (Berl) 152, 167- 173.
* \[80\] Haskell CF, Kennedy DO, Wesnes KA, Scholey AB (2005) Cognitive and mood improvements of caffeine in habitual con- sumers and habitual non-consumers of caffeine. Psychophar- macology (Berl) 179, 813-825.
* \[81\] Hameleers PA, Van Boxtel MP, Hogervorst E, Riedel WJ, Houx PJ, Buntinx F, Jolles J (2000) Habitual caffeine con- sumption and its relation to memory, attention, planning capacity and psychomotor performance across multiple age groups. Hum Psychopharmacol 15, 573-581.
* \[82\] Smith AP (2009) Caffeine, cognitive failures and health in a non-working community sample. Hum Psychopharmacol 24, 29-34.
* Smith, A. (2002). Effects of caffeine on human behavior. Food and chemical toxicology, 40, 1243-1255. PDF

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Tags: psychopharmacology, arousal, habituation
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# Question
Title: Is the decline of fluid IQ with age less severe for professors and scientists than it is for other people?
This article in Time magazine suggests that engaging in challenging mental tasks may be associated with lower rates of mental decline in older adults. The article states that:

> In one study, presented last year at the Cognitive Neuroscientist Society's annual meeting, psychologist and neuroscientist Helena Westerberg of the Karolinska Institute in Stockholm compared the cognitive abilities of 45 young adults (average age 25) with those of 55 older adults (average age 65). She found that after five weeks of computerized training on tasks ranging from reproducing a series of light flashes to repeating digits in the opposite order that they were given, the older group was able to reach the same level of working memory, attention and reaction time that the younger group had at the outset. (Notably, the younger group had even greater improvements by the end of the training period.) "The program is always pushing them to do better," says Westerberg, who notes that an advantage of video-game training is that the programs' difficulty level continually adjusts upward to match players' evolving abilities. "They have feedback and can see their scores."

This might suggest that scientists and professors might have less decline in fluid IQ with age. Is there any support for this idea?

# Answer
> 10 votes
### Seattle Longitudinal Study:

You might want to have a read about The Seattle Longitudinal Study of Adult Intelligence. There's a summary of the study on this website. To quote the website:

> The Seattle Longitudinal Study of Adult Intelligence has followed a group of more than 5000 people for well over four decades. The program began in 1956 and participants have been tested across a whole gamut of mental and physical abilities at seven year intervals since that date.

With regards to preventing cognitive decline the website suggests that

> The following variables may reduce the risk of cognitive decline in old age:
>
> * absence of chronic diseases
> * a complex and intellectually stimulating environment
> * a flexible personality style at mid-life
> * high intellectual status of spouse
> * maintenance of high levels of perceptual processing speed

If these general points are true, then presumably an argument could be made that scientists and professors have more complex and intellectually stimulating environments. However, the age related declines may be most pronounced in what are potentially post retirement ages (e.g., 60 or 70 +), where the environment would be different.

### Some general points

* Professors and scientists have some of the highest levels of intelligence among the professions (see this table based on this working paper by Hauser, 2002, PDF). Thus, if everyone did decline cognitively at an identical rate, people from such professions would still tend to have higher intelligence (e.g., a 10-point decline from 130 is 120, versus 90 to 80). So, people with initially high intelligence even with decline can still be intelligent. However, this initially high intelligence is most likely due to genetics or some undefined source than to the stimulation of the profession itself.
* Thus, indirectly, the above points (high intelligence of scientists and professors) and potentially environmentally stimulating environments suggest that they will be more intelligent at older age. But my guess is that most of that effect will be due to base line differences in intelligence.

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Tags: intelligence, developmental-psychology, aging
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# Question
Title: Do children show top-down processing as much as adults do?
There has been much research into how top-down processing works, such as the suggestibility of patients to mishear lyrics based on what the patients are told they are.

Is there any research to show that this behavior is evident at a young age, specifically less than about 10 years old?

# Answer
Much evidence suggests **children do not show as much top down processing as adults**. This depends on your definition so I'll state that I generally mean that use of top-down processing appears to increase as a child develops.

Here is the abstract explaining the results of the study Developmental increase in top-down and bottom-up processing in a phonological task: an effective connectivity, fMRI study.

Emphasis mine:

> In older children, top-down control process may selectively enhance the sensitivity of the LTC to bottom-up information from the FG. This may be evident especially in situations that require selective enhancement of task-relevant versus task-irrelevant information. Altogether these results provide a direct evidence for a **developmental increase in top-down control processes in language processing**.

Why is this the case? Generally speaking children need to develop a greater understanding of the world around them before they can put Top-Down and Bottom-Up processing to good use. Piaget framed this in terms of Schemas.

Piaget's Stages of Development (which are contraversial mind you) suggest strongly that children start *almost* at a clean slate and build up schemas as they develop and learn. A younger child simply hasn't had the time to build up schemas for every situation, thus they won't always have a relevant schema to process information in a proper top-down fashion.

Note that other studies suggest that older children have an advantage in some tasks because they learn when to *not* apply top down processing. Younger children may simply not "know" the relevance of each processing method as well.

As stated in Visual search in children and adults: Top-down and bottom-up mechanisms:

> The authors argued that with increasing age, children became able to consider multiple dimensions when making relevant comparisons. One interpretation of these data is that the older (but not the younger) children were able to switch off the top-down system to allow salience to emerge via bottom-up processing.
> 6 votes

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Tags: cognitive-psychology, developmental-psychology
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# Question
Title: What is the difference between solving a problem and acquiring a skill?
Within the confines of cognitive psychology, what is the difference between these two tasks? In the literature, playing chess is generally seen as the exemplar of problem solving. But recently (thanks to this site), I've stumbled upon quite a few articles expounding the merit of using video game playing to study complex *skill acquisition*. This difference in terminology (i.e. chess is a problem to be solved whilst playing a video game like pacman is a skill to be acquired) has me completely confused as to when completing a task is considered a skill acquired/mastered vs. a problem solved.

# Answer
> 9 votes
To take your concrete examples, there are several broad distinctions relevant to comparing a task like chess and a task like playing Pac Man.

### Cognitive versus psychomotor skill

* Research on learning and task performance is divided into various domains of tasks. Two such domains are cognitive, of which chess would be an example, and psychomotor, of which Pac Man would be an example. Video games vary in the relative importance of cognitive versus psychomotor skill.
* You might want to read the Annual Review of Psychology article by Rosenbaum, and Carlson, and Gilmore, 2001, PDF "Acquisition of intellectual and perceptual-motor skills". The article provides an overview of the similarities and differences between cognitive and psychomotor skill acquisition.
* Traditionally, the word "skill" has had psychomotor connotations. But ultimately the defining feature of a skill is that it is acquired through practice, and this applies well to cognitive as it does to psychomotor tasks.

### Learning versus performance

* Some research focuses on how learning occurs, whether it be studying the relationship between practice and performance, examining changes in the errors made over time, and so forth (e.g., see this review by Heathcote et al PDF, called "The power law repealed: The case for an exponential law of practice" which is on the mathematical functional form of the learning curve).
* Other research focuses on performance itself. What are the cognitive processes that underlie performance? In such studies, learning is often a nuisance factor.
* Thus, in the case of both Chess or Pac Man you could focus on either the process of learning or on performance itself (whether it be of a novice or expert).

### Task complexity and time frames of learning

* Research in skill acquisition can broadly be distinguished in terms of the typical time frame it takes to acquire the skill of interest.
* Typical skill acquisition research that is done in the lab involves tasks where meaningful learning can be observed in hours or perhaps days.
* Some other skills can take years to acquire, and this is broadly studied in what is sometimes referred to as the "expertise literature". There have been many studies of chess within the expertise literature. See for example this paper on "the role of deliberate practice in chess expertise" PDF by Charness, Tuffiash, Krampe, Reingold, & Vasyukova, (2005).
* With regards to this distinction, Pac Man presents some difficulty. No doubt one could study meaningful learning in the short term, but also that it might be possible to focus on the learning that might occur for a true Pac Man master who had devoted years to perfecting the art of escaping ghosts and eating little pellets.

# Answer
> 0 votes
This might be a very unscientific answer, but isn't problem solving a type of skill. More specifically, that different kinds of problem solving, are different kinds of skills. I mean that in order to solve chess problems one will utilize the chess-problem-solving-skill?

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Tags: cognitive-psychology, terminology, video-games, learning
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# Question
Title: How does posture affect cerebral blood flow?
This is a follow-up question to an answer on Quora:

> In the upright posture, venous outﬂow is considerably less pulsatile (57%) and occurs predominantly through the vertebral plexus, while in the supine posture venous outﬂow occurs predominantly through the internal jugular veins. A slightly lower tCBF (12%), a considerably smaller CSF volume oscillating between the cranium and the spinal canal (48%), and a much larger ICC (2.8-fold) with a corresponding decrease in the MRI-derived ICP values were measured in the sitting position. \[1\]

I don't quite get the answer though. I know that the cerebral blood flow distribution is more complex than we think, but does the overall blood flow increase or decrease with an upright posture?

# Answer
Blood pressure decreases as one stands up.

A model of cerebral blood flow has been created in Modeling Cerebral Blood Flow Control During Posture Change From Sitting to Standing:

> The characteristic features are that after standing up for 60 s, the pressure (both systolic and diastolic values) drops signiﬁcantly from a mean pressure of approximately 95 mmHg to a mean pressure of approximately 58 mmHg. At the same time, the blood ﬂow velocity also decreases followed by an increase. However, it should be noted that while the mean velocity decreases, the decrease is not as big, because of a large widening of the pulse-amplitude (systolic value minus diastolic value).

Other studies back this claim up such as Cerebral Circulation In Various Physologic States:

> Although our studies have not revealed a quantitative relationship between alterations in the arterial pressure and cerebral blood flow in the same person, there was a definite fall in cerebral blood flow with the fall in effective cerebral arterial pressure on standing.

More specific studies on posture and blood flow have also been performed to learn how to the best way to reduce blood pressure, which is important in head injury patients. From Effect of head elevation on intracranial pressure, cerebral perfusion pressure, and cerebral blood flow in head-injured patients:

> There was no statistically significant change in CPP, CBF, cerebral metabolic rate of oxygen, arteriovenous difference of lactate, or cerebrovascular resistance associated with the change in head position. The data indicate that head elevation to 30° significantly reduced ICP in the majority of the 22 patients without reducing CPP or CBF.

This means that Inter-Cranial Pressure (ICP) was significantly reduced in most patients without reducing Cerebral Blood Flow (CBF). This means changes in pressure *do not* always equate to changes in blood flow of the same relative magnitude.

Reading more into those articles will give you more insight into the complexities of how the flow changes in posture, but unless you have a more specific question I believe that covers what you asked.
> 9 votes

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Tags: neuroscience
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title: How to measure emotional intensity?

text:
# Question
Title: How to measure emotional intensity?
This is a follow-up question to: Do people feel emotions less strongly as they grow older?

Basically - I'm wondering - has anyone ever made an empirical measurement of how strongly someone felt happiness, sadness, anger or grief? Is it also possible to compare intensities of emotion between different people? And if so, how?

# Answer
> 9 votes
Since things like happiness, sadness, and grief are highly subjective, so I don't think there's any way you could measure those variables directly.

You could operationally define those emotions, such as measuring happiness by the number of hours someone spends doing something they enjoy, but you can imagine all of the confounds involved with that.

Or, you could define a general scale (see here for a list of those having to do with pain) and rank how people score on it. Then, you could use principles of non-parametric statistics to compare your rankings.

You could also measure known anatomical correlates (e.g., activity in the amygdala as a basis of fear via fMRI), but so many emotions/feelings/other background processing overlap in certain brain regions that the validity would have to be shown through good controls.

# Answer
> 8 votes
### States versus traits

* In general, it's important to distinguish between emotional states and emotional traits (i.e., the tendency for a person to experience a given emotion, e.g., see trait positive and negative affect scales). Thus, as a side note, there's a lot of research that looks at emotional traits in areas such as personality trait theory and research on subjective well-being (e.g., this chapter by Lucas and Diener, PDF). It sounds like your question is concerned with measuring emotional states.

### General measurement strategies

There are many options for measuring emotional intensity:

* subjective
* behavioural
* physiological / neurological

Both subjective and behavioural measures could be obtained by self-report or other-report.

### Experience sampling

* With regards to measuring the intensity of emotional experience, you may want to read up about experience sampling studies (see the review by Schimmack (2003), PDF). Experience sampling studies use a variety of scales; a common one I've seen involves the use of a grid with hedonic tone on the x-axis (negative to positive) and activation on the y-axis (passive to active). The benefit of experience sampling is that the time between event and measurement is short. Thus, issues related to recall are reduced.
* Of course, one could challenge such a measure on the basis that it is subjective. However, that is an issue of measurement validity. There are many real challenges, but limitations of measurement are not fatal. Evidence can be collected and arguments can be made to justify validity. And even when there are some issues of measurement, meaningful findings can often still be obtained.

### Comparing emotional intensity across individuals

* I agree that there would be issues related to frame of reference effects when it comes to comparing self-reported emotional intensity across individuals. That said I still think that self-report measures would be informative, and that a multifaceted approach combining physiological with other-report and self-report would also be useful.

### References

* Lucas, R. E. & Diener, E. Personality and subjective well-being. FREE PDF
* Schimmack, U. (2003). Affect measurement in experience sampling research. Journal of Happiness Studies, 4, 79-106. FREE PDF

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Tags: measurement, emotion
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# Question
Title: What research gives insight into the terms "low status" and "high status"?
Folk explanations of human behaviour often refer to "high status" or "low status", and the phrase sometimes pops up in more formal contexts (e.g. this question).

However, one of the most cited sources cited as exposition of these concepts is a popular book on improvisational theatre rather than a research publication.

What body of research, if any, addresses these concepts more rigorously?

# Answer
> 2 votes
This is a really broad question - what you seem to be asking is: what research addresses social hierarchies, competition, and neurological/psychological/physiological effects of perception of social status.

It's interesting to note that social status signals likely developed before language, as they are a means of non-verbal communication (language is quite new, evolutionarily-speaking).

In the most broad sense, the answer to your question is that research on social psychology and social neuroscience, particularly that related to hierarchy, dominance, and perception of social standing, is what you're looking for. This is the 'body of research'.

Past this point, I'm not sure what you're asking... Are you wondering in what brain structures this type of behavior appears to originate? Or are you more interested in the cognitive processing going on behind the scenes when people mentally alter their internalized social standing? Or are you looking for a jumping off point?

If you are particularly looking for the neural basis of this behavior, check out the links below. All relate to the neurological basis of social processing in the human brain.

---

Original answer:

I'm at work so I don't have a lot of time to put together a comprehensive answer, but here are some articles:

For the record, the Google search used to find these was `neural correlates of perceived social +status`

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Tags: social-psychology
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# Question
Title: What term describes people that cannot feel pain?
I remember a case study about a girl who could not feel pain due to lacking certain somatosensory receptors; she went on to burn herself on a radiator because she could not feel her flesh burning and suffered many other injuries due to the loss of the sense.

What term describes this deficit?

# Answer
> 13 votes
**Analgesia** is the term used for inability to feel pain. **Hypoalgesia** is the term for low sensitivity to pain.

**Hereditary sensory neuropathy** and **Congenital insensitivity to pain** are two known syndromes that contain these deficits as their symptoms.

# Answer
> 8 votes
I think you may be referring to **congenital analgesia**?

Wikipedia defines this as:

> Congenital insensitivity to pain (CIP), also known as congenital analgesia, is one or more rare conditions where a person cannot feel (and has never felt) physical pain. The conditions described here are separate from the HSAN group of disorders, which have more specific signs and etiology.

The girl you reference is mentioned in *Pain: the science of suffering* By Patrick David Wall:

> One such case was studied over a period of twenty years up to the time she was a student at McGill University in Montreal. A strong pinch to the foot failed to produce a withdrawal or to provoke pain. When pinched and asked what she felt, she replied in a calm way that "it feels like a very strong pressure, and I know that if you pinch much harder you will injure my foot" All her other body sensations-touch, pressure, warm, cold, and movement-appeared completely normal. \[...\] Unusual accidents do occur in such people in novel situations. For example, as a child in the deep Canadian winter, she climbed up to look out of the window and knelt on a hot radiator, one could still see line scars on her knees as an adult.

There's also a very interesting article from HowStuffWorks which refers to this same girl:

> Congenital analgesia is a rare genetic disorder where the individual is unable to feel pain. You might think this sounds like a good thing, but it's actually a life-threatening condition. Pain serves as a warning against injury, so people who don't feel it can be severly injured or hurt by things that most of us would react quickly to. **For example, Ronald Melzack and Patrick Wall describe a girl who got third-degree burns on her knees by climbing on a hot radiator.** There was no signal for her to stop. Researchers are trying to reproduce this condition by genetically altering mice so that they can study the genetic contributions to pain perception.

(Emphasis mine)

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Tags: cognitive-psychology, sensation
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# Question
Title: Are there any connectionist models that integrate reinforcement and  fully supervised learning?
I've been working on modeling some phenomena involving real-time control in an environment with inherent rewards (specifically, playing a 'pong'-like game), and it's increasingly looking like reinforcement learning by itself won't cut it computationally (I'm currently using a temporal difference back propagation neural network).

One possible supplemental learning mechanism is to also have the model predict the environment's future state, from which it can learn from in a supervised manner using standard feed forward back propagation.

My current thinking on synthesizing these mechanisms is to have the input layer feed into a hidden layer, which in turn feeds into **both** a reward predicting layer and a separate state predicting layer. In training this net, I simply change the weights via reinforcement learning first and then change them again to account for the state prediction error via back prop.

**So my question is this**: Are there any problems you can foresee arising from this architecture? Additionally, has this combination of learning mechanisms been done before, and if so was it done in a similar way?

# Answer
> 3 votes
I'm not sure I fully understand your design; perhaps you can clarify what you want your network to learn, why TD-learning "isn't cutting it", and what you mean by 'reinforcement' and 'prediction' learning. In particular, TD-learning *is* a reinforcement learning model, and it *does* reward based on predicted (and not just observed) outcomes. However, you seem to be describing reinforcement and prediction learning as orthogonal models, so again, I'm not sure I understand correctly.

As a general suggestion, you might consider using an Elman/Jordan network (e.g. recurrent neural network/RNN). Rather than relying on knowledge of only the current state to make a prediction about the next state, RNN can learn to recognize sequences of events. This is especially useful for predicting future states in a task that unfolds over time (e.g. \[1\]). I suggest this mostly because you say your task is a 'real-time control' task, but without more knowledge of your task I don't really know if this is appropriate.

As for your suggestion of using two different learning mechanisms to modify a single set of weights-- I don't have the answer, but it seems counterintuitive to me. You're using two different optimization techniques on a single set of data. If the techniques disagree, your network will probably never learn its connection weights. If they agree (i.e., converge on the same answer) then I'm not certain you're adding any value by having two learning mechanisms.

\[1\] Elman (1990). Finding structure in time. Cognitive Science, 14, 179-211. Retrieved from http://synapse.cs.byu.edu/~dan/678/papers/Recurrent/Elman.pdf

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Tags: cognitive-modeling, neural-network, connectionism, artificial-intelligence, reinforcement-learning
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# Question
Title: Summary of meta-analytic correlations between self- and other-report measures
It is well known that the correlation between personality measures obtained from self-ratings and ratings by others are imperfect. There are many different traits that could be rated (e.g., well-being, personality, performance, intelligence, self-esteem, etc.)

Is there a good reference that summarises the correlations between self and other ratings across a wide range of psychological constructs?

# Answer
Some side notes to your question:

* The amount of self-other-agreement depends on the acquaintance of the perceiver with the target (the more acquaintance, the more agreement) and on the "visibility" of the trait (extraversion can be relatively accurately judged by strangers; Neuroticism can only be judged by well-known others; Vazire, 2010)
* Using the Social Relations Model (SRM; Kenny, 1994) more detailed informations about the processes in self- and other ratings can be revealed. For example, one can meaure the amount of assumed similarity (i.e., how much do perceivers generally think that the others are alike to oneself), or the consensus of multiple other-ratings.
* Beyond the pure self-other-correlation it might be interesting to see which rating is more valid in terms of predicting external criteria.

---

References:

Kenny, D. A. (1994). Interpersonal perceptions: A social relations analysis. New York: Guilford Press.

Vazire, S. (2010). Who knows what about a person? The self–other knowledge asymmetry (SOKA) model. Journal of Personality and Social Psychology, 98(2), 281–300. doi:10.1037/a0017908
> 4 votes

# Answer
Here are a few correlations between self-other report.

### Job Performance

* Peer-rated with supervisor-rated job performance
    + r = .62 (Harris and Schaubroeck, 1988)
* Self-rated with supervisor-rated job performance
    + r = .35 (Harris and Schaubroeck, 1988)
* Self-rated with peer-rated job performance
    + r = .36 (Harris and Schaubroeck, 1988)

### Personality

There is a meta-analysis by Connelly and Ones (2010) that summarises Big 5 self-other correlations

It shows a few interesting things:

* Some traits may show greater self-other agreement. This is sometimes attributed to greater observability and lower evaluativeness.
* Closer relationships have stronger correlations.

Here's a study by Costa and MCrae (1988)

* Self-rated with spouse-rated Neuroticism
    + r=.54 and r=.54 (Costa and McCrae, 1988)
* Self-rated with spouse-rated Extraversion
    + r=.60 and r=.53 (Costa and McCrae, 1988)
* Self-rated with spouse-rated Opennness
    + r=.52 and r=.60 (Costa and McCrae, 1988)

### Other resources

* Donaldson, S. I. Grant-Vallone, E. J. (2002, PDF): discussion of self-report bias in organisational research.

### References

* Harris, M. M. & Schaubroeck (1988). A meta-analysis of self-supervisor self-peer, and peer-supervisor ratings. Sample size ranged from 984 to 3,957, and number of correlations averaged ranged from 11 to 36.
* Costa, P. T. & McCrae (1988, PDF). Personality in adulthood: A six-year longitudinal study of self-reports and spouse ratings on the NEO Personality Inventory. It's not a meta analysis. N = 167 for spouse ratings.
* Connelly, B. S., & Ones, D. S. (2010). An other perspective on personality: Meta-analytic integration of observers' accuracy and predictive validity. Psychological bulletin, 136(6), 1092.
> 3 votes

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Tags: measurement, reference-request
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title: Motivation vs Goal Oriented Behavior

text:
# Question
Title: Motivation vs Goal Oriented Behavior
What's the difference between these two terms when used in the context of cognitive psychology? To the best of my knowledge, research on 'Goal Oriented Behavior' refers to the subset of motivation that involves translating explicitly construed goals into actions the agent can perform in order to accomplish these goals (e.g. means-ends analysis). However, its hard for me to grasp when this is *not* the case insofar as theories of motivation are concerned.

So are these terms effectively synonyms with 'Goal Oriented Behavior' simply being the more modern verbiage? Or is 'Goal Oriented Behavior' a special subset of Motivation? Or is the relationship between the two terms something else entirely (perhaps each is used in a different field of study).

# Answer
> 9 votes
Major theories of motivation distinguish between implicit and explicit motives - the first refering to (relatively) unconscious, automatically operating motives, the second refering to motives and goals which are accessible for self-reports (McClelland, Koestner, & Weinberger, 1989). Explicit motives are translated into conscious goals, whereas implicit motives influence spontaneous, uncontrolled, and long-term behavior (without goal-planning behavior).

Furthermore, 'Motivation' referes to a larger process (e.g., selective attention, comparison of set points with actual situations, the processing of situational incentives), where the translation into goals and actions only is the last part of a sequence of processing steps.

Concerning your question, I would say that 'goal oriented behavior' indeed is a subset of motivation, namely explicit motivation.

---

**References**

McClelland, D. C., Koestner, R., & Weinberger, J. (1989). How do self-attributed and implicit motives differ? Psychological Review, 96, 690-702.

Schultheiss, O. C. (2008). Implicit motives. In O. P. John, R. W. Robins, & L. A. Pervin (Eds.), Handbook of personality psychology: Theory and research (3rd ed.). (pp. 603-633). New York, NY US: Guilford Press.

# Answer
> 3 votes
One example, I can think of, which is an example of motivation, which does not need to be driven by wanting to accomplish a goal is doing arts. The motivation to play an instrument might be to learn how to master the instrument, but is might as well come from enjoyment of earning how to master the instrument. In the latter case, it is not so important whether one will ultimately master the instrument, because it is the process of learning it, which is the fun part.

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Tags: cognitive-psychology, terminology, motivation, behavior
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# Question
Title: Is there a term for individuals who can "visualize" numbers and advanced mathematics?
I recently saw an episode of 60 Minutes about Jacob Barnett, a 13 year old boy who is currently attending advanced physics classes at a local university and was portrayed by the show as being a child prodigy/genius. In the interview, he demonstrates how he's able to perform mathematical transformations in his head by visualizing the numbers as colored shapes. As he explains in the linked clip:

> This is `2 * 27`:

He visualizes multiplying 2 by 27 as a series of colored triangles.

Is this a known phenomenon, and if so, does it have a name? Do other individuals visualize mathematics like this? Or is this just a 12-year old kid... embellishing (to be polite) his thought process?

# Answer
Sounds like a form of Synesthesia, in particular it sounds like Number Form Synesthesia mixed with Grapheme-color Synesthesia:

> A number form is a mental map of numbers, which automatically and involuntarily appears whenever someone who experiences number-forms thinks of numbers. Number forms were first documented and named by Francis Galton in "The Visions of Sane Persons". Later research has identified them as a type of synesthesia. In particular, it has been suggested that number-forms are a result of "cross-activation" between regions of the parietal lobe that are involved in numerical cognition and spatial cognition

It doesn't seem exactly like what he does but it could be a form of it. It's hard to imagine just how it would be to perceive the world as a synesthesic person does.

It sounds like he's learned to apply his visual-spatial skills to "arrange" the number forms to aid his calculations.

Synesthesia is covered in detail in the book Synesthesia: a union of the senses, though I'm not aware of any specific case studies on individuals with this exact set of skills.

A term to describe people with Synestesia is **Synesthesic**.
> 21 votes

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Tags: terminology, intelligence, problem-solving, mathematical-ability
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# Question
Title: Is procrastination greater when skill is low and rewards offer low status boost and does this lead to efficient  task allocation in groups?
I am very interested in procrastination, because it is such a clear sign of lack of motivation. I have a hypothesis about why we procrastinate, which I would like to get tested by you.

The assumption for this hypothesis is that we are more likely to procrastinate on tasks, which we are not good at, or which does not yield a sufficiently large boost in status.

If this assumption is correct, then I believe that a group of people, where all members are able to do all tasks, would become more efficient if those group members who were less efficient at solving a task would procrastinate and never get it done, so it could get solved by someone who is better at it. Similarly, it would be good if the whole group procrastinate on tasks, which do not yield a sufficiently large boost in status, because this way the group can allocate more status to tasks that are more important and this way avoid having the members do tasks, which they just felt like doing.

### Questions

* Are individuals more likely to procrastinate on tasks that they are not good at?
* Are individuals more likely to procrastinate on tasks when the rewards in terms of status boost for successfully completing the task are low?
* Does procrastination serve a functional role in efficiently allocating tasks in groups?

# Answer
As a starting point, the Steel (2007) meta-analysis in the highly regarded *Psychological Bulletin* is an excellent starting place for learning about the theoretical and empirical literature on procrastination. However, a lot of the literature seems to be focused on procrastination as trait, rather than treating procrastination as a task specific, temporally varying phenomena (which I think is what is more relevant to your question).

### Defining procrastination

Before we can talk about the causes and consequences, we should define *procrastination*. The wikipedia article on procrastination cites Steel (2007) who defined procrastination as

> "to voluntarily delay an intended course of action despite expecting to be worse off for the delay."

Thus, we should be clear that procrastination is not intentional stalling with the aim of getting out of a task.

### Skill, difficulty, and procrastination

Steel (2007) suggests that procrastination may be greater when:

* people have low self-efficacy, fear of failure, and perfectionism

Self-efficacy may be due to an actual lack of skill or may be a bias in thinking.

From a utility perspective, for a constant level of reward, having lower levels of skill on a task or doing a task that is more difficult, increases the cost of obtaining the reward. I can also see a specialisation argument, whereby people seek out domains that they are good at because the link between effort and reward is shorter.

So in summary, I think there is reasonable theoretical support for the idea that being bad at a task whether through lack of skill or inherent task difficulty may increase procrastination (or even task avoidance).

### Rewards and procrastination

I'd be more comfortable defining your question in terms of rewards rather than specifically focussing on social status. Social status is one, albeit very important, type of reward. However, I think as a starting point, it would be easier to think about the rewards provided by the task. Also, it is probably also worth thinking about the flipside, the punishment (or loss of rewards) that flow from not doing a task.

In reviewing the literature, Steel (2007) suggests that procrastination may be greater when:

* the task is aversive in itself
* rewards are more distal

It is also implied by the concept of procrastination that the person does want to do the task in the longer term, whether this be out of obligation or for another more material reward. That said, greater reward and less distal rewards should reduce procrastination. Also, increasing the punishment and temporal proximity of not completing the task should reduce procrastination (as perhaps many all-nighter before an assignment is due can attest).

More broadly, there is a school of thought typified by this blog post by Daniel Lemire that sees procrastination as sometimes representing an adaptive indicator that one should focus on different tasks.

Thus, in a broad sense, reduced rewards for task completion should both increase procrastination and task avoidance.

### Functional role of procrastination

Thus, in broad terms there is a theoretical argument suggesting that reward structures and the distribution of skill should lead to specialisation whereby people generally will tend towards doing tasks to which the opportunity cost is less than that for others. That said, there is a difference between procrastination and task avoidance in that task avoidance implies someone does not want to do the task at all.

Anyway, while the above analysis touches on the empirical literature, it is largely driven by a theoretical analysis grounded in concepts of rationality and utility maximisation. I'd be interested to read about what specific empirical studies have been conducted to test some of these ideas.

### References:

* Steel, P. (2007). The nature of procrastination: A meta-analytic and theoretical review of quintessential self-regulatory failure. Psychological Bulletin 133 (1): 65–94. FREE PDF
> 8 votes

# Answer
I believe that Dan Ariely's experiment contradicts your assumption, since he shows that avoiding procrastination makes you better in the task. Thus, the correlation between performance and procrastination is in the opposite causality from what you propose.

see: http://bookoutlines.pbworks.com/w/page/14422685/Predictably%20Irrational for details. copy pasted from there:

## The Experiment

* Ariely conducted an experiment on his class. Students were required to write three papers. Ariely asked the first group to commit to dates by which they would turn in each paper. Late papers would be penalized 1% per day. There was no penalty for turning papers in early.
* The prudent response is to commit to turning all three papers in on the last day of class.
* The second group was given no deadlines; all three papers were due in the last day of class.
* The third group was directed to turn their papers in on the 4th, 8th, and 12th weeks.

## The Results?

Group 3 (imposed deadlines) got the best grades. Group 2 (no deadlines) got the worst grades, and Group 1 (self-selected deadlines) finished in the middle. Allowing students to pre-commit to deadlines improved performance Students who spaced out their commitments did well; students who did the logical thing and gave no commitments did badly.

These results suggest that although almost everyone has problems with procrastination, those who recognize and admit their weakness are in a better position to utilize available tools for precommitment and by doing so, help themselves overcome it.
> 6 votes

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Tags: motivation, evolution
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# Question
Title: Has the neuro-linguistic programming visual model been scientifically tested?
According to the NLP visual model, fast flickers of the eyes in left/right and the 4 diagonal directions map to simple cues related to how a person is thinking. Thease are "visual constructed", "visual remembered", "auditory constructed", "auditory remembered", "kinesthetic" and "internal dialogue".

The same directions are generally mapped to the same cues but not always, additionally the left/right is reversed in the left handed. There are other cues such as in the neck that indicate further when combined with cirtain eye cues, not to be confused with observation of muscle twitches when thinking about an associated action that also occurs in NLP. Sequences of these combine to indicate thought processes.

* **Have these propositions about these cues been scientifically tested?**
* **If so, what are the results?**

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

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

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

> Michael Heap (1988) conducted a systematic review of the research literature on NLP and found that it was lacking in evidence.
>
> The present author is satisfied that the assertions of NLP writers concerning the representational systems have been objectively and fairly investigated and found to be lacking. These assertions are stated in unequivocal terms by the originators of NLP and it is clear from their writings that phenomena such as representational systems, predicate preferences and eye-movement patterns are claimed to be potent psychological processes, easily and convincingly demonstrable on training courses by tutors and trainees following simple instructions, and, indeed, in interactions in everyday life. Adding,
>
> Therefore, in view of the absence of any objective evidence provided by the original proponents of the PRS hypothesis, and the failure of subsequent empirical investigations to adequately support it, it may well be appropriate now to conclude that there is not, and never has been, any substance to the conjecture that people represent their world internally in a preferred mode which may be inferred from their choice of predicates and from their eye movements. \[…\] These conclusions, and the failure of investigators to convincingly demonstrate the alleged benefits of predicate matching, seriously question the role of such a procedure in counselling.

### References:

* Heap, M. (1988). Neuro-linguistic programming, In M. Heap (Ed.) Hypnosis: Current Clinical, Experimental and Forensic Practices. London: Croom Helm. FREE PDF
> 10 votes

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Tags: cognitive-psychology, theory-of-mind, eye-movement, neuro-linguistic-prog
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title: Why is recognition easier than recall?

text:
# Question
Title: Why is recognition easier than recall?
The main ways of memory retrieval are recognition and recall.

Why has it been found that recognition is "easier" to perform, meaning it is usually faster or is more likely to yield an accurate retrieval?

# Answer
I'm not familiar with the paper Ofri cites, but will agree with the OP that recognition is generally considered to be an easier task than recollection, and successful recognition considered weaker evidence for any particular memory phenomenon. One common explanation is that recognition can manifest psychologically simply as a result of the increased cognitive fluency brought about by priming -- see for example Alter & Oppenheimer 2009. Priming effects are *extremely* robust -- subjects will show priming on an image they saw once, a year ago, for less than a second. (See Brady et al. 2011 for review.)

If recognition amounts to the psychological state wherein some stimulus is slightly easier to process than another, and this effect can be achieved with essentially no cognitive work, but rather as a manifestation of a kind of mere exposure, then it seems clear why recollection -- which requires a complex dance of inhibition and excitation in order to activate some target thought or memory from amongst a host of competitors (see for example Anderson et al. 2000) -- should be the more difficult of the two processes to accomplish, as, in fact, it generally seem to be.

> Alter, A. L., & Oppenheimer, D. M. (2009). Uniting the tribes of fluency to form a metacognitive nation. Personality and Social Psychology Review, 13(3), 219-235.
>
> Brady, T. F., Konkle, T., & Alvarez, G. A. (2011). A review of visual memory capacity: Beyond individual items and toward structured representations. Journal of Vision, 11(5).
>
> Anderson, M. C., Bjork, E. L., & Bjork, R. A. (2000). Retrieval-induced forgetting: Evidence for a recall-specific mechanism. Psychonomic Bulletin & Review, 7(3), 522-530.
> 11 votes

# Answer
It is not. At least not always: In this famous experiment Tulving and Thomson show that under certain circumstances recall can be better than recognition.

It seems that the reason why recognition is *usually* more accurate than recall, is the context. Usually, the context in the recognition test is very similar to the conditions in the learning phase - the subject sees a list of words. In the free recall test, the context is different - the subject is not given any external stimulus.

Tulving and Thomson changed that in their experiment: the context of learning was more similar to the recall test, which resulted in higher performance in the recall.

This indicates that the encoding in memory has some context specificity. Items that were encoded using a visual stimulus will be easier to recognize or recall if the same or similar stimulus is presented during the test.

*Note:* I interpreted the word 'easier' in the question as 'more accurate' because typically accuracy is measured, and not the 'ease' of the recall/recognition, which could be defined in many different ways.

> Tulving, E., & Thomson, D. M. (1973). Encoding specificity and retrieval processes in episodic memory. Psychological review, 80(5), 352-373. PDF
> 11 votes

# Answer
There is a lot of evidence that our brains work most fundamentally as pattern-matching engines ( simplistic, but sufficient for the purpose ). Which would definately favour recognition, because this involves matching a newly perceived pattern with an already stored one, something that we do well.

Recall, OTOH, involves keyed data access - that is, identifying the links via another piece of information - when you saw something, or a tray that used to have objects on. The cognitive processes are not as good at this because the way the information is retrieved is not based on time or place, which are abstract entities.

So "did the face look like this one" will produce quicker responses than "how big was his nose". This is why photofit and sketches are so important - they trigger recognition. Of course, this form of recognition - of faces - is so strongly wired that it can produce a lot of false positives. But that is identification accuracy, rather than recognition accuracy.
> 5 votes

# Answer
A quick explanation for why recognition may seem easier than recall is due to advantages that come into play for recognition that aren't present for recall. In particular, on a recognition test, subjects are presented with what are called "copy cues" -- in other words, duplicates of studied items. When studied items actually show up on the test, subjects are able to use two types of processing to respond: (1) recollection, which is careful, controlled responding that is based on retrievable episodic and contextual detail (present in both recognition and recall) as well as (2) familiarity, which is quick, heuristic-based deciding (generally more readily available in recognition memory). These processes are not unlike Kahneman and Tversky's famous processing types.

Ofri's answer is a good one, however -- it's very interesting to spot situations where recognition is actually less successful than recall. Recognition failure of recallable words is one such instance.
> 5 votes

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Tags: cognitive-psychology, memory, recognition
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# Question
Title: How much more efficient is interleaving skills when learning?
In an interview with Robert A. Bjork this article suggests interleaving skills is better than focusing exclusively on one skill at a time. How much of a difference does the research indicate that it makes?

# Answer
> 8 votes
I think it would be unfair to reduce this effect to a single number-- most certainly, it depends on the task at hand, as well as a number of other factors.

To give a rough idea, though, you may want to look at Richland et al. (2005) who found roughly a 25% increase in retention on a knowledge test when using interleaving. Also noted in this article,

> Interleaving has been shown to be more effective for producing learning than blocking or massing learning (A1A2A3A4A5B1B2B3B4B5) on many diverse sets of stimuli including word pairs (Battig, 1979), motor patterns (Shea & Morgan, 1979), and word translations (Richland, Bjork & Finley, 2004)

Robert Bjork claims that interleaving is only one intervention among a class of "desirable difficulties", or things that might make your task seem harder but will improve it in the long run. Other such desirable difficulties include generation (e.g., fill in the blank rather than multiple choice; see Karpicke & Roediger (2008)) and the spacing effect (studying at regular spaced intervals is more effective than studying everything all at once). Bjork has shown that interleaving is not just an artifact of the spacing effect--after all, interleaving requires spacing--but that its contribution to retention is in addition to spacing.

If you head on over to Bjork's lab webpage you'll see that he has a decades of research publications available free for download.

Richland, Bjork, Finley, & Linn (2005). Linking Cognitive Science to Education: Generation and Interleaving Effects. FREE PDF

Karpicke, & Roediger (2008). The critical importance of retrieval for learning. Science, 319, 966-968. Retreived from https://www.msu.edu/course/psy/101/altmann/karpickeRoediger08.pdf

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Tags: learning
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# Question
Title: What are the main causes of whether a person becomes introverted or extraverted?
Genetics is obviously an important cause of whether someone becomes extraverted or introverted. But what percentage is genetics and what percentage is the environment? What factors in the environment are most important in determining this trait?

# Answer
> 9 votes
### Heritability estimates of Extraversion (and other Big 5 factors)

The introduction section of Loehlin et al (1998) provides a narrative review of heritability estimates of big 5 personality traits (i.e., one of which is extraversion). A brief extract gives a flavour of some of the research that has been conducted:

> A recent heritability analysis of the Big Five dimensions as measured by the Revised NEO Personality Inventory of Costa and McCrae (1992) used a total of 660 monozygotic (MZ) pairs and 380 dizygotic (DZ) pairs from pooled Canadian and German twin samples (Jang, McCrae, Angleitner, Riemann, & Livesley, 1998). For all five traits a simple model involving only additive genes and nonshared environment fit the data. Estimates for the heritabilities of factor scales for \[Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness\] were .50, .48, .49, .49, and .48, respectively. These estimates are obviously very similar—in partic- ular, the heritability of Agreeableness is quite in line with the rest.

They also mention other twin studies, with heritability estimates for Extraversion, Agreeableness, Conscientiousness, Neuroticism, and Openness respectively as:

```
                       E    A    C    N    O
Waller (1999):        .49  .33  .46  .42  .58
Riemann et al (1997):  60  .57  .71  .61  .81

```

Thus, in summary, it seems that such estimates for the heritability of extraversion are around 50%.

### Side Point

* While inventories like the Myer-Briggs Type Inventory often categorise individuals, into categories, I find a continuous approach to personality traits provides a more accurate description of an individual. Using such an approach, people have a score on an extraversion dimension that is roughly normally distributed (or at least continuously distributed) in the population.

### Limitations

* I realise this only partially answers your question. It doesn't discuss the dynamic environmental-genetic interactions that cause personality traits , nor does it take a critical perspective on issues related to the measurement of extraversion, and the estimation issues related to heritability. Hopefully, it is a useful starting point.

### References

* Jang, K. L., McCrae, R. R., Angleitner, A., Riemann, R., & Livesley, W. J. (1998). Heritability of facet-level traits in a cross-cultural twin sample: Support for a hierarchical model of personality. Journal of Personality and Social Psychology, 74, 1556–1565.
* Loehlin, J.C. and McCrae, R.R. and Costa, P.T. and John, O.P. (1998). Heritabilities of common and measure-specific components of the Big Five personality factors. *Journal of Research in Personality*, 32, 4, 431-453. FREE PDF
* Riemann, R., Angleitner, A, & Strelau, J. (1997). Genetic and environmental influences on personality: A study of twins reared together using the self- and peer report NEO-FFI scales. Journal of Personality, 65, 449–475.
* Waller, N. G. (1999). Evaluating the structure of personality. In C. R. Cloninger (Ed.), Personality and psychopathology (pages 155-197). Washington, D.C.: American Psychiatric Press. FREE PDF

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Tags: developmental-psychology, nature-nurture, genetics, personality
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# Question
Title: Studies modelling learning curves of an overall task and subtasks
### Background

Lee and Anderson (2001) published an article in which they argued that learning a complex skill can be understood in terms of learning various component skills. They did this by performing a hierarchical task analysis on the Kanfer-Ackerman Air Traffic Control Task. They then re-analysed a dataset where participants performed the task over repeated trials. By examining key logs, they were able to extract out the speed with which overall goals were achieved (e.g., landing planes) as well as subtasks (e.g., moving planes through the hold patterns, etc.). They then analysed the relationship between practice and performance (i.e., the learning curve) for both the overall task and the subtasks. Specifically, they fit three parameter power functions.

I'm currently doing some research exploring similarities and differences between overall and subtask learning curves, and I'm keen to identify other papers that have modelled subtask and overall task performance. However, the learning and performance literature is pretty broad and crosses multiple disciplines, and thus, somewhat challenging to search. I've also tried the cited by link for the article on Google Scholar.

### Question:

* What, if any, other studies have been published that have modelled the relationship between both practice and subtask performance, and practice and overall task performance?

My preference is for studies where the dependent variable is task/subtask completion time, but any dependent variable representing performance would be interesting.

### References

* Lee, F. J. and Anderson, J. R. (2001). Does learning a complex task have to be complex?: A study in learning decomposition. Cognitive Psychology, 42(3):267-316. FREE PDF

# Answer
> 4 votes
I've been interested in this issue from another direction, namely, in how to model the acquisition of hierarchically decomposeable behaviors of the type you describe; and how these behaviors, once acquired, can be used as 'high order primitives' to bootstrap other learning. This is an important issue for artificial intelligence and machine learning, in particular, as a way to address the combinatorial explosion involved with learning complex tasks in realistic domains.

Barto et al. (2004) provide a nice overview that amends the standard reinforcement learning paradigm to take these hierarchical ideas into account, and includes an algorithmic implementation for a simple but non-trivial domain. Oudeyer et al. (2007) expand on how hierarchicality can make behavior acquisition more efficient, and implement their algorithm in a robot in a developmental setting. Botvinick et al. (2009) provide a more recent review of the state of this work, as well as an overview of possible neural correlates of some of the processes.

Taken together, these references may possibly be useful to you as dispatches from domains other than the one you're exactly interested in. I've found such disparate formulations to be fertile sources of inspiration and synthesis.

# Answer
> 3 votes
Based on the Anderson cite, I'm assuming you've looked a bit more at the ACT-R literature-- task analysis is a common prerequisite for creating ACT-R models and you'll find lots of tasks modeled as a series of sub-tasks in a goal hierarchy. Offhand, though, I don't know any ACT-R articles that look specifically at your question of interest...

On a different note, Catrambone (1998) may be of interest to you-- in this article, he looks out how breaking down math problems into sub-goals helps students learn the material better. One claim is that breaking a problem down into smaller components helps transfer when a novel problem is made up of some (but not necessarily all) of the components. It eliminates reliance on rote performance, which often requires cues from previous steps in order to transition into subsequent steps.

Catrambone, R. (1998). The subgoal learning model: Creating better examples so that students can solve novel problems. Journal of Experimental Psychology: General, 127, 355-376. FREE PDF

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Tags: performance, learning, task-analysis
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