Monday, December 17, 2007

Baboon Metaphysics: Tabula Rasa and Group IQ


I recently came across this free excerpt from the Baboon Metaphysics: The Evolution of a Social Mind. From the excerpt the book seems very promising.

First, let me tell you how, the book got its name. It got its name from a quote by Darwin, while he was contemplating the debate between empiricists (we gain knowledge from experiences- tabula rasa) and rationalists (we have innate schema, intuition and logic that is independent of experiences) as to how we acquire knowledge, and how evolutionary theory might provide the answers.

With growing excitement, Darwin began to see that his theory might allow him to reconstruct the evolution of the human mind and thereby resolve the great debate between rationalism and empiricism. The modern human mind must acquire information, organize it, and generate behavior in ways that have been shaped by our evolutionary past. Our metaphysics must be the product of evolution. And just as the key to reconstructing the evolution of a whale’s fin or a bird’s beak comes from comparative research on similar traits in closely related species, the key to reconstructing the evolution of the human mind must come from comparative research on the minds of our closest animal relatives. “He who understands baboon would do more towards metaphysics than Locke.”


The authors then go on to confront behaviorist thoughts with experimental results that show that many animals come pre-programed in this world.

Song sparrows (Melospiza melodia) and swamp sparrows (Melospiza georgiana) are two closely related North American birds with very different songs. Males in both species learn their songs as fledglings, by listening to the songs of other males. But this does not mean that the mind of a nestling sparrow is a blank slate, ready to learn virtually anything that is written upon it by experience. In fact, as classic research by Peter Marler and his colleagues has shown, quite the opposite is true. If a nestling male song sparrow and a nestling male swamp sparrow are raised side-by-side in a laboratory where they hear tape-recordings of both species’ songs, each bird will grow up to sing only the song of its own species.

The constraints that channel singing in one direction rather than another cannot be explained by differences in experience, because each bird has heard both songs. Nor can the results be due to differences in singing ability, because both species are perfectly capable of producing each other’s notes. Instead, differences in song learning must be the result of differences in the birds’ brains: something in the brain of a nestling sparrow prompts it to learn its own species’ song rather than another’s. The brains of different species are therefore not alike. And the mind of a nestling sparrow does not come into the world a tabula rasa—it arrives, instead, with genetically determined, inborn biases that actively organize how it perceives the world, giving much greater weight to some stimuli than to others. One can persuade a song sparrow to sing swamp sparrow notes, but only by embedding these notes into a song sparrow’s song. It is almost impossible to persuade a swamp sparrow to sing any notes other than its own. Philosophically speaking, sparrows are Kantian rationalists, actively organizing their behavior on the basis of innate, preexisting schemes.

They then go on to discuss studies by Tolman and his students that gave a blow to behaviorism and introducing knowledge as an intermediary between stimulus and response.

In 1928, Otto L. Tinklepaugh, a graduate student of Tolman’s, began a study of learning in monkeys. His subjects were several macaques who were tested in a room in the psychology department at the University of California at Berkeley (sometimes the tests were held outdoors, on the building’s roof, which the monkeys much preferred). In one of Tinklepaugh’s most famous experiments, a monkey sat in a chair and watched as a piece of food—either lettuce or banana—was hidden under one of two cups that had been placed on the floor, six feet apart and several feet away. The other cup remained empty. Once the food had been placed under the cup, the monkey was removed from the room for several minutes. Upon his return, he was released from the chair and allowed to choose one of the cups. All of Tinklepaugh’s subjects chose the cup hiding the food, though they performed the task with much more enthusiasm when the cup concealed banana.

To illustrate the difference between behaviorist and cognitive theories of learning, pause for a moment to consider the monkey as he waits outside the experimental room after seeing, for example, lettuce placed under the left-hand cup. What has he learned? Most of us would be inclined to say that he has learned that there is lettuce under the left-hand cup. But this was not the behaviorists’ explanation. For behaviorists, the reward was not part of the content of learning. Instead, it served simply to reinforce or strengthen the link between a stimulus (the sight of the cup) and a response (looking under). The monkey, behaviorists would say, has learned nothing about the hidden food—whether it is lettuce or banana. His knowledge has no content. Instead, the monkey has learned only the stimulus-response associations, “When you’re in the room, approach the cup you last looked at” and “When you see the cup, lift it up.” Most biologists and laypeople, by contrast, would adopt a more cognitive interpretation: the monkey has learned that the right-hand cup is empty but there is lettuce under the left-hand cup.

To test between these explanations, Tinklepaugh first conducted trials in which the monkey saw lettuce hidden and found lettuce on his return. Here is his summary of the monkey’s behavior:

Subject rushes to proper cup and picks it up. Seizes lettuce. Rushes away with lettuce in mouth, paying no attention to other cup or to setting. Time, 3–4 seconds.

Tinklepaugh next conducted trials in which the monkey saw banana hidden under the cup. Now, however, Tinklepaugh replaced the banana with lettuce while the monkey was out of the room. His observations:

Subject rushes to proper cup and picks it up. Extends hand toward lettuce. Stops. Looks around on floor. Looks in, under, around cup. Glances at other cup. Looks back at screen. Looks under and around self. Looks and shrieks at any observer present. Walks away, leaving lettuce untouched on floor. Time, 10–33 seconds.

It is impossible to escape the impression that the duped monkey had acquired knowledge, and that as he reached for the cup he had an expectation or belief about what he would find underneath. His shriek reflected his outrage at this egregious betrayal of expectation.

Later they move on to their central premise, that baboons offer a good model to study the evolution of (human) mind.

Moreover, the conservation status of baboons confers neither glamour nor prestige on those who study them. Far from being endangered, baboons are one of Africa’s most successful species. They flourish throughout the continent, occupying every ecological niche except the Sahara and tropical rain forests. They are quick to exploit campsites and farms and are widely regarded as aggressive, destructive, crop-raiding hooligans. Finally, baboons are not particularly good-looking—many other monkeys are far more photogenic. Indeed, through the ages baboons have evoked as much (if not more) repulsion than admiration.

Baboons are interesting, however, from a social perspective. Their groups number up to 100 individuals and are therefore considerably larger than most chimpanzee communities. Each animal maintains a complex network of social relationships with relatives and nonrelatives—relationships that are simultaneously cooperative and competitive. Navigating through this network would seem to require sophisticated social knowledge and skills. Moreover, the challenges that baboons confront are not just social but also ecological. Food must be found and defended, predators evaded and sometimes attacked. Studies of baboons in the wild, therefore, allow us to examine how an individual’s behavior affects her survival and reproduction. They also allow us to study social cognition in the absence of human training, in the social and ecological contexts in which it evolved.

This same theme, of baboons having a greater social/group IQ is also touched upon by fellow ScientificBlogger Howard Bloom in a series of fascinating articles at the Scientificblogging.com, where I also blog. specifically Bloom refers to baboons and how they are smarter than chimpanzees, by being able to adapt to any environment (a more plausible definition of intelligence, instead of the usual anthropomorphic one we are accustomed to).

The ultimate test of intelligence is adaptability—how swiftly you can solve a complex problem, whether that problem is couched in words, in images, in crises, or in everyday life. The arena where intelligence is most important is not the testing room, it’s the real world. When you measure adaptability by the ability to turn disasters into opportunities and wastelands into paradises, bacteria score astonishingly high. But how do big-brained chimpanzees and small-brained baboons do? Or, to put it differently, how adaptable, clever, mentally agile, and able to solve real-world problems have chimpanzees and baboons proven to be?

He illustrates the above with a real world field study case example that showed the high adaptability of baboons.

Baboons have been called “the rats of Africa.” No matter how badly you desecrate their environment, they find a way to take advantage of your outrage. One group, the Pumphouse Gang, was under study for years by primatologist Shirley Strum. When Strum began her baboon-watching, the Pumphouse Gang lived off the land in Kenya and ate a healthy, all-natural diet. They ate blossoms and fruits when those were in season. When there were no sweets and flowery treats, the baboons dug up roots and bulbs.

Then came disaster—the meddling of man. Farmers took over parts of the baboons’ territory, plowed it, built houses, and put up electrified fences around their crops. Worse, the Kenyan military erected a base, put up homes for the officers’ wives and kids, and trashed even more of the baboons’ territory by setting aside former baboon-land for a giant garbage heap. If this had happened to a patch of forest inhabited by chimps, the chimpanzee tribes would have been devastated. But not the baboons.

At first, the Pumphouse Gang maintained its old lifestyle and continued grubbing in the earth for its food. Then came a new generation of adolescents. Each generation of adolescent baboons produces a few curious, unconventional rebels. Normally a baboon trip splits up In small groups and goes off early in the day to find food. But one of the adolescent non-conformists of the Pump House Gang insisted on wandering by himself. His roaming took him to the military garbage dump. The baboon grasped a principle that chimps don’t seem to get. One man’s garbage is another primate’s gold. One man’s slush is another animal’s snow cone.

The baboon rebel found a way through the military garbage heap’s barbed wire fence, set foot in the trash heap, and tasted the throwaways. Pay dirt. He’d hit a concentrated source of nutrition. When they came back to their home base at the end of the day, the natural-living baboons, the ones who had stuck to their traditional food-gathering strategies, to their daily grind digging up tubers, came home dusty and bedraggled, worn out by their work. But the adolescent who invented garbage raiding came back energetic, rested, strong, and glorious. As the weeks and months went by, he seemed to grow in health and vigor. Other young adolescent males became curious. Some followed the non-conformist on his daily stroll into the unknown. And, lo, they too discovered the garbage dump and found it good.

Eventually, the males who made the garbage dump their new food source began to sleep in their own group, separated from the conservative old timers. As they grew in physical strength and robustness, these Young Turks challenged the old males to fights. The youngsters’ food was superior and so was their physical power. They had a tendency to win their battles. Females attracted by this power wandered outside the ancestral troop and spent increasing amounts of time with the rebel males—who continued to increase their supply of high-quality food by inventing ways to open the door latches of the houses of the officers’ wives and taught themselves how to open kitchen cupboards and pantries and who also Invented ways to make their way through the electrified fences of farmers and gather armloads of corn. The health of the males and females in the garbage-picking group was so much better than that of the old troop that a female impregnated in the gang of garbage-pickers and farm-raiders was able to have a new infant every eighteen months. The females in the old, conservative, natural-diet group were stuck with a new infant only every 24 months. The innovators were not only humiliating the conservatives in pitch battles, they were outbreeding them.

I find the above anecdote very appealing. It seems we got to learn a lot from the social species and baboons may just be the ones we should look at more closely.

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Friday, December 14, 2007

Maslow's eight basic needs and the eight stage devlopmental model

Most of us are familiar with the Maslow's hierarchy of needs . Though we tend to think of them as five basic needs, Maslow had modified the hierarchy later to include three other needs at the top taking the total to eight. The modified diagram is given below.


Out of these the first four needs, Maslow identified as deficit needs: i.e if the needs are not met, they make us uncomfortable and we are motivated or driven by these needs in as much as we are able to sufficiently fulfill these needs.

The last four needs, he identifies as growth needs: i.e. we never get enough of these . We are constantly motivated by these needs as they pertain to our growth and development.

He also arranged them in a hierarchy such that we are motivated primarily by a need only if lower level needs have been met. Thus, before one is motivated by cognitive or self actualization needs, one should have taken care of basic deficit needs like physiological, security, belonging and esteem.

Now, everyone knows I am sold to the eight stage developmental model. As such I see clear parallels here between developmental tasks that are archived ad needs that are met.

Let me now present the eight Maslow needs and explain it using analogies form other eight stage models.

  1. Physiological needs: These are the basic animal needs for such things as food, warmth, shelter, sex, water, and other body needs. If a person is hungry or thirsty or his body is chemically unbalanced, all of his energies turn toward remedying these deficiencies, and other needs remain inactive. If one's basic biological needs are not met, one would never be able to trust the environment and would be stuck with high neuroticism and anxiety.
  2. Safety needs:With his physical needs relatively satisfied, the individual's safety needs take over and dominate his behavior. These needs have to do with man's yearning for a predictable, orderly world in which injustice and inconsistency are under control, the familiar frequent, and the unfamiliar rare. This need for consistency, if not satisfied leads to feelings of doubt and shame (as opposed to feelings of autonomy or being in control) and lead to high conscientiousness or need for discipline and orderliness.
  3. Belonging needs:After physiological and safety needs are fulfilled, the third layer of human needs is social. This psychological aspect of Maslow's hierarchy involves emotionally-based relationships in general, such as friendship, sexual intimacy and having a supportive and communicative family. If one finds failure in having such close relationships, one is bedeviled with such negative social emotions like guilt (vis a vis initiative) and has low extraversion values.
  4. Self-esteem needs: All humans have a need to be respected, to have self-esteem, self-respect, and to respect others. People need to engage themselves to gain recognition and have an activity or activities that give the person a sense of contribution, to feel accepted and self-valued, be it in a profession or hobby. This need if not satisfied leads to feelings of inferiority vis-a-vis feelings of industry. Feelings of inferiority in turn may lead to low agreeableness.
  5. Cognitive needs:Maslow believed that humans have the need to increase their intelligence and thereby chase knowledge. Cognitive needs is the expression of the natural human need to learn, explore, discover and create to get a better understanding of the world around them.This growth need for self-actualization and learning, when not fulfilled leads to confusion and identity crisis. Also, this is directly related to need to explore or the openness to experience.
  6. Aesthetic needs: Based on Maslow's beliefs, it is stated in the hierarchy that humans need beautiful imagery or something new and aesthetically pleasing to continue up towards Self-Actualization. Humans need to refresh themselves in the presence and beauty of nature while carefully absorbing and observing their surroundings to extract the beauty that the world has to offer. This need is a higher level need to relate in a beautiful way with the environment and leads to the beautiful feeling of intimacy with nature and everything beautiful.
  7. Self-actualization needs: Self-actualization is the instinctual need of humans to make the most of their abilities and to strive to be the best they can.This need when fulfilled leads to feeling of generativity.
  8. Self-transcendence needs: Maslow later divided the top of the triangle to add self-transcendence which is also sometimes referred to as spiritual needs. Spiritual Needs are a little different from other needs, accessible from many level. This need when fulfilled, leads to feelings of integrity and take things to another level of being.
I, as usual am quite excited by these parallels and implore my readers to explore this further. In my next post I will be taking about core social motives theory, which like Maslow's is a needs theory, and how that maps to the five initial stages of development.

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Thursday, December 13, 2007

Basal Ganglia: action selection, error prediction and reinforcement learning

The December edition of Dana Foundation's online brain journal , cerebrum , has a very informative and interesting piece on the role of basal ganglia in response selection, error prediction and reinforcement learning.

The article contains a primer on basic basal ganglia functions and pathways.

The basal ganglia are a collection of interconnected areas deep below the cerebral cortex. They receive information from the frontal cortex about behavior that is being planned for a particular situation. In turn, the basal ganglia affect activity in the frontal cortex through a series of neural projections that ultimately go back up to the same cortical areas from which they received the initial input. This circuit enables the basal ganglia to transform and amplify the pattern of neural firing in the frontal cortex that is associated with adaptive, or appropriate, behaviors, while suppressing those that are less adaptive. The neurotransmitter dopamine plays a critical role in the basal ganglia in determining, as a result of experience, which plans are adaptive and which are not.

Evidence from several lines of research supports this understanding of the role of basal ganglia and dopamine as major players in learning and selecting adaptive behaviors. In rats, the more a behavior is ingrained, the more its neural representations in the basal ganglia are strengthened and honed. Rats depleted of basal ganglia dopamine show profound deficits in acquiring new behaviors that lead to a reward. Experiments pioneered by Wolfram Schultz, M.D., Ph.D., at the University of Cambridge have shown that dopamine neurons fire in bursts when a monkey receives an unexpected juice reward. Conversely, when an expected reward is not delivered, these dopamine cells actually cease firing altogether, that is, their firing rates “dip” below what is normal. These dopamine bursts and dips are thought to drive changes in the strength of synaptic connections—the neural mechanism for learning—in the basal ganglia so that actions are reinforced (in the case of dopamine bursts) or punished (in the case of dopamine dips)


In particular it discusses the role of dopaminergic receptors in the GO and NoGO pathways that are involved in positive and negative reinforcement learning respectively.

Building on a large body of earlier theoretical work, my colleagues and I developed a series of computational models that explore the role of the basal ganglia when people select motor and cognitive actions. We have been focusing on how When the “Go” pathway is active, it facilitates an action directed by the frontal cortex, such as touching your pinkies together. But when the opposing “NoGo” pathway is more active, the action is suppressed. dopamine signals in the basal ganglia, which occur as a result of positive and negative outcomes of decisions (that is, rewards and punishments), drive learning. This learning is made possible by two main types of dopamine receptors, D1 and D2, which are associated with two separate neural pathways through the basal ganglia. When the “Go” pathway is active, it facilitates an action directed by the frontal cortex, such as touching your pinkies together. But when the opposing “NoGo” pathway is more active, the action is suppressed. These Go and NoGo pathways compete with each other when the brain selects among multiple possible actions, so that an adaptive action can be facilitated while at the same time competing actions are suppressed. This functionality can allow you to touch your pinkies together, not perform another potential action (such as scratching an itch on your neck), or to concentrate on a math problem instead of daydreaming.

But how does the Go/NoGo system know which action is most adaptive? One answer, we think (and as you might have guessed), is dopamine. During unexpected rewards, dopamine bursts drive increased activity and changes in synaptic plasticity (learning) in the Go pathway. When a given action is rewarded in a particular environmental context, the associated Go neurons learn to become more active the next time that same context is encountered. This process depends on the D1 dopamine receptor, which is highly concentrated in the Go pathway. Conversely, when desired rewards are not received, the resulting dips in dopamine support increases in synaptic plasticity in the NoGo pathway (a process that depends on dopamine D2 receptors concentrated in that pathway). Consequently, these nonrewarding actions will be more likely to be suppressed in the future.

It then goes on to consider the different types of learner: positive learners that have a more active GO system and negative learners that have a more active NoGO system.

This theoretical framework, which integrates anatomical, physiological, and psychological data into a single coherent model, can go a long way in explaining changes in learning, memory, and decision making as a function of changes in basal ganglia dopamine. In particular, this model makes a key, previously untested, prediction that greater amounts of dopamine (via D1 receptors) support learning from positive feedback, whereas decreases in dopamine (via D2 receptors) support learning from negative feedback.


They then experimentally manipulated the dopamine levels and verified their predictions. The experiment involved a simple game in which two symbols say A and B were paired consistently (along with other symbols say 'CD') with subjects required to choose one of them. After each choosing, the subject was given feedback as to whether he had been rewarded or punished. This feedback was not consistently related to the choice : 'A' was rewarded with positive feedback 80% of times, while 'B' was punished with negative feedback 80 % of the times. Thus though an implicit learning would happen to chose A and reject B, this rule would not be explicitly learned. Now, comes the interesting part, choose A strategy is related to positive learning and Avoid B strategy with negative learning. When these symbols A and B, in test phase were paired with new symbols say E and F respectively, subjects should have implicitly still gone with choose A and Avoid B strategy with equal inclination. Yet, administering dopamine affecting drugs had dramatic effects.

We found a striking effect of the different dopamine medications on this positive versus negative learning bias, consistent with predictions from our computer model of the learning process. While on placebo, participants performed equally well at choose-A and avoid-B test choices. But when their dopamine levels were increased, they were more successful at choosing the most positive symbol A and less successful at avoiding B. Conversely, lowered dopamine levels were associated with the opposite pattern: worse choose-A performance but more-reliable avoid-B choices. Thus the dopamine medications caused participants to learn more or less from positive versus negative outcomes of their decisions



They then go on to apply these results to Parkinson's patients.In Parkinson's patients have deficits in basal ganglia dopamine levels - especially in the NoGO pathway. Medication is L-Dopa which is a dopamine precursor and acts by increasing dopamine in the basal ganglia. They hypothesized, that people with untreated Parkinson's will be negative learners (less dopamine and less the dip), while those on medication would be positive learners 9more dopamine and more the burst).

To test this idea, we presented people with Parkinson’s disease with the same choose-A/avoid-B learning task once while they were on their regular dose of dopamine medication and another time while off it.8 Consistent with what we predicted, we found that, indeed, patients who were off the medication were relatively impaired at learning to choose the most positive stimulus A, but showed intact or even enhanced learning of avoid-B. Dopamine medication reversed this bias, improving choose-A performance but impairing avoid-B. This discovery supports the idea that medication prevents dopamine dips during negative feedback and impairs learning based on negative feedback

This notion might explain why some medicated Parkinson’s patients develop pathological gambling behaviors, which could result from enhanced learning from gains together with an inability to learn from losses.


The above (gambling in those on dopamine) I have touched earlier also, in relation to psychosis and schizophrenia, where dopamine excess is suspected. In those cases, having a consistently high dopamine level may predispose towards positive behavioral learning and positive cognitive learning. The latter may be the underlying manic loop, whereby only positively rewarded cognitions become salient, leading to a rosy picture of universe. Negatively reinforced cognitions are not registered properly and not learned/ remembered.

They then go on to discuss other implications like in ADHD, wherein the total noise in dopamine neurons may be higher, leading to both lowered positive and negative learning (my conjecture, not author's) and in addiction.

Overall a very fascinating article indeed.

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Neural correlates of trust

This is the title of a new paper in PNAS by Krueger et al, that tries to find the neural correlates of conditional and unconditional trust using the sequential, reciprocal trust game. The authors premise is that conditional trust is more costly strategy compared to unconditional trust and might utilize different brain areas as well.

Conditional trust assumes that one's partner is self-interested and estimates the expected value of one's strategy with respect to the benefits of cooperating, the risk of defection, and the future value of past decisions; it causes less balanced goodwill and results in greater variance in cooperative decisions and, therefore, is cognitively more costly to maintain. In contrast, unconditional trust assumes that one's partner is trustworthy and updates the value of one's partner with respect to their characteristics and past performance; balanced goodwill occurs more quickly, allowing the partners to attain high levels of synchronicity in their decisions and, therefore, is cognitively less costly to maintain. In this work, an examination of functional brain activity supports the hypothesis that the preferential activation of different neuronal systems implements these two trust strategies.


The results of their experiments supported their initial hypothesis and they found that while Para Cingulate cortex (PcC) activation was necessary for menatlizing and initial building of trust; later unconditional and conditional trust strategies deployed different brain areas viz Septal Area (SA) and Ventral Tegmental Area (VTA) respectively.

Unconditional trust assumes that one's partner is trustworthy. During the building stage, first movers in the nondefector group showed higher activation in the PcC compared with first movers in the defector group. Through mentalizing, partners of this group verified their prior trustworthy assumption, updated the value of one's partner's strategy with respect to their past performance, and maintained a balanced goodwill toward each other, allowing them to avoid defections. By developing "better" mental models in this early stage, partners in the nondefector group accumulated sufficient mutual goodwill to become socially attached to each other and adopted an unconditional trust strategy.

During the maintenance stage, the nondefector group showed a higher activation in the SA compared with the defector group. Across groups, pairs who showed the highest trust-reciprocate history in their decisions also showed the highest activation in this region. Furthermore, analyses of pre- and postscan behavioral ratings confirmed that only nondefector pairs felt significantly closer to each other and ranked themselves as being more of a partner to the other person after the experiment. Through early mentalizing, partners in the nondefector group must have balanced goodwill more quickly, allowing them to become synchronized in their decision patterns. Brain-to-brain correlations only increased in the SA region for the nondefector group across stages, and only partners in the nondefector group became synchronized in their SA BOLD amplitudes as first movers in adjacent trials of trust games. Synchronization in the SA led to social attachment associated with a significant decrease in activation in the PcC during the maintenance stage. By adopting this cognitively less costly strategy, decision times became significantly faster for the nondefector group across stages of the experiment.

Conditional trust assumes that one's partner is self-interested. During the building stage, first movers in the defector group showed less activation in the PcC compared with the nondefector group. Through less mentalizing in the building stage, partners in this group produced higher errors in the inferences of second movers' goodwill toward them, resulting in less balanced goodwill and, therefore, in less overall trust compared with the nondefector group. More importantly, they started to trust more in the low-payoff games and less in the high-payoff games. This decision pattern implies that defectors were adapting a conditional trust strategy by evaluating the expected value of one's strategy with respect to the risks and benefits of cooperation.

During the maintenance stage, the defector group showed higher activations in the VTA compared with the nondefector group, a region linked to the dopaminergic mesolimbic reward system providing a general reinforcement mechanism to encode expected and realized reward . Across groups, pairs who shared the lowest trust-reciprocate history in their decisions also showed the highest activation in this region. By adopting a cognitively more costly strategy, partners in the defector group showed a significant increase in activation in the PcC over the experiment. Through more mentalizing in this late stage, first movers in the defector group tried to develop more accurate models about the likelihood of their partner's choices so that they could make a more advantageous decision about when to trust. The conditional trust strategy paid off less over time as total earnings decreased for the defector group (but increased for the nondefector group) across stages.


Thus, it seems that SA, based on oxytocin and vasopressin and social bonding is a more cost-effective strategy than the VTA based on dompainerigic system based on reward monitoring.

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Wednesday, December 12, 2007

cortex maturation: found the references

In my earlier post on cortex maturation, I was unable to find the references for the claims that in Autism cortex matures earlier during toddler phase and that even in adulthood, it may be thicker.

In a recent PNAS commentary, reagarding the delay rather than deviance theory of ADHD, I came across the appropriate references to back the above observations, as well as the accelerated pruning in child-onset schizophrenia. Passing that along.

An important question is whether the delay of brain maturation is a specific characteristic of ADHD or is shared by other child psychiatric disorders. So far, none of the other major psychiatric disorders have been associated with a maturational delay of brain structure. However, to my knowledge, longitudinal structural studies have been conducted only in patients with ADHD, childhood-onset schizophrenia (COS), and autism, finding maturational deviance rather than delay. Adolescents with COS are characterized by a striking nonlinear, progressive acceleration of the normal gray matter and volume decrease in cortical regions that levels off in adulthood (22). In autism, there is an early left hemispheric overgrowth of gray and white matter at young toddler age with conflicting findings of either arrested growth or remaining brain enlargement in adolescence and adulthood (23). The findings of delayed structural brain maturation seem, thus far, to be specific to ADHD and may be an important neuroanatomic trait. However, further exploration of the developmental trajectories in other child psychiatric disorders is needed to establish the importance of a delay of brain maturation as a specific neuroanatomic marker for ADHD.
(emphasis mine, references below)
22. Greenstein D, Lerch J, Shaw P, Clasen L, Giedd J, Gochman P, Rapoport J, Gogtay N (2006) J Child Psychol Psychiatry 47:1003–1012.
23. Bashat DB, Kronfeld-Duenias V, Zachor DA, Ekstein PM, Hendler T, Tarrasch R, Even A, Levy Y, Sira LB (2007) NeuroImage 37:40–47.

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Tuesday, December 11, 2007

IQ matters...or does it?

This is just an FYI post regarding two great articles on IQ.

The first addressees the white-black IQ gap and shows that the gap is due to environmental factors and not genetic. This is a well written article by Malcom Gladwell and is strongly recommended to be read in its entirety. The arguments are manifold:

  1. Flynn effects show that IQ scores have increased over time, and hence IQ is malleable and prone to environmental influences.
  2. Intelligence is also a cultural construct and what may be intelligent behavior in one culture may be deemed stupid in another.
  3. Intelligence can be raised by providing the right socio-cultural environment and cognitive grooming and scaffolding. High heritability may partially be due to the fact that high SES groups are considered in such studies. In poor families IQ heritability drops to 10 to 20 % and environmental factors play a much higher role.
  4. IQ tests are renormed (to take care of the Flynn effect and the definition of IQ as relative to mean IQ of population) and sometimes data that supports claims like Asians have higher IQ than white which have higher than blacks are comparing apples to oranges.
  5. IQ gap is narrowing and the average scores of blacks increasing at a faster rate than whites, which is further proof that there is not a racial gap that is due to genetics.
The second article is by Flynn himself and covers some of the same ground. The main essay is followed by several commentaries and it makes for a stimulating exchange.

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Friday, December 07, 2007

Perfectionism: devleopmental influences?

A recent Mind Hacks post, and a comment by John Bunch there, set me thinking, regarding whether perfectionism could have a developmental genesis. Perfectionism , like other personality traits, would likely be having both genetic and environmental factors contributing ti its development. So, before proceeding further, I would like to list the factors of perfectionism as identified in a recent study by Frost et al, they are:

  1. Excessive concern over making mistakes
  2. The doubting of quality of one's actions
  3. High personal standards
  4. Perception of high parental expectations and criticisms
  5. A preference for order and organization

To me they present in a nice order on the five developmental factors related to trust (whether mistakes will be tolerated or not), Autonomy vs shame and doubt(doubting quality of one's actions), Initiative vs guilt (setting high standards to avoid guilt), industry vs inferiority(judging oneself by perceived parental standards) and finally Identity vs role confusion (having order and organization in life to relive the role confusion). Thus, all the perfectionist traits are a result of some deficient achieving of a developmental milestone - especially in relation to goal pursuing.

Here I come to my second theme- the comment by John Bunch, tries to draw fascinating parallels between the need to avoid mistakes in Perfectionists and the avoidance of risks in Passive Aggressives - and relates both of them to Carol Dwecks work with parsing and installing in children a fixed, entity like belief of personality and intelligence versus a growth mindset that has room for improvements and change. It is worthwhile here to recount Carol Dwecks experiments in which her team found that those children who had fixed, entity like view of intelligence gave up earlier on solving difficult tasks , avoided hard tests, weer more concerned with their image and projecting a good face than in learning - and one can easily see that these are seed for the later perfectionist traits of fear of mistakes, perceived high expectations and criticisms of parents etc. Similarly in Passive Aggressives this translates into risk avoidance - different mechanism chosen, due to underlying genetic temperaments, but to the same environmental stimuli of the fixed intelligence or talent myth installation.

By the way, the five factors of Perfectionsim can also be construed in terms of the big five factors -

  1. Neuroticism (cognitive)- worry over mistakes.
  2. Conscientiousness (motivational)- high and unrealistic standards
  3. Extraversion (behavioural) - doubt over actions
  4. Agreeableness (social)- perceived criticism and expectations
  5. Openness (exploratory) - organization and order

I would love to hear more comments on this developmental theory of perfectionism. A quick search on Google revealed a promising dissertation that links perfectionism to helpless explanatory style which fits with Dwecks theory.

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Tuesday, December 04, 2007

Rasing Successful kids

Carol Dweck, whose research I have covered extensively earlier, writes in this month's Scientific American Mind , regarding how to raise a successful child. She touches upon the entity vs incremental theories of intelligence, which she frames as fixed and innate abilities vis-a-vis a growth mindset. As per this theory having successful and intelligent children depends on not praising the children for their smarts or intelligence or talent , but on their efforts and hard work. Also, to inculcate in them a sense of brain's malleability and to view challenges as resulting in growth as a result of facing difficulties and seeing the challenges as opportunities for brain development and learning. this view purportedly leads to more motivation and effort while facing life challenges or solving educational problems. Ironically, the article is titled The Secret to Raising Smart Kids, while in my opinion , to not reinforce the 'smart' stereotype, it should have been labeled The Secret to Raising Successful Kids. this would have also captured the recent Strenberg's emphasis on successful intelligence.

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