genetics
A gene that affects episodic memory?
Oct 27th
A tantalizing study, published in Science, indicates that a SNP in a single gene KIBRA, could lead to a difference of as big as 25% in the outcome of a free recall test measuring the episodic memory. The KIBRA gene is expressed in the medial temporal lobe (the hippocampal region) and using fMRI the authors were able to demonstrate different levels of activation in this brain area for the carriers versus non-carriers of the T allele when they were engaged in a retrieval task.
Human memory is a polygenic trait. We performed a genome-wide screen to identify memory-related gene variants. A genomic locus encoding the brain protein KIBRA was significantly associated with memory performance in three independent, cognitively normal cohorts from Switzerland and the United States. Gene expression studies showed that KIBRA was expressed in memory-related brain structures. Functional magnetic resonance imaging detected KIBRA allele–dependent differences in hippocampal activations during memory retrieval. Evidence from these experiments suggests a role for KIBRA in human memory
This is an important work and could lead to much insight on the memory formation mechanisms involved.
Hat Tip: Small Gray Matters
More From TheMouseTrap
TheMouseTrap Recommends
Gender bias in Math skills : a case of Traits Vs. Environment/Effort feedback?
Oct 26th
A recent news article reports on a study that demonstrates that the gender bias in Math abilities may be due to environmental and cultural effects – specifically as a result of the negative self- perception garnered by the activation of the negative stereotype of women as having grossly inferior mathematical abilities than men.
The experiment involved giving 220 female study participants bogus scientific explanations for alleged sex differences in math and then having them write math tests. Those who were given a ‘nature’ explanation – that women have differential genetic composition than men and the cause of their low maths abilities was genetic and gender based – performed poorly on the Math tests compared to the group that was told that their math skills depended on how they were raised and were given a ‘nurture’ explanation and an experiential account of the sex differences such as math teachers treating boys preferentially during the first years of math education.
In the control condition some females were told that no sex differences exist while another group was reminded (primed) of the stereotype about female math under-achievement.
The worst performance was for genetic explanation females, followed by ‘stereotype primed’ females. Those who were given an experiential explanation performed as well or better than the control group that received the feedback that there were no sex differences in Math abilities.
While the authors analyze and explain the results in terms of the ‘Stereotype theory’ – that genetic explanations lead to more negative stereotypes and that activation of the negative stereotype affects performance- a more parsimonious explanations is that the differences can be explained by the same differential outcomes that are observed in people who have a genetic or trait-like versus an effort-driven or skill-like view of abilities. I have discussed previously how these differential view of abilities may develop and the experiment above has just the right conditions to induce such a differential view.
Those who were given a genetic explanation of sex differences in math abilities, may have formed a trait-like view of Math ability and were prone to see the ability as stable, genetic and immutable. This is the same view of math ability that would be formed if they had been given generic feedback – like “you are a math prodigy”.
Those who had been given experiential explanations of sex differences would have been more prone to form a skill-like view of math abilities and assume that the ability could be improved and honed based on environmental inputs like proper teaching, guidance, strategy or efforts. This would have been the case if they had been given ‘specific’ feedback – like “you solved this math problem very well this time”.
It is evident that a large part of the difference in the math test results observed in genetic vs experiential explanation conditions can be explained by the different view about math abilities that these experiments had induced. Those who were having the trait-like view of math ability would get frustrated while tackling a difficult problem and would be less resilient and effort-full while tackling the latter, more easy, problem on the test; as they would have formed a negative self-perception as one who has little mathematical talent. On the other hand, those who had been induced to form a skill-like view of math ability, would have been more resilient and effort-full when tackling latter problems, despite some early failures, as a failure would not have led to a resigned sate of mind, but would have only resulted in a belief that the strategies or effort or earlier training had not been sufficient to solve the particular problem.
It is not my contention that negative stereotype activation has no role to play- priming with stereotype words does lead to measurable effects on performance – but in this case, even if the stereotype activation is involved, the stereotype may be instrumental in activating the differential view of mathematical abilities and its effects mediated by the effects that such views have on test performances.
More From TheMouseTrap
- The Five Core Social Motives
- A new issue of the Tangled Bank
- Primate evolutionary tree: a case of eight stage evolution leading to humans?
TheMouseTrap Recommends
Mouse research: Genetic footprints of anxiety?
Oct 19th
A recent study, has determined that a Single Nucleotide Polymorphism (SNP) in the BDNF (Brain deriver neurotopic factor) gene in humans, that substitutes a Met allele for Val, may be a predictor for increased susceptibility to anxiety/ depression. The study involved experiments with mouse homozygous for the Met allele and placing them in stressful situations. These mice exhibited considerable increase in anxiety over normal mouse when facing similar situations. Thus, a potential locus and mechanism for anxiety/ depression has become available.
It is interesting to note that a similar SNP that involves Met/Val substitution in the COMT gene has been implicated in schizophrenia and affects cognitive performance in frontal regions. In the COMT case though, those who have the Met allele are more fortunate, in the sense that the Val allele causes increased metabolism of dopamine and other catecholamines.
While a Met allele is good in a Schizophrenia gene, it has the reverse effect in a depression/anxiety gene! What exactly does the Met / Val difference mean for a gene?
Hat Tip: The Mind Blog
More From TheMouseTrap
TheMouseTrap Recommends
Belief about Intelligence : how it affects performance and how it is formed
Oct 16th
Affective Teaching keeps posting some interesting basic cognitive tutorials and their latest one deals with the different concepts people have regarding intelligence and how that affects performance and attitudes.
As per that tutorial, people can either have fixed (entity) or trait-like view of intelligence/ abilities or a changeable (incremental) or skill-like view of intelligence/ abilities. Interestingly, those with fixed view are more prone to learned helplessness, external locus of control, less persistence and lack of use of learning strategies. On the other hand those with changeable view of intelligence are more persistent, having a mastery goal or orientation and apt to use learning strategies and credit success to effort and strategy.
This same difference in attitudes and outcomes was predicted by my recent blog post where I analyzed the differential effects of providing generic (person based) versus specific (outcome based) feedback and praise. It was surmised that this would lead to differential view of intelligence/abilities as being trait-like or skill-like in nature. It is heartening to note that existing research supports such a differentiation in the conceptualization of intelligence by individuals and also predicts accurately the different outcomes based on different underlying conceptualizations.
It should thus be clear that providing the right sort of feedback to the child is very important so that they hook on to the right conceptualization of intelligence early on. This may also go long way in settling the expertise debate: genius have a mastery orientation and an incremental view of intelligence which is different form the normal trait-like view held by most people. Thus, it is not just the case that that they are either more talented or just better learners (although they are both) ; they also have a different attitude- and a different underlying concept of intelligence/ability- which is very much a result of the environmental feedback they received in childhood ans is instrumental in making them what they are.
More From TheMouseTrap
- The Mouse is dreaming that it is in a Trap!!
- BAD09: the Psychology of trading carbon emissions and why it is misguided.
- A gene that affects episodic memory?
TheMouseTrap Recommends
Is low IQ the cause of income inequality and low life expectancy or is it the other way round?
Oct 16th
As per this post from the BPS research digest, Kanazawa of LSE has made a controversial claim that economic inequality is not the cause of low life expectancy, but that both low life expectancy and economic inequality are a result of the low IQ of the poor people. The self-righteous reasoning is that people with low IQ are not able to adapt successfully to the stresses presented by modern civilization and hence perish. He thinks he has data on his side when he claims that IQ is eight times more strongly related to life expectancy, than is socioeconomic status. What he forgets to mention(or deliberately ignores) is growing evidence that IQ is very much determinant on the socioeconomic environment of its full flowering and a low IQ is because of two components- a low genetic IQ of parent plus a stunted growth of IQ/intelligence due to impoverished environment available because of the low socio-economic status of the parents.
A series of studies that I have discussed earlier, clearly indicate that in the absence of good socioeconomic conditions, IQ can be stunted by as large as 20 IQ points. Also discussed there, is the fact that the modern civilization as a whole has been successful in archiving the sate of socioeconomic prosperity that is sufficient for the full flowering of inherent genetic IQ of a child and as such the increments in IQ as we progress in years and achieve more and more prosperity (the Flynn effect) has started to become less prominent. This fact also explains the Kanazawa finding that in ‘uncivilized’ sub-Saharan countries the IQ is not related to life expectancy, but socio-economic status is. although, he puts his own spin on this data, a more parsimonious ( and accurate) reason for this is that in the sub-Saharan countries, even the well -of don’t have the proper socio-economic conditions necessary for the full flowering of IQ and thus the IQ of both the well-off and poor parents in these countries is stunted equally. Thus, the well-off (which are not really that well-off in comparison to their counterparts in the western countries) are not able to be in any more advantageous position (with respect to IQ) than the poor in these countries. The resultant life expectancy effect is thus limited to that directly due to economic inequality and the IQ mediated effect of economic inequality is not visible.
What Kanazawa deduces from the same data and how he chooses to present these findings just goes on to show the self-righteous WASP attitude that many of the economists assume. After reading Freakonomics, and discovering how the authors twist facts and present statistics in a biased manner to push their idiosyncratic theories and agendas, it hardly seems surprising that another economist has resorted to similar dishonest tactics – shocking people by supposedly providing hard data to prove how conventional wisdom is wrong. Surprisingly, his own highlighting of sub-Saharan counties data that shows that life-expectancy is highly dependent on socio-economic conditions in these countries is highly suggestive of the fact that in cultures where the effects og economic inequality are not mediated via the IQ effects, economic inequality is the strongest predictor of low life expectancy.
Instead of just blaming the people for their genes/ stupidity, it would be better to address the reasons that lead to low IQs and when they are tackled, directly address the social inequality problem , as in the author’s own findings, when IQ is not to blame for the low life expectancy, the blame falls squarely on economic inequality (as in the sub-Saharan countries data) .
More From TheMouseTrap
- Depression and Mania: The Bipolar thinking style
- Blog Action Day: Poverty and IQ: from the archives
- IQ and Religion: is the relation mediated by wealth and feelings of control?
Recent Comments