individual differences

Infectious disease burden may be a major factor in determining national IQ differences

July, 2010

Analysis of global data shows that differences in national IQs are most strongly predicted by the country's infectious disease burden.

A new analysis of data first published in 2002 in a controversial book called IQ and the Wealth of Nations and then expanded in 2006, argues that national differences in IQ are best explained not by differences in national wealth (the original researchers’ explanation), but by the toll of infectious diseases. The idea is that energy used to fight infection is energy taken from brain development in children. Using 2004 data on infectious disease burden from the World Health Organization, and factors that have been linked to national IQ, such as nutrition, literacy, education, gross domestic product, and temperature, the analysis revealed that infectious disease burden was more closely correlated to average IQ than the other variables, alone accounting for 67% of the worldwide variation in intelligence. The researchers also suggest that the Flynn effect (the rise in IQs seen in developed countries during the 20th century) may be caused in part by the decrease in the intensity of infectious diseases as nations develop.

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[1619] Eppig, C., Fincher C. L., & Thornhill R.
(2010).  Parasite prevalence and the worldwide distribution of cognitive ability.
Proceedings of the Royal Society B: Biological Sciences.

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Cognitive ability, not age, predicts risky decisions

July, 2010

A new study provides evidence that it's not age per se that affects the quality of decision-making, but individual differences in processing speed and memory.

A study involving 54 older adults (66-76) and 58 younger adults (18-35) challenges the idea that age itself causes people to become more risk-averse and to make poorer decisions. Analysis revealed that it is individual differences in processing speed and memory that affect decision quality, not age. The stereotype has arisen no doubt because more older people process slowly and have poorer memory. The finding points to the need to identify ways in which to present information that reduces the demand on memory or the need to process information very quickly, to enable those in need of such help (both young and old) to make the best choices. Self-knowledge also helps — recognizing if you need to take more time to make a decision.

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1 in 40 of us really can multitask

March, 2010

A study assessing multitasking ability has found that a very few (5 out of 200) were unaffected by doing two complex tasks simultaneously (indeed their performance on the memory task improved!).

A study assessing the performance of 200 people on a simulated freeway driving task, with or without having a cell phone conversation that involved memorizing words and solving math problems, has found that, as expected, performance on both tasks was significantly impaired. However, for a very few, performance on these tasks was unaffected (indeed their performance on the memory task improved!). These few people — five of them (2.5%) — also performed substantially better on these tasks when performed alone.

Reference: 

Watson, J.M. & Strayer, D.L. 2010. Supertaskers: Profiles in extraordinary multitasking ability. Psychonomic Bulletin and Review. In Press.

Full text is available at http://www.psych.utah.edu/lab/appliedcognition/publications/supertaskers...

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The secret of sharp memory in old age

March, 2010

Examination of the brains from 9 “super-aged” — people over 80 whose memory performance was at the level of 50-year-olds — has found that some of them had almost no tau tangles. Are they genetically protected, or reaping the benefits of a preventive lifestyle?

Examination of the brains from 9 “super-aged” — people over 80 whose memory performance was at the level of 50-year-olds — has found that some of them had almost no tau tangles. The accumulation of tau tangles has been thought to be a natural part of the aging process; an excess of them is linked to Alzheimer’s disease. The next step is to work out why some people are immune to tangle formation, while others appear immune to the effects. Perhaps the first group is genetically protected, while the others are reaping the benefits of a preventive lifestyle.

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The findings were presented March 23 at the 239th National Meeting of the American Chemical Society (ACS).

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Foster care associated with improved growth, intelligence compared to orphanage care

April, 2010

A study involving healthy institutionalized infants from six Romanian orphanages has found that those randomly assigned to a foster care program showed rapid increases in height and weight, and that this was associated with better caregiving quality and significantly improved verbal IQ.

A study involving 136 healthy institutionalized infants (average age 21 months) from six orphanages in Bucharest, Romania, has found that those randomly assigned to a foster care program showed rapid increases in height and weight (but not head circumference), so that by 12 months, all of them were in the normal range for height, 90% were in the normal range for weight, and 94% were in the normal range of weight for height. Caregiving quality (particularly sensitivity and positive regard for the child, including physical affection) positively correlated with catch-up. Children whose height caught up to normal levels also appeared to improve their cognitive abilities. Each incremental increase of one in standardized height scores between baseline and 42 months was associated with an average increase of 12.6 points in verbal IQ.

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Morningness a predictor of better grades in college

January, 2008

A survey of 824 undergraduate students has found that those who were evening types had lower average grades than those who were morning types.

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The finding was presented at SLEEP 2008, the 22nd Annual Meeting of the Associated Professional Sleep Societies (APSS).

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