Notes from Study on Intelligence

During No Internet November I had plenty of time to go through some of my heavier bookmarks. Jordan Peterson tweeted this study somewhere in October and it caught my eye, as I was wondering of ways to elevate intelligence mean of society in the past.

Study on Intelligence

Study on Intelligence: Intelligence. New Findings and Theoretical Developments.

Authors: Richard E. Nisbett University of Michigan
Joshua Aronson and Clancy Blair New York University
William Dickens Northeastern University
James Flynn University of Otago
Diane F. Halpern Claremont McKenna College
Eric Turkheimer University of Virginia

Key notes from study

Key points from reading this study:

• “An important distinction commonly made in the literature is between crystallized intelligence, g(C), or the individual’s store of knowledge about the nature of the world and learned operations such as arithmetical ones which can be drawn on in solving problems, and fluid intelligence, g(F), which is the ability to solve novel problems that depend relatively little on stored knowledge as well as the ability to learn. A test that is often considered the best available measure of g(F) is Raven’s Progressive Matrices.”
• Environment has a far greater importance on intelligence than previously thought. Environment mainly meaning socioeconomic status in which children are being raised.
• Flynn Effect is not stopping. The gap between developed and developing nations is closing.
• Inbreeding lowers IQ scores.
• With age g(F) degenerates, while g(C) tends to increase.
• “A meta-analysis of a large number of studies has shown that aerobic exercise, at least for the elderly, is very important for maintaining IQ, especially for executive functions such as planning, inhibition, and scheduling of mental procedures (Colcombe & Kramer, 2003). The effect of exercise on these functions is more than 0.5 SD for the elderly (more for those past age 65 than for those younger). It is possible to begin cardiovascular exercise as late as the seventh decade of life and substantially reduce the likelihood of Alzheimer’s disease (Aamodt & Wang, 2007).”
• Games like “Lumocity” do not increase fluid intelligence, they merely train brain to perform better on that game.
• “No evidence was found for sex differences in the mean level of g or in the variability of g… . Males, on average, excel on some factors; females on others” (Jensen, 1998, pp. 531–532). Jensen’s conclusion that no overall sex differences exist for intelligence has been bolstered by researchers who assessed intelligence with a battery of 42 mental ability tests (Johnson & Bouchard, 2007). They found that most of the tests showed little or no sex differences. There were, however, several tests that showed a difference between males and females of 0.5 SD or more. These differences included an advantage for females for verbal abilities such as fluency and memory abilities and an advantage for males on visuospatial abilities such as object rotation.”
• “Exercise of particular skills increases the size of particular areas of the brain. The hippocampus mediates navigation in three-dimensional space. London taxicab drivers have hippocampi that are enlarged—and enlarged in proportion to the amount of time they have been on the job (Maguire et al., 2000). Similarly, the process of learning how to juggle over a three-month period increased the size of gray matter in the mid-temporal area and the left posterior intra-parietal sulcus (Draganskiet al., 2004). The extent of structural gray matter growth was correlated with increased juggling ability. Three months after ceasing to juggle, the size of gray matter expansions was reduced. Three months of playing the visual-spatial game Tetris resulted in increases in cortical thickness in two regions and also in functional changes (though functional changes were not in the same areas as structural changes; Haier, Karama, et al., 2009).”
• Self-regulation/self-discipline, ability to delay gratification are linked to higher IQ and a good predictors of academic achievement and life outcomes. “[…]individuals with larger working memory capacities are better able to regulate their emotions (Schmeichel, Volokhov, & Demaree, 2008), and individuals who are better able to suppress their emotions have higher scores than their more impulsive peers on the Raven’s Progressive Matrices, a standard measure of g(F)”.
• “There are many more mentally retarded (i.e., IQ below 70) males than females, which suggests an X-linked genetic locus for many categories of mental retardation. A review of the literature placed the ratio of males to females at 3.6:1 across several categories of mental retardation (Volkmar & Sparrow, 1993). Males are also more variable in their performance on some tests of quantitative abilities, which results in more males at both the high and low ends of the distribution.”
• Chronic stress erodes the body. Including brain function. “One factor that Neisser and colleagues (1996) did not deal with extensively is stress. Chronic, continuous stress— what can be considered as “toxic” stress—is injurious over time to organ systems, including the brain. Chronically high levels of stress hormones damage specific areas of the brain—namely, the neural circuitry of PFC and hippocampus—that are important for regulating attention and for short-term memory, long-term memory, and working memory”
• Research suggests racial gap in IQ is highly contributed “to the fact that Blacks, on average, tend to live in more stressful environments than do Whites. This is particularly the case in urban environments, where Black children are exposed to multiple stressors.”