Category Archives: Intelligence

Spatial Ability is (ONLY!) Partially Explained by Intelligence

Source: ArsTechnica, Feb 2017
<research study HERE>

different spatial tests are all basically testing the same underlying ability—and that this ability is only partly explained by general intelligence. This means that spatial ability is, to some extent, independent: you can have better (or worse) spatial ability than your general intelligence might suggest. The results also suggest that about a third of the differences in people’s spatial scores can be explained by genetics.

A team of researchers led by Kaili Rimfeld of King’s College London studied more than 1,300 pairs of twins to figure out to what extent genes contribute to spatial ability.

But first, they had to figure out which aspect of spacial reasoning to test them on. The researchers scoured the scientific literature to find all the different tests that had been used to assess spatial ability and ran pilot studies using them. They took out any tests that were too easy or difficult and any tests where the same people scored inconsistent results when taking the same test twice. The team also looked at the similarity of people’s scores in different tests—if the scores were very similar, they took out the redundant tests. By doing this, they boiled spatial ability down to 10 core tests.

Comparing the results of the identical and fraternal twin pairs found that 69 percent of the differences in spatial test results could be explained by genetic similarity. Of the remainder, the majority—23 percent—was explained by individual experience.

That only leaves a small bit of ability to be explained by the environment that the twins shared. The researchers emphasize that these estimates are unique to this population: in a less equal environment than the UK, genes might explain less of the difference.

The researchers also compared the genetic overlap with general intelligence. They found that after controlling for general intelligence, 30 percent of the differences in spatial scores could be attributed to genetic differences.


What are His Academic Credentials? Perhaps MIT, Stanford?

Source: LinkedIn, date indeterminate
<answer is at the source>


Source: Psychology Today, Mar 2017

Intelligence is the most important factor in determining long-term achievement outcomes, and personality is unlikely to compensate for background disadvantage.

Brent Roberts, professor of psychology at the University of Illinois-Urbana Champaign. His work is especially important to consider because he attempts to fully account for the role of intelligence when assessing the impact of other non-cognitive factors.

We found that both cognitive ability and personality traits are important for these outcomes in particular, but that cognitive ability differences have a larger compensatory effect than individual personality traits. … Given the independent effects of cognitive abilities and personality traits, I’d be inclined to argue that both sets of variables are important for education and income but that cognitive abilities are more important than personality traits.

For most achievement-related outcomes like education, cognitive ability is always the strongest predictor. The line that non-cognitive factors do as well or better is just wrong.

My read of the IQ to “soft outcome” literature is that it is vastly overstated.

Refuting Group Intelligence

Source:, Feb 2017

What allows groups to behave intelligently? One suggestion is that groups exhibit a collective intelligence accounted for by number of women in the group, turn-taking and emotional empathizing, with group-IQ being only weakly-linked to individual IQ (Woolley, Chabris, Pentland, Hashmi, & Malone, 2010).

Here we report tests of this model across three studies with 312 people. Contrary to prediction, individual IQ accounted for around 80% of group-IQ differences. Hypotheses that group-IQ increases with number of women in the group and with turn-taking were not supported. Reading the mind in the eyes (RME) performance was associated with individual IQ, and, in one study, with group-IQ factor scores.

However, a well-fitting structural model combining data from studies 2 and 3 indicated that RME exerted no influence on the group-IQ latent factor (instead having a modest impact on a single group test). The experiments instead showed that higher individual IQ enhances group performance such that individual IQ determined 100% of latent group-IQ. Implications for future work on group-based achievement are examined.

It is interesting also that groups did not perform better than individuals – a genuine group-IQ might be expected to enable problem solving to scale linearly (or better) with number of subjects.

In group-IQ tasks, coordination costs appear to prevent group problem-solving from rising even to the level of a single individual’s ability. This implicates not only unsolved coordination problems, which are well-known barriers to scale (Simon, 1997) but also reiterates the finding that the individual problem-solver remains the critical reservoir of creativity and novel problem solution (Shockley, 1957).

Learning Without Questioning –Why Asians do not win Nobel prizes

Source: James Thompson blog, Apr 2014

Asians (Chinese, Koreans, and Japanese) are supposed to have higher IQs (about 105 on average) than North Europeans (100), while sciences have been developed overwhelmingly by Europeans and their offshoots. Why Asians are lacking in scientific success might relate to two factors:

1. Low curiosity, which is expressed by lower Openness to experience (-.59 SD) as shown in various cross-cultural personality comparisons.

2.  Collectivism, which is captured by various individualism-collectivism indices such as the Hofstede individualism index (IDV), or Hofstede and Triandis individualism index (about -2 SD). The genetic underpinnings for these traits, such as DRD4, 5HTTLPR, and OPRM1 have also become increasingly apparent.

To integrate these psychological traits, a “q” factor is constructed by factor analysis on measures of Openness and Collectivism, which are then correlated with variables measuring academic achievements and also student assessments. It is found that IQ scores coupled with “q” factor scores neatly predict racial scientific achievements and also world-wide student assessments.  

Google DOC presentation: 

A Mathematical Understanding of Intelligence

Related Resource: Offtopicarium, Jan 2013


Neuroscience of Intelligence

Source: James Thompson posting on, Jan 2017

Only 4% of the white population can do all the tasks in the list. 21% get to the 4th level but cannot do carpet cost type problems, and at the very bottom 14% have very simple skills, which do not include locating an intersection on a street map. For many of you reading this, the finding will seem incredible. It is incredible. Human differences are hard to believe, but they are matters to be demonstrated, beliefs notwithstanding.

In a large Dutch twin study (Posthuma et al ., 2003b ),the same identical twins were given mental test batteries repeatedly over time to assess general intelligence. The heritability estimate of general intelligence was 26% at age 5, 39% at age 7, 54% at age 10, 64% at age 12, and starting at age18 the estimate grew to over 80%. The increases could be due to several factors including more genes “turning on” with increasing age or gene– environment interactions.

in a study of 641 Brazilian school children, SES did not predict scholastic achievement, but intelligence test scores did (Colom & Flores-Mendoza, 2007). An even larger classic study had data on 155,191 students from 41 American colleges and universities. Their analyses showed that SAT scores predicted academic performance about the same even after SES was controlled; that is, SES added no additional predictive power (Sackett et al ., 2009 )

In 1988 Haier published the first PET study of students taking the Raven’s Matices test, showing that the brains of such students differed in terms of areas activated from those students doing a simpler attention task. In a master-stroke he correlated the Raven’s scores with brain activity, showing that the brightest students showed less brain activity. That’s right: less activity. Hence my frequent advice to earnest people who want to use more of their brain, which is that they should be bright enough to use less of their brain. Why sweat the small stuff?

Haier and colleagues proposed the brain efficiency hypothesis of intelligence:higher intelligence requires less brainwork.