What is “Cultural IQ” training and does it really work?

IQ was once the only game in town. Now it rubs shoulders with a gaggle of human ability measures such as Emotional Intelligence, Empathy Quotient, and Rationality Quotient. The increasingly interconnected and diverse world of work has magnified interest in another newcomer: CQ, or cultural intelligence. With it come courses promising to prepare their students to work with colleagues, partners and customers who have different values and norms. A new paper investigates how effective this training really is.

The researchers, led by Jacob Eisenberg, investigated cultural awareness training that had a narrow, academic focus, predicting that its impact should be limited to the more intellectual aspects of CQ: cognitive CQ (spotting trends and gathering explicit knowledge on how cultures work), and metacognitive CQ (awareness of what you do and don’t know about other cultures). The training involved lectures and seminars led by professors in the manner of a traditional academic program; these cost-effective methods reflect those typically used in this educational industry.

The first study involved students (mostly Austrians) on a Study Abroad programme intended to increase their language knowledge, expose them to different cultures, and introduce them to different teaching methods. Students on this programme also completed a 3-day cultural management course. At the end of the course, the students rated themselves significantly improved at cognitive and meta-cognitive elements, but not at the other aspects of CQ, including motivational CQ (the amount of emotional resources put towards cultural sensitivity), and behavioural CQ (adopting behaviours such as appropriate tone of voice or recognising personal space).

This finding was replicated in a second study with a more diverse sample of students from 46 nationalities, who received short slots of training spread over several months as part of their International Management Masters.

Eisenberg’s team predicted that participants who had lived in more countries (with minimum stays of six months) should have higher CQ than their more sheltered peers, but that training should close this gap. This was partially borne out. In Study 1, residence history was more strongly correlated with pre-training than post-training levels of cognitive and metacognitive CQ. Meanwhile, the correlation between residence history and motivational CQ was unchanged by the training, strengthening the hypothesis that academic CQ training influences only cognitive aspects. In Study 2, which showed generally weaker effects (perhaps these more international students had less to gain from the training) these trends didn’t reach significance.

The second study also included a no-training control group, who failed to show the benefits enjoyed by the CQ training group. However, it’s a shame that the matching was poor - the controls were retested after three weeks, whereas for the training group eight weeks on average elapsed before retesting. Perhaps the CQ boost was only found in the training group because they spent five extra weeks on their Masters course, surrounded by students from diverse cultures, before they were finally tested?

Looking across the evidence, there’s a good case for claiming that cognitive elements of cultural intelligence can be selectively developed through academic training, including being conscious of how much you don’t yet know about other cultures. But such training doesn’t seem to help people to actually alter behaviour, nor to maintain an appetite for ambiguous cultural environments, arguably even more vital to adapting to a culture. Methods matter, and if you want people to feel or act differently, traditional teaching seems unlikely to be enough, however convenient it may be for the industry to provide.
 _________________________________


Eisenberg, J., Lee, H., Bruck, F., Brenner, B., Claes, M., Mironski, J., & Bell, R. (2013). Can Business Schools Make Students Culturally Competent? Effects of Cross-Cultural Management Courses on Cultural Intelligence Academy of Management Learning & Education, 12 (4), 603-621 DOI: 10.5465/amle.2012.0022

Post written by Alex Fradera (@alexfradera) for the BPS Research Digest.

The benefits of thinking about our ancestors

Psychologists have shown previously that thinking about our own mortality - 'where we're going' - prompts us to shore up our cultural world view and engage in self-esteem boosting activities. Little researched until now, by contrast, are the psychological effects of thinking about where we came from - our ancestors.

Anecdotally, there's reason to believe that such thoughts are beneficial. Why else the public fascination with genealogy and programmes like the BBC's Who Do You Think You Are? Now Peter Fischer and his colleagues at the Universities of Graz, Berlin and Munich have shown that thinking about our ancestors boosts our performance on intelligence tests - what they've dubbed 'the ancestor effect'.

'Normally, our ancestors managed to overcome a multitude of personal and society problems, such as severe illnesses, wars, loss of loved ones or severe economic declines,' the researchers said. 'So, when we think about them, we are reminded that humans who are genetically similar to us can successfully overcome a multitude of problems and adversities.'

An initial study involved 80 undergrads spending five minutes thinking about either their fifteenth century ancestors, their great-grandparents or a recent shopping trip. Afterwards, those students in the two ancestor conditions were more confident about their likely performance in future exams, an effect that seemed to be mediated by their feeling more in control of their lives.

Three further studies showed that thinking or writing about their recent or distant ancestors led students to actually perform better on a range of intelligence tests, including verbal and spatial tasks (in one test, students who thought about their distant ancestors scored an average of 14 out of 16, compared with an average of 10 out of 16 among controls). The ancestor benefit was mediated partly by students attempting more answers - what the researchers called having a 'promotion orientation'.

These benefits weren't displayed by students in control conditions that involved writing about themselves or about close friends. Moreover, the ancestor effect exerted its benefit even when students were asked to think about negative aspects of their ancestors.

'We showed that an easy reminder about our ancestors can significantly increase intellectual performance,' the researchers said. 'Hence, whenever people are in a situation where intellectual performance is extraordinarily important, for example in exams or job interviews, they have an easy technique to increase their success.'

Fischer and his colleagues emphasised their research is at an exploratory phase. Future work is needed to find out what other benefits thinking of ancestors might have, and also to uncover other possible mediating factors, which they speculated might have to do with 'processes of social identity, family cohesion, self-regulation or norm activation elicited by increased ancestor salience.'
_________________________________

Fischer, P., Sauer, A., Vogrincic, C., and Weisweiler, S. (2010). The ancestor effect: Thinking about our genetic origin enhances intellectual performance. European Journal of Social Psychology DOI: 10.1002/ejsp.778

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Related article from The Psychologist magazine: What factors drive a person to research a family tree, or an adoptee to search for their biological parents?

Higher intelligence associated with "thinking like an economist"

As the world economy dusts itself down and edges towards recovery, a provocative new paper claims that people with higher intelligence are more likely to think like economists. That is, they're more likely to be optimistic about the economy; to recognise the economic advantages of markets free from government interference, and the advantages of foreign trade and foreign workers; and to appreciate the economic benefits of achieving greater productivity with less man-power. The lead author is Bryan Caplan, an economics professor at George Mason University. Past essays by him include 'The 4 Boneheaded Biases of Stupid Voters (And we're all stupid voters.)'

Prior research has established that the more time a person spends in education, the more likely their broad economic views are to match that of the typical economist (pdf). Caplan and his colleague Stephen Miller point out that these studies failed to take into account the influence of intelligence. After all, it's known that people with higher IQ tend to spend longer in education and intelligence itself may also directly influence economic beliefs.

To overcome this problem, Caplan and Miller have focused on answers to the General Social Survey, a massive US poll of national opinions performed every two years. Crucially, it includes questions about the economy and a small test of verbal IQ.

Caplan and Miller's finding is that the link between educational background and 'thinking like an economist' is weakened when IQ is taken into account because IQ is the more important factor associated with economic beliefs. It's a complicated picture because IQ and education may be mutually influential. However, if one assumes that education is unable to raise IQ, but that IQ affects time spent in education, then the researchers said 'the net effect on economic beliefs of intelligence is more than double the net effect of education.' Even if one assumes that education can also affect IQ, 'intelligence still has a larger estimated effect [on economic beliefs],' they said.

Does the link between higher intelligence and 'thinking like an economist' mean that economists are generally right and the public wrong? In answer to this question, Caplan and Miller cite Shane Frederick, a decision-making scholar at Yale's School of Management, who's previously argued that it depends on the type of question. For financial issues, he argued, it pays to emulate those 'with higher cognitive abilities'. However, Frederick noted that 'if one were deciding between an apple or an orange, Einstein's preference for apples seems irrelevant.'

Caplan and Miller say they agree with Frederick about this, before concluding boldly: 'The fact that the beliefs of economists and intelligent non-economists dovetail is another reason to accept the "economists are right, the public is wrong" interpretation of lay-expert belief gaps.'
_________________________________

Caplan, B., and Miller, S. (2010). Intelligence makes people think like economists: Evidence from the General Social Survey. Intelligence, 38 (6), 636-647 DOI: 10.1016/j.intell.2010.09.005

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Flynn effect for memory could invalidate neuropsychologists' tests

In Western countries, scores on IQ tests have been rising for several decades - the Flynn effect, named after the political scientist James Flynn. Now Sallie Baxendale at the Institute of Neurology has provided evidence that a similar effect has occurred for the standardised memory tests that are used by clinical neuropsychologists, a finding with implications for the diagnosis of memory problems in contemporary patients.

Baxendale focused on the Adult Memory and Information Processing Battery (AMIPB) - 'the most commonly used memory battery amongst clinical neuropsychologists in the UK' - published in 1985, and its successor, the Brain Injury Rehabilitation Trust Memory and Information Processing Battery (BMIOB), published in 2007. The two tests feature different wording and design but they both make equivalent demands: learning and recalling lists of words, and learning and recalling abstract line drawings.

Baxendale compared the performance of the two participant samples that provided the original normative data (the 'norms') for the two tests. These are the healthy participants, spanning four age ranges, whose average performance provides the benchmark for assessing patients. The normative data for the AMIPB was provided in 1985, or thereabouts, by 184 British people aged 18 to 75; the normative data for the BMIPB was collected in 2007 or thereabouts from 300 British people aged 16 to 89.

On one hand, there was little evidence of any difference in average performance on verbal learning and recall between the 1985 and 2007 samples (the exceptions were verbal learning in the 31-45 years age range and verbal recall in the oldest age range, both of which were superior in the 2007 sample). By contrast, visual learning and recall were both superior in the 2007 sample compared with the 1985 sample, at all four age ranges: 16-30; 31-45; 46-60; and 61-75. This is consistent with the traditional Flynn effect, which is most pronounced for non-verbal intelligence tests.

Baxendale said her findings have implications for diagnosis because present-day patients may, pre-trauma or pre-illness, have had elevated non-verbal learning and recall scores in comparison to the old normative data. Therefore, such patients could be impaired relative to their own healthy baseline, and yet appear unaffected compared with the out-of-date normative data. 'This may present a confound for neuropsychologists concerned with the lateralising and localising significance of memory test profiles,' Baxendale said.
_________________________________

Baxendale, S. (2010). The Flynn effect and memory function. Journal of Clinical and Experimental Neuropsychology, 32 (7), 699-703 DOI: 10.1080/13803390903493515

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Training in emotional intelligence actually works

A new study shows that training in emotional intelligence (EI) - the ability to understand and manage one's own and other people's emotions - actually works. Delphine Nelis and colleagues said their finding has profound implications given the number of positive outcomes, including improved health and occupational success, that are known to be associated with having greater emotional intelligence (one recent study even linked EI to orgasm frequency in women!)

Nineteen students undertook the training, whilst 18 others formed a control group and carried on life as normal. The training - 4 weekly sessions lasting 2.5 hours each plus homework - was theoretically grounded and aimed to improve the understanding of emotions, identifying emotions, expressing and using emotions and managing emotions.

After training and at 6-month follow-up, the training students but not the control students showed improvements in aspects of "trait" emotional intelligence normally considered immutable, including improvement in emotion identification and emotion management (of self and others' emotions). Surprisingly perhaps, "emotional understanding" showed no improvement.

"Overall these results are promising," the researchers said, "as they suggest that, with a proper methodology relying on the latest scientific knowledge ... some facets of EI can be enhanced but not all."

Nelis and her colleagues said their findings could have potential application in health, educational and organisational settings but they acknowledged their study had a number of major limitations. These include the fact that the control group undertook no special activity, so any effects observed for the EI training could be caused by non-specific factors, such as the simple benefit that can come from taking part in group activities.
_________________________________

Nelis, D., Quoidbach, J., Mikolajczak, M., & Hansenne, M. (2009). Increasing emotional intelligence: (How) is it possible? Personality and Individual Differences, 47 (1), 36-41 DOI: 10.1016/j.paid.2009.01.046

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Has average intelligence started to decline?

After years on the increase, average intelligence test performance could be in decline. That's according to Thomas Teasdale and David Owen who took advantage of the Danish tradition of testing the intelligence of all 18-year-old men being considered for conscription into military service.

Consistent with the observed world-wide increase in average intelligence - the Flynn Effect - the 25,000 young men assessed for military service in Denmark in 1999 performed significantly better, by about 2 IQ points, than the 33,000 tested in 1988. However, the 23,000 men tested in 2003/2004 performed significantly worse than the 1998 group, at a level almost equivalent to the 1988 cohort. This apparent decline in average intelligence matches a similar observation made in Norway among their conscripts.

So what's causing this reversal in braininess? Teasdale and Owen rule out any effect of diet - after all, there's been no change in average height, which would be expected to suffer if diet quality had deteriorated.

Prior research found that test performance was higher among those men with a negative attitude towards military service. On that basis, Teasdale and Owen also reject the suggestion that the decline could be due to malingering - that is, deliberate poor performance on the intelligence test to avoid military service.

Instead, the researchers surmise that the performance decline is due to "some qualitative change in the emphasis on abstract reasoning and problem-solving within the Danish educational system or a decreased emphasis on speed". They also cite a rising proportion of immigrants in the young population as another possible contributing factor.

Finally, Teasdale and Owen noted that with average intelligence test scores beginning to rise in developing countries, the decline observed here, if representative of a larger pattern, could mark the beginning of the end for any observed differences in average IQ test scores between nations.
_________________________________

TEASDALE, T., OWEN, D. (2008). Secular declines in cognitive test scores: A reversal of the Flynn Effect. Intelligence, 36(2), 121-126. DOI: 10.1016/j.intell.2007.01.007

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Robert the Bruce's skull size shows he had high IQ

In a paper featuring an irresistible mix of history and psychology, researchers have estimated Robert the Bruce's IQ from his skull size and concluded that he was a highly intelligent man.

Ian Deary and colleagues first established the relationship between IQ and skull size among 48 men (aged 71-76) living in Edinburgh. The researchers scanned the men's brains using MRI and had them complete the National Adult Reading Test, known to be strongly related to full IQ test performance and designed especially for use with older participants.

Consistent with past research showing that head size and brain volume correlate with IQ, the new analysis revealed that skull size was significantly related to the men's IQ.

Next, the researchers scanned and measured a plaster cast of Robert the Bruce's skull, as well as measuring its size with callipers (see image above). Extrapolating from the statistical relationship between skull size and IQ found among the Edinburgh participants, the researchers estimated that Robert the Bruce, with his larger than average skull, had an impressive IQ of about 128, and possibly higher.

This would make Robert Bruce of similar intelligence to other military leaders as estimated by Catharine Cox in 1926, including Cromwell with an estimated IQ of 135, Napoleon at 145 and Washington at 140.

Robert Bruce is famed for his defeat of a full English army led by Edward II at Bannockburn in 1314, as well as his later efforts to consolidate Scotland's international position, culminating with the declaration of Arbroath in 1320.

"The IQ estimate for Robert Bruce accords with his military, political and intellectual achievements, especially given the highly personal nature of kingship in the Mediaeval period," the researchers concluded.
_________________________________

Deary, I.J., Ferguson, K.J. Bastin, M.E., Barrow, G.W.S., Reid, L.M., Seckl, J.R., Wardlaw, J.M. & MacLullich. (2007). Skull size and intelligence, and King Robert Bruce's IQ. Intelligence, 35, 519-525.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Image credit and copyright: Ian Deary.

Feigning mental retardation

When Daryl Atkins was convicted of abduction and murder, the jury sentenced him to death. But Atkins was mentally retarded, with an IQ of 59, and following several appeals, in the case Atkins vs. Virginia, the US Supreme Court ruled that the execution of mentally retarded defendants was precluded by the Eighth Amendment's prohibition of cruel and unusual treatments, so sparing Atkins' life.

A consequence of the ruling is that convicted criminals may find themselves tempted to feign mental retardation. In the words of psychologist David Berry and colleagues, "...in cases of conviction for capital offences, [the diagnosis of mental retardation] may literally allow a defendant to escape death."

The trouble, according to Berry and colleagues, is that the literature on the ability to detect feigned mental retardation is sparse. Now these researchers have administered the WAIS-III intelligence test, two tests of psychiatric malingering, and three tests of cognitive malingering to 26 mentally retarded people and 26 non-retarded participants who had no more than 11 years of education.

Half the non-retarded participants were given information about mental retardation and asked to fake being retarded, with a reward of $20 if they managed to do so successfully.

Faking mental retardation wasn't difficult. According to the WAIS-III, even using special indices designed to detect deliberate poor performance, the scores of the non-retarded fakers were indistinguishable from the genuinely mentally retarded. The same was true for the tests of psychiatric malingering.

However, the three tests of cognitive malingering were moderately successful at distinguishing the fakers from the genuinely mentally retarded (although some of the genuinely retarded were also classified as fakers, showing the tests lacked specificity).

An example of a test of cognitive malingering is the 'Test of Memory Malingering'. This requires participants to view 50 pictures and then say which picture in a series of pairs was among those originally viewed. Performance is known to be relatively unaffected by a broad range of neuropsychological impairments which is what makes it a useful measure of malingering.

The researchers concluded: "At present there are almost no other published data on the characteristics of individuals attempting to feign MR, making it difficult to judge how 'realistic' the present malingerers were."
_________________________________

Graue, L.O., Berry, D.T.R., Clark, J.A., Sollman, M.J., Cardi, M., Hopkins, J. & Werline, D. (2007). Identification of feigned mental retardation using the new generation of malingering detection instruments: Preliminary findings. The Clinical Neuropsychologist, 21, 929-942.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Link to further information on the detection of malingering.

Is low intelligence to blame for short life expectancy in poor countries?

People in countries with a large gap between the rich and poor have short life expectancies, not because of the economic inequality and lack of resources, but rather because they are unintelligent. That’s the controversial claim of Satoshi Kanazawa of the London School of Economics, who has used data from the UN and World Bank to look at the associations between average life expectancy, prosperity and economic inequality within over 120 countries around the world.

The economic historian Richard Wilkinson has argued that economic inequality leads to shorter life expectancy because being at the bottom of the social pile puts people under prolonged stress. But Kanazawa rejects this hypothesis. He argues his data show that once population IQ is taken into account, a country’s average life expectancy is no longer related to economic development and inequality. Indeed, he found IQ was between seven and eight times more strongly related to life-expectancy than were measures of income inequality.

Kanazawa’s theory is that what we refer to as IQ is effectively a measure of people’s ability to adapt to evolutionarily new threats and demands. Populations with a higher IQ are, he argues, better able to deal with contemporary hazards like guns, cars, sedentary lifestyles (by having the sense to exercise), and drugs and alcohol – thus living longer. And he rejects the notion that IQ is simply an indirect measure of economic wealth via improved education. Intelligence, he argues, is largely genetically determined.

To support his case further, Kanazawa also focused on 29 sub-Saharan countries which have changed little since ancient times. In these countries where modern threats are absent, Kanazawa found IQ is not related to life-expectancy whereas income inequality is.

Kanazawa’s findings come after a recent Scottish study reported a positive association between intelligence and longevity, and another study that found less obese men were more intelligent than their obese peers.

“These results point to the need for epidemiologists and health psychologists to pay closer attention to the role of general intelligence in health and longevity. General intelligence may be the key that allows individuals in evolutionarily novel contemporary society to recognise health risks and deal with them appropriately”, he concluded.
___________________________________

Kanazawa, S. (2006). Mind the gap…in intelligence: Re-examining the relationship between inequality and health. British Journal of Health Psychology, 11, 623-642.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Link to related review paper.
Link to the IQ data used by Kanazawa.

Update: After reading this Digest item, Observer journalist Denis Campbell has investigated further.

Why season of birth is related to childhood intelligence

Countless studies have found that children’s intelligence appears to be related to the time of year they were born in. Some investigators have argued this is because seasonally varying environmental factors like temperature and infections can affect brain development. But now Debbie Lawlor and colleagues have analysed data from 12,150 children born in Aberdeen between 1950 and 1956, and they’ve concluded that the effect of season of birth is almost entirely explained by the age children happen to be when they start school.

Reading ability at age 9 and arithmetic ability at age 11 were both related to season of birth (children born in late Winter or Spring performed better), but this association virtually disappeared once age at starting primary school and age relative to class peers were taken into account. That is, season of birth was only related to later intelligence because it affected the age children started school, with those who started school younger or older than the average tending to score less well on later intelligence tests.

By contrast, the outside temperature when the children were conceived, during gestation, and at their birth, had no independent association with their later intelligence.

“We have found weak season of birth effects on some aspects of childhood intelligence, which appear to be explained by differences in age at school entry and/or age relative to peers”, the researchers concluded.

However, the story isn’t entirely straightforward. The researchers predicted that children who spent less time at primary school would perform less well on subsequent intelligence tests. Instead, they found the opposite pattern. “It is possible that those who had least time in primary school but most time at home were in fact given extra tuition by their parents”, they surmised.
__________________________________

Lawlor, D.A., Clark, H., Ronalds, G. & Leon, D.A. (2006). Season of birth and childhood intelligence: Findings from the Aberdeen Children of the 1950s cohort study. British Journal of Educational Psychology, In Press. DOI: 10.1348/000709905x49700.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Clever children's brains develop differently

An investigation into the link between intelligence and brain development, rare in its use of a longitudinal methodology and large sample size, has found superior intelligence is associated with particularly dynamic developmental changes to the cortex – rapid cortical thickening during childhood, followed by a period of marked pruning during adolescence.

“’Brainy children’ are not cleverer solely by virtue of having more or less grey matter at any one age," the researchers said. "Rather, IQ is related to the dynamic properties of cortical maturation”.

Philip Shaw and colleagues at the National Institute of Mental Health in America divided 307 participants aged between 3 and 25 years into three groups – average, high and superior intelligence – based on their scores on age-appropriate IQ tests. Over half the sample had at least two brain scans, 30 per cent had three or more scans.

They found the frontal cortex of participants with ‘superior’ intelligence started off thinner than in ‘high’ and ‘average’ intelligence participants, but thickened rapidly until the age of 11 years, at which stage rapid thinning occurred. By contrast, the cortex of the high and average intelligence participants thickened more slowly until the age of about 7 or 8 years, followed by a period of less marked thinning than in the superior intelligence participants.

“The prolonged phase of prefrontal cortical gain in the most intelligent might afford an even more extended ‘critical’ period for the development of high-level cognitive cortical circuits”, the researchers said.
_________________________________
Shaw, P., Greenstein, D., Lerch, J., Clasen, L., Lenroot, R., Gogtay, N., Evans, A., Rapoport, J. & Giedd, J. (2006). Intellectual ability and cortical development in children and adolescents. Nature, 440, 676-679.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Does my head look big in this?

"From the Archives", first published in the Digest 13.10.03.

Buying hats may well prove troublesome, but having a huge head also brings a key advantage - it means you're less likely to suffer mental decline in old age.

Catherine Gale (MRC Environmental Epidemiology Unit, University of Southampton) and colleagues recruited 215 men and women aged 66-75 years, measured their head circumference (itself an indicator of brain size) and gave them two sets of intelligence tests - first at the head-measuring session and then again, three and half years later. Old records also detailed the participants' head circumference at birth.

People with bigger heads scored more highly on the intelligence tests, and were less likely to show mental decline as indicated by a lower score at the second testing session relative to the first. In fact, the bottom quartile (25 per cent) of the sample for head size were five times more likely to exhibit mental decline than the quartile with the biggest heads.

Head circumference at birth, by contrast, had no relationship with intelligence or mental decline. This has important implications, because as the authors explained, it suggests "brain development during infancy and early childhood is more important than foetal growth in determining how well cognitive abilities are preserved in old age".
__________________________________

Gale, C.R., Walton, S. & Martyn, C.N. (2003). Foetal and postnatal head growth and risk of cognitive decline in old age. Brain, 126, 2273-2278.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.

Most genes that influence maths ability also affect reading

Diagnostic labels such as dyslexia and dyscalculia tend to highlight the separateness of various mental capabilities from general intelligence. But a new study has shown that most of the genes that influence young children’s mathematics ability also influence their reading and general intelligence. According to Robert Plomin and colleagues at the Social, Genetic and Developmental Psychiatry Centre at King’s College in London, this is probably because “a great variety of non-specific abilities, such as long-term memory, working memory and attention are involved in mathematical ability as well as in reading and general intelligence”. They made their finding by testing thousands of twins, some identical with matching genes, and others non-identical, who share half each other’s genes. The twins’ mathematics ability was assessed at seven years of age via teacher reports, and their reading and general intelligence was tested over the phone.

Plomin’s team found two thirds of the genetic influence on maths ability also explained variation in reading and general intelligence, thus suggesting most of the genes that affect maths also affect reading and general intelligence. Whereas genes tended to explain the similarity of a child’s performance across these domains, environmental factors tended to explain the differences. “One direction for future research is to identify the non-shared environmental factors that are experienced differently by twins, even identical twins, even in the same classroom and that contribute to differences in children’s relative performances in mathematics and reading”, the authors said.

Non-shared environmental factors are experiences that have uniquely affected one twin but not the other, even though they have been raised and taught together. Lead researcher Yulias Kovas told The Digest such factors could include “…pre-, peri- and post-natal influences, including childhood illnesses, differential parental influence, or differential effects of curricula on children”. Kovas added that “If these non-shared environmental factors can be identified, they could lead to more individualized curricula, although much more research is necessary to clarify whether such a move towards individualization in education is necessary or practically possible”.
__________________________________

Kovas, Y., Harlaar. N., Petrill, S.A. & Plomin, R. (2005). ‘Generalist genes’ and mathematics in 7-year-old twins. Intelligence, 33, 474-489.

Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.