Category: Genetics

Researchers are studying psychopathic chimps to better understand the human variety

GettyImages-584864828.jpgBy Emma Young

To understand the drivers of a psychopathic personality (marked by callousness, disinhibition and superficial charm), it’s worth looking at our closest relatives. Some chimps, like some people, score highly on scales designed to evaluate psychopathic tendencies. And new work in Frontiers in Neuroscience reveals a potentially important genetic contributor to psychopathic traits in chimps, which could lead to a better understanding of the traits in people.

Continue reading “Researchers are studying psychopathic chimps to better understand the human variety”

Is creativity something you inherit from your parents?

6930271257_36904725a1_bBy Alex Fradera

Jeb Bush’s failure to secure a Presidential triple-play is memorable perhaps because it’s an exception to a familiar routine: the family dynasty. It’s a routine especially common in the arts, where a writer’s family tree is apt to contain a couple of actors, a director, and maybe a flower arranger to boot. This might simply reflect upbringing – or maybe the powers of nepotism – but creative success also owes to temperament and talents, some of which may have their origins in our genetic makeup. The journal Behavioural Genetics has recently published a heritability study that explores how deeply a creative vocation sits in our DNA.

Continue reading “Is creativity something you inherit from your parents?”

Many of the same genes that influence our personality also affect our mental health

Prototype of womenBy Christian Jarrett

We know from twin and family studies that our personality is to a large degree – probably around 40 per cent – inherited. Geneticists are busy trying to find the specific gene variants involved, but because each one on its own only exerts a modest influence, this is challenging research requiring huge samples. A new study in Nature Genetics has made a significant contribution, using the technique of Genome Wide Analysis to look for genetic variants that correlate with personality. The researchers led by Min-Tzu Lo at the University of California, San Diego have identified variations in six genetic loci that correlate with different personality trait scores, five of which were previously unknown. In a separate analysis, the researchers also showed that many of the genetic variants involved in personality overlap with those involved in the risk of developing mental health disorders.

Continue reading “Many of the same genes that influence our personality also affect our mental health”

Some children are extra sensitive to parenting style, bad and good

By Christian Jarrett

Just over ten years ago, a fascinating journal article argued that some children are like orchids – they don’t just wither in response to a harsh upbringing, they also flourish in a positive environment, unlike their “dandelion” peers who are less affected either way. Since then, research into this concept has exploded. A new meta-analysis in Psychological Bulletin usefully gathers all that we know so far about one key aspect of this – the associations between children’s temperament (the forerunner to adult personality) and the way they respond to different parenting styles. The results suggest that those with a particular kind of highly emotional temperament are more likely to match the description of an orchid child*. Continue reading “Some children are extra sensitive to parenting style, bad and good”

It’s now possible, in theory, to predict life success from a genetic test at birth

one week old newborn girl on daddy's hand.By guest blogger Stuart Ritchie

For decades, we’ve known from twin studies that psychological traits like intelligence and personality are influenced by genes. That’s why identical twins (who share all their genes) are not just more physically similar to each other than non-identical twins (who share half their genes), but also more similar in terms of their psychological traits. But what twin studies can’t tell us is which particular genes are involved. Frustratingly, this has always left an ‘in’ for the incorrigible critics of twin studies: they’ve been able to say “you’re telling me these traits are genetic, but you can’t tell me any of the specific genes!” But not any more. Continue reading “It’s now possible, in theory, to predict life success from a genetic test at birth”

Genetic research can promote peace or conflict, depending on how it’s used

It’s becoming easier than ever to research the genetic roots of different ethnic groups and these findings can be framed differently to either emphasise that groups are similar or different. For example, a BBC headline from 2000 stated “Jews and Arabs are ‘genetic brothers’” while a 2013 Medical Daily headline claimed “Genes of most Ashkenazi Jews trace back to indigenous Europe, not Middle East“. As political leaders have started citing this kind of evidence to promote their particular agenda, be that to unite or divide peoples, a new study in Personality and Social Psychology Bulletin has investigated whether genetic information could be a tool for promoting peace or a weapon to stir conflict.

Sasha Kimel and her colleagues began by asking 123 Jewish and 57 Arab participants in the US to read either the BBC “genetic siblings” article from 2000 or an adapted “genetic strangers” version which reversed the findings to suggest that Arabs and Jews are genetically very dissimilar. The participants had no idea that they’d been recruited based on their ethnicity, and to further disguise the aims of the research they were told that they would be tested on their memory of the article after completing a series of distracting psychological tests. In reality, some of these tests were used to reveal any effects of the articles on the participants’ attitudes and this included a measure of their views of a typical Arab- or Jewish-American and a test of their implicit (subconscious) attitudes towards Arabs and Jews.

As the researchers expected, Jews and Arabs rated each other more positively after reading about their genetic similarities compared with reading about their differences, although there were no effects on implicit attitudes.

A second study was similar but involved Jewish participants only, and this time the researchers showed that reading about genetic similarities between Jews and Arabs led the participants to display less aggression towards an Arab opponent called Mohammed in a reaction time contest. That is, on winning trials, the Jewish participants had the chance to blast their Arab opponent with white noise, and those participants who’d read about genetic similarities chose weaker noise blasts than those who’d read about genetic differences.

A third study with more Jewish participants was also similar but added a third baseline neutral condition in which participants read an article that had nothing to do with genetics or ethnic groups. This time the main outcome measure was support for Israeli peacekeeping. These results suggested that the “genetics strangers” article wasn’t having much influence on participants compared with the neutral condition, but that the “genetic siblings” article was boosting support for peacekeeping via its effect of improving attitudes towards Arabs.

Based on these initial results the researchers said that they “encourage interventions that create greater awareness of the considerable amount of genetic overlap that exists between all of the world’s ethnic and racial groups”.

But would these benefits translate to Israel, a nation that lives with ongoing interethnic conflict? The fourth and arguably most important study tested the effects of the same three news articles (“genetic siblings”, “genetic strangers” and a neutral story) translated into Hebrew and adapted so they appeared to have been published in the Israeli newspaper Ynet. The researchers recruited nearly 200 Jewish Israeli’s on commuter trains in North and South Israel and had them read one of these three stories before completing tests of their attitudes towards Palestinians and their support for different policies. The worrying finding this time was that the “genetic siblings” article appeared to have no benefit, but that the “genetic strangers” article reduced support for peaceful policies via increasing antipathy towards Palestinians.

Based on their last study, the researchers warned that “…learning about how you are genetically different from an enemy group may have a particularly menacing effect in the contexts of war”. They added: “Based on our findings, we suggest that crisis-monitoring organisations (e.g. International Crisis Group, Genocide Watch) go on heightened alert when conflict-rhetoric begins emphasising genetic differences.”


Kimel, S., Huesmann, R., Kunst, J., & Halperin, E. (2016). Living in a Genetic World: How Learning About Interethnic Genetic Similarities and Differences Affects Peace and Conflict Personality and Social Psychology Bulletin, 42 (5), 688-700 DOI: 10.1177/0146167216642196

–further reading–
Could lessons in genetic variation help reduce racial prejudice?

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

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Twin study raises doubts about the relevance of "grit" to children’s school performance

Grit is in vogue. US psychologist Angela Duckworth’s TED talk on grit is one of the most popular recorded. And her forthcoming book on the subject, subtitled “the power of passion and perseverance” is anticipated to be a bestseller. On both sides of the pond, our governments have made the training of grit in schools a priority.

To psychologists, “grit” describes how much perseverance someone shows towards their long-term goals, and how much consistent passion they have for them. It’s seen as a “sub-trait” that’s very strongly related to, and largely subsumed by, conscientiousness, which is known as one of the well-established “Big Five” main personality traits that make up who we are.

The reason for all the interest in grit, simply, is that there’s some evidence that people who have more grit do better in life. Moreover, it’s thought that grit is something you can develop, and probably more easily than you can increase your intelligence or other attributes.

But to a team of psychologists based in London and led by behavioural genetics expert Robert Plomin, the hype around grit is getting a little out of hand. There just isn’t that much convincing evidence yet that it tells you much about a person beyond the Big Five personality traits, nor that it can be increased through training or education.

Supporting their view, the researchers have published an analysis in the Journal of Personality and Social Psychology of the personalities, including grit, and exam performance at age 16 of thousands of pairs of twins. Some of the twins were identical meaning they share the same genes, while others were non-identical meaning they share roughly half their genes just like non-twin siblings do. By comparing similarities in personality and exam performance between these two types of twin, the researchers were able to disentangle the relative influence of genes and the environment on these measures.

The main finding is that the participants’ overall personality scores were related to about 6 per cent of the variation seen in their exam performance. Grit specifically was related to just 0.5 per cent of the differences seen in exam performance. Given the small size of this relationship, the researchers said “we believe that these results should warrant concern with the educational policy directives in the United States and the United Kingdom.”

Also relevant to the hype around grit, the researchers found that how much grit the participants had was to a large extent inherited (about a third of the difference in grit scores were explained by genetic influences), and that none of the difference in grit was explained by environmental factors that twin pairs shared, such as the way they were raised by their parents and the type of schooling they had (this leaves the remaining variance in grit either influenced by so-called “non-shared environmental factors” – those experiences in life that are unique to a person and not even shared by their twin who they live with – or unexplained). This is a disappointing result for grit enthusiasts because it suggests that the experiences in life that shape how much grit someone has are not found in the school or the home (at least not for the current sample). Bear in mind, though, that this doesn’t discount the possibility that a new effective home- or school-based intervention could be developed.

The researchers concluded that once you know a child’s main personality scores, knowing their amount of grit doesn’t seem to tell you much more about how well they’ll do at school. This study doesn’t rule out the idea that increasing children’s grit, if possible, could be beneficial, but the researchers warned that “more research is warranted into intervention and training programs before concluding that such training increases educational achievement and life outcomes.”


Rimfeld, K., Kovas, Y., Dale, P., & Plomin, R. (2016). True Grit and Genetics: Predicting Academic Achievement From Personality. Journal of Personality and Social Psychology DOI: 10.1037/pspp0000089

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

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Psychologists study twins to learn more about the roots of procrastination

With so many digital distractions a mere mouse click away, procrastination is easier than ever. You want, nay need, to work on an important project, yet find yourself browsing Twitter, making coffee, checking email – basically anything other than doing what you should be doing. Daniel Gustavson and his colleagues – the authors of a new twin study of procrastination published in the Journal of Experimental Psychology: General – sum it up as “the irrational delay of an intended course of action”.

Much has been written about why we fall prey to this habit in the moment (the all-important job is perceived as too challenging, the other tasks and distractions seem easier, and so on), but Gustavson and his colleagues wanted to learn more about why some of us are generally more prone to procrastination than others. Do we inherit a predisposition for procrastination in our genes, and what other mental abilities are related to the procrastination habit?

The researchers recruited 386 pairs of same-sex twins, 206 of whom were identical twins, meaning they have the same genes, and 179 were non-identical, meaning they share on average half their genes. After missing data were removed, the final sample included 401 women and 350 men (average age 23). The twins completed a questionnaire about their proclivity for procrastination (this involved rating their agreement with statements like “I am continually saying ‘I’ll do it tomorrow'”), and they answered questions about their proneness to “goal failures” (tested through questions like “Do you find you forget what you came to the shops to buy?”).

The twins also completed several measures of their “executive function”, including their powers of inhibition (e.g. one task involved resisting the reflex to glance at a square that appeared on-screen, and looking instead in the opposite direction), their ability to shift mind-sets (e.g. categorising shapes on a coloured background by their shape one minute, then by their colour, depending on changing task instructions), and their ability to juggle information in memory over short periods of time.

By comparing similarities in executive function performance, procrastination proneness and goal failures between identical and non-identical twins, the researchers were able to deduce how much of an influence genes have on these traits and abilities, and how much overlap there is in the genetic influence on the different measures. In simple terms, a higher correlation on a particular measure among identical twins compared with non-identical twins would indicate a greater role for genes.

Here are some of the key findings. The tendency to procrastinate was found to be partly inherited – 28 per cent of variability in this trait was explained by genetic influences (though note, this includes gene-environment interactions, such as a procrastinator choosing a job – like being a blog editor – that makes procrastination easier). Moreover, 17 per cent of the procrastination variability that was explained by genes overlapped with the genetic influences on goal failures – that is, many of the same genes influencing procrastination appear to play a role in the ability to manage goals. Also, environmental influences common to both procrastination and goal management explained a further 28 per cent of variation in procrastination.

The tendency to procrastinate also correlated with overall executive function ability – that is, people who said they procrastinated more tended to achieve an overall poorer score on the executive function tests. And again there was genetic overlap: many of the genetic influences on executive function were found to be the same as those shared by both procrastination and goal management.

There was one caveat in the association between procrastination proneness and executive function. Procrastinators actually tended to perform better on the ability to shift mind-sets, presumably because having a butterfly mind gives you a certain mental flexibility even though it makes it difficult to focus.

The findings help to pick apart the root causes of procrastination. At a genetic and behavioural level, they show that a tendency to procrastinate tends to go hand in hand with an ability to manage goals, and mostly a poorer ability to control one’s own mind, in terms of inhibition and juggling information.

Gustavson and his team warned that identifying the actual genes involved in procrastination, executive function and goal management remains a long way of, and that many hundreds or thousands of gene variants are likely involved. They also cautioned that their study can’t tell us about the causal relationships, if any, between the studied traits – it’s tempting to assume that poor executive function or goal management causes procrastination, for example, but it’s theoretically possible the influence could run the other way, both ways, and/or that other factors not studied here are more relevant, such as personality or intelligence. Nonetheless, the researchers did offer some brief practical advice on the back of their findings:

“Training subjects on how to set good goals may improve their ability to manage these goals and avoid procrastination … Moreover, helping subjects retrieve their important long-term goals and use those goals to avoid getting side-tracked by short-term temptations (e.g. developing implementation intentions) might also be effective at reducing procrastination.”


Gustavson, D., Miyake, A., Hewitt, J., & Friedman, N. (2015). Understanding the Cognitive and Genetic Underpinnings of Procrastination: Evidence for Shared Genetic Influences With Goal Management and Executive Function Abilities. Journal of Experimental Psychology: General DOI: 10.1037/xge0000110

–further reading–
The cure for procrastination? Forgive yourself!
Psychologists investigate a major, ignored reason for our lack of sleep – bedtime procrastination
Forgive yourself for relaxing in front of the TV and the couch time might actually do you some good

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

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New genetic evidence suggests face recognition is a very special human skill

Example stimuli from Shakeshift and Plomin, 2015.

A new twin study, published today in PNAS, of the genetic influences on face recognition ability, supports the idea that face recognition is a special skill that’s evolved quite separately from other aspects of human cognition. In short, face recognition seems to be influenced by genes that are mostly different from the genes that influence general intelligence and other forms of visual expertise.

The background to this is that, for some time, psychologists studying the genetics of mental abilities have noticed a clear pattern: people’s abilities in one domain, such as reading, typically correlate with their abilities in other domains, such as numeracy. This seems to be because a person’s domain-specific abilities are strongly associated with their overall general intelligence and the same genes that underlie this basic mental fitness are also exerting an influence on various specific skills.

Nicholas Shakeshaft and Robert Plomin were interested to see if this same pattern would apply to people’s face recognition abilities. Would they too correlate with general intelligence and share the same or similar genetic influences?

The researchers recruited 2,149 participants, including 375 pairs of identical twins who share the same genes, and 549 non-identical twins, who share roughly half the same genes, just like typical siblings (overall the sample was 58 per cent female with an average age of 19.5 years). The participants completed a test of their face processing skills, including memorising unfamiliar faces, and also tests of their ability to memorise cars, and their general intelligence, in terms of their vocabulary size and their ability to solve abstract problems.

Comparing the similarities in performance on these different tests between identical and non-identical twin pairs allowed the researchers to estimate how much the different skills on test were influenced by the same or different genes.

All the abilities – face recognition, car recognition and general mental ability – showed evidence of strong heritability (being influenced by genetic inheritance), with 61 per cent, 56 per cent, and 48 per cent of performance variability in the current sample being explained by genes, respectively.

Crucially, performance on face recognition was only moderately correlated with car recognition ability (r = .29 where 1 would be a perfect correlation) and modestly correlated with general mental ability (r = .15), and only 10 per cent of the genetic influence on face recognition ability was the same as the genetic influence on general mental ability (and likewise, only 10 per cent of the genetic influence on face memory was shared with the genes affecting memory for cars).

Essentially, this means that most of the genetic influences on face recognition ability are distinct from the genetic influences on general mental ability or on car recognition ability. Shakeshaft and Plomin said this “striking finding” supports the notion that there is something special about human facial recognition ability. These results add to others that have suggested face recognition is a special mental ability – for instance, some have argued that faces alone trigger brain activity in the so-called “fusiform face area” (although this claim has been challenged); and unlike our ability to recognise other objects or patterns, our ability to recognise faces is particularly impaired when faces are inverted, consistent with the idea that we use a distinctive “holistic” processing style for faces.

The story is complicated somewhat by the researchers’ unexpected finding that recognition ability for cars was also linked with distinct genetic influences that mostly did not overlap with the genetic influences on general mental ability. Perhaps, the researchers surmised, the tests of general mental ability used here (a vocab test and the well-used Raven’s Progressive Matrices) did not adequately tap the full range of what we might consider general mental abilities. Whatever the reason, it remains the case that this new research suggests that face recognition ability is influenced by a set of genetic influences that are largely distinct from those implicated in a similar form of visual recognition (for cars) and implicated in vocab ability and abstract reasoning. Based on this, the researchers concluded they’d shown for the first time that “the genetic influences on face recognition are almost entirely unique.”


Nicholas G. Shakeshaft, & Robert Plomin (2015). Genetic specificity of face recognition PNAS

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

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Why do more intelligent people live longer?

227a6-senior2bchessBy guest blogger Stuart Ritchie

It’s always gratifying, as a psychologist, to feel like you’re studying something important. So you can imagine the excitement when it was discovered that intelligence predicts life expectancy. This finding is now supported by a large literature including systematic reviews, the most recent of which estimated that a difference of one standard deviation in childhood or youth intelligence (that’s 15 IQ points on a standardised scale) is linked to a 24 per cent lower mortality risk in the subsequent decades of life. That’s a pretty impressive link, but it immediately raises a critical question: why do brighter people live longer?

A new study (pdf) published in the International Journal of Epidemiology attempts to provide new, biological evidence to answer this question. But first, let’s think through the possibilities. We know that people with higher IQ scores tend to be healthier, possibly because they eat better, exercise more, are better able to understand health advice, are less likely to be injured in accidents and deliberate violence, and also because they tend to have better jobs. Here, the causal arrow is pointing from IQ to longevity – the effects of being smarter cause you to die later. But there are other explanations: what if having a lower IQ is just an indicator of an underlying health condition that’s the real cause of earlier death? Or what if the genes for having a healthier body are also the genes for having a healthier brain, and the causal pathway is from this third variable (i.e. genetics) to both IQ and longevity?

The authors of the new study, Rosalind Arden and colleagues, tested this last hypothesis, known as “genetic pleiotropy” (the idea that the same genes influence multiple different traits). They took three twin datasets, selecting in total 1,312 twin pairs where one or both of the twins had died. Then they correlated the twins’ IQ scores with the lengths of their lives (or their life expectancies, for those still living).

As they expected, the researchers found an overall lifespan-IQ correlation, albeit a small one (r = 0.12, where 1.00 would be a perfect match). Importantly, by comparing the correlations in identical twins (who share all their genes) versus fraternal twins (who share approximately half), they were also able to estimate the “genetic correlation” – the overlap in the two traits that’s caused by genetic differences. They found that, overall, 95 per cent of the correlation in IQ and longevity was due to genetics.

So, is this a final answer to the debate over the IQ-mortality connection? Does this show that, perhaps depressingly, the link isn’t due to changeable lifestyle factors, but actually some kind of genetic “system integrity” that underlies brightness and longer lives?

Ritchie’s critically acclaimed
new book is out now.

Not so fast. The important part is in the phrase “due to genetics”. In a 2013 Nature Reviews Genetics article, geneticist Nadia Solovieff and colleagues outlined all the potential causal mechanisms that might make two traits genetically correlated. They drew a critical distinction between “biological” and “mediated” pleiotropy. The former is the “obvious” inference, which is that the same genes cause both intelligence and longevity. But the latter possibility is that the variables only appear to be genetically correlated, because genes cause one factor, which then goes on to cause the other. That is, if genes cause intelligence, and intelligence (via lifestyle choices etc.) causes a longer lifespan, we’d still see the same genetic correlation, even if those genes have no direct effect on lifespan itself. If true, this would still be pleiotropy of a sort: the genes linked to intelligence are having an indirect effect on lifespan. But as the authors acknowledge in their paper, this “pleiotropy-lite” interpretation of the new findings would mean we don’t yet have knockdown evidence for the genetic “system integrity” idea.

So how do we tease apart the two possible explanations for the genetic correlation? In the paper, the authors suggest we study non-human animals (for which the literature on cognitive ability is growing fast) where we can more readily control the “lifestyle” factors, thereby isolating any potential direct effects of the same genes on both intelligence and longevity. Really, though, we might have to wait until we have a long list of genes that are reliably linked to human intelligence. If we knew a good number of those, we could test whether they also influence health and lifespan – if they did, this would be evidence for true “biological” pleiotropy. We’d know then that the link between IQ and lifespan is down to some people simply winning the genetic lottery, rather than to lifestyle factors that any of us could change.

Conflict of interest: Stuart Ritchie is a postdoc in the lab of Ian Deary, one of the co-authors of the paper discussed here.


Arden, R., Luciano, M., Deary, I., Reynolds, C., Pedersen, N., Plassman, B., McGue, M., Christensen, K., & Visscher, P. (2015). The association between intelligence and lifespan is mostly genetic International Journal of Epidemiology DOI: 10.1093/ije/dyv112

further reading
How do you prove that reading boosts IQ?

Post written by Stuart J. Ritchie, a Research Fellow in the Centre for Cognitive Ageing and Cognitive Epidemiology at the University of Edinburgh. His new book, Intelligence: All That Matters, is available now. Follow him on Twitter: @StuartJRitchie

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