Category: Genetics

Mock jury study – will behavioral genetic evidence get defendants off the hook?

3D grunge style brain image on a DNA strands backgroundBy Christian Jarrett

Around the world, neuroscience evidence is being introduced into courtrooms at an increasing rate, including findings from behavioural genetics. Specifically, some legal teams for the defence have been allowed to argue that the defendant has a low activity version of the MAOA gene, which codes for an enzyme that regulates the levels of several neurotransmitters. In combination with experiencing child abuse or maltreatment, having this low activity gene has been linked with increased impulsivity, including aggression. Defense lawyers presumably hope that jurors will interpret this as meaning the defendant was less culpable for their violent crime. However, before now, little research has examined how jurors will treat this evidence.

For a new study in Behavioral Sciences and the Law, Natalie Gordon and Edie Greene presented 600 mock jurors (half were students, half were from the wider community) with a detailed trial summary based on a real US murder trial in which the defendant, already in jail for an earlier crime, had murdered his cell-mate. The jurors’ task was to decide whether he should face the death penalty.

Continue reading “Mock jury study – will behavioral genetic evidence get defendants off the hook?”

Better educated parents have children who are more relaxed, outgoing and explorative

GettyImages-508728647.jpg
The researchers say the association between parents’ education and children’s personality is not entirely explained by genetic inheritance

By Alex Fradera

Exactly how parents shape their children is a matter of controversy, especially since Judith Rich Harris’ book The Nurture Assumption popularised the behavioural genetics position that the “shared environment” (so-called because it’s shared by siblings) – including the family home and parents’ methods of upbringing – has scant influence on how children turn out. But the debate is far from settled, and now a team chiefly from Florida State University has investigated whether more educated parents produce offspring with particular personality characteristics. Published in the Journal of Personality and Social Psychology, the research identifies a number of personality differences that correlate with parental education, and the researchers suggest the causes of this association must be more than just genetics.

Continue reading “Better educated parents have children who are more relaxed, outgoing and explorative”

Hate sport? Maybe it’s because you have the genes that make exercise feel awful

By Christian Jarrett

Have you seen those people who come out of an exercise class with a spring in their step and self-satisfied smile on their face? They really pushed themselves this time and now they’re riding that endorphin high. To them, the ache and burn feels good. But it’s not so for everyone. Others find exercise unpleasant and unrewarding – the aches just, well, ache. Psychologists call this difference the “affective response to exercise” and in a paper in Psychology of Sport and Exercise researchers in the Netherlands report new evidence that it is to a significant degree genetically inherited.

Continue reading “Hate sport? Maybe it’s because you have the genes that make exercise feel awful”

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.”

_________________________________ ResearchBlogging.org

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.

Our free weekly email will keep you up-to-date with all the psychology research we digest: Sign up!

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.”

_________________________________ ResearchBlogging.org

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.

Our free fortnightly email will keep you up-to-date with all the psychology research we digest: Sign up!