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Stand by me: Close friendships appear to counteract genetic vulnerability to depression in girls, but not boys
Publication of US psychiatry's updated diagnostic code has provoked renewed debate in recent weeks over the extent to which mental illness ought to be framed as a psychosocial or a biological problem. The answer of course is that it is both. A new Canadian study captures this interplay, showing how close friendships appear to mitigate the risk for girls whose genes mean they are more vulnerable than average to depression.
Mara Brendgen and her colleagues studied 294 pairs of twins aged ten years old (147 girls). Some of the twins were identical (they share the same genes), the others were non-identical (sharing just half their genes). Each twin pair was raised together in the same family.
The researchers obtained ratings of the children's signs of depression from their teachers and classmates. They also gauged their close friendships by asking each child to nominate up to three best friends in their class, and to indicate who was their very best friend. Reciprocal nominations were a sign of mutual friendship. The children also answered questions about the quality of their friendships, including whether they do fun things together or get angry with each other.
Consistent with past research, there was evidence of the role of genes in depression. That is, correlations in signs of depression were much higher between identical versus non-identical twins. If one of a pair of identical twins had signs of depression, this was taken as an indication that the second twin had genetic vulnerability for the condition. If one of a pair of non-identical twins showed signs of depression, this was also taken to mean the other twin had genetic vulnerability, but less so than in the case of identical twins.
Here's the main result. Genetic vulnerability to depression in girls was less likely to manifest if they had at least one close friend. Stated differently, the apparent protective effect of having at least one close friend was magnified in girls who were genetically vulnerable to the condition. This means that for girls there was an interplay between genetic risk and the protective effect of friendship. This was not the case for boys. Friendships did appear to protect boys from depression, but this was not related in any way to their genetic vulnerability. Perhaps, the researchers surmised, there is a gender difference because "girls tend to rely more on social relationships as a source of self-definition and self-validation, and their friendships are also characterised by greater intimacy, self-disclosure, empathy and emotional support."
Separate from any issues of genetic vulnerability, another gender difference was that boys, but not girls, showed an apparently additive protective effect against depression of having more friends. The researchers said this may be because girls more often have intimate one-on-one friendships, whereas boys are more often part of friendship groups.
Other details to emerge from the study: better quality friendships were more protective against depression (regardless of genetic vulnerability); genetic vulnerability to depression wasn't associated with the likelihood of a child having friends, but it was negatively associated with the perceived quality of their friendships.
The study has some limitations, particularly the relatively small sample size, the reliance on observer ratings of depression, and the cross-sectional design, which means a causal role for friendships cannot be assumed. It's possible that the manifestation of depression symptoms in genetically vulnerable girls leads to fewer friends, rather than more friends reducing signs of depression (note however that social support is a known mitigating factor against depression). Also, the results may be specific to this age group.
Despite these shortcomings, this is an innovative study on an important topic. Children who show signs of depression pre-adolescence are at heightened risk for having problems in their teens and beyond, so the more we understand about mitigating this risk, the better. The researchers said their results "emphasise the importance of teaching social interactional skills that promote positive relations with others to help prevent the development of depressive behaviour in children."
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Brendgen, M., Vitaro, F., Bukowski, W., Dionne, G., Tremblay, R., and Boivin, M. (2013). Can friends protect genetically vulnerable children from depression? Development and Psychopathology, 25 (02), 277-289 DOI: 10.1017/S0954579412001058
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Link feast
In case you missed them - 10 of the best psychology links from the last week:
1. How too much empathy can actually lead us to do the wrong thing - thought-provoking essay by Paul Bloom. (related research covered on the Digest).
2. Thanks to books like Daniel Kahneman's Thinking Fast and Slow and, most recently, Rolf Dobelli's The Art of Thinking Clearly, hundreds of thousands, if not millions, of people are discovering the manifold biases that muddle human judgment. So how come there hasn't been a revolution in good sense and shrewd decision making? Samuel McNerney may have the answer.
3. The Digest nearly won an award this week (hold the applause), reaching finalist position for psychology/neuroscience in the inaugural Science Seeker blogging awards. Many congratulations to all the winners, especially to Aatish Bhatia winner of the psych/neuro category; to psychologist Pete Etchells who won "best post about peer-reviewed research"; and to Virginia Hughes, who won "post of the year" for her superb story about hypersomnolence.
4. The build up to the release of US psychiatry's updated diagnostic code (DSM-5) continued this week as the BPS Division of Clinical Psychology published a statement calling for a "paradigm shift" in psychiatric diagnosis "away from an outdated disease model" towards "an approach which pays far more attention to the complex range of life experiences of people experiencing mental distress."
5. The story broke at the Observer on Sunday with an unfortunate spin that implied psychology was at war with psychiatry. Professor Sir Simon Wesseley, a psychiatrist, showed there is in fact a great deal of consensus ("Mindless psychiatry is as unhelpful as brainless psychiatry, and the psychiatrist who ignores the social environment is, well, not a psychiatrist").
6. How to spot a murderer's brain (or not).
7. Ed Yong reported on an ambitious and controversial new study of super-brainy participants that's looking to pin down the genetic influences on intelligence.
8. Do nice guys really finish last?
9. If only there were somewhere you could get an expert, no-nonsense discussion of psychology research that's been splashed all over the media ... hang on, psychologist and writer Tom Stafford has started a new column for The Conversation that does just that - first off, can a poster of staring eyes really deter bike thieves?
10. The 2013 illusion of the year has been chosen - check out the winner and runners up.
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Post compiled by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Experienced job interviewers are no better than novices at spotting lying candidates
For the penultimate round of the TV show The Apprentice, the competing entrepreneurs must face a series of interviews with a crack team of hardened executives. The implicit, believable message is that these veterans have seen all the interview tricks in the book and will spot any blaggers a mile off. However, a new study provides the reality TV show with a reality check. A team led by Marc-André Reinhard report that experienced job interviewers are in fact no better than novice interviewers at spotting when a candidate is lying.
The researchers filmed 14 volunteers telling the truth about a job they'd really had in the past and then spinning a yarn about time in a job they'd never really had. The volunteers were offered a small monetary reward to boost their motivation. These clips were then played online to 46 highly experienced interviewers (they'd conducted between 21 and 1000 real-life job interviews), 92 interviewers with some experience (they'd interviewed at least once), and 214 students who'd never before acted as a job interviewer. The participants' task was to identify the clips in which the interviewee was speaking truthfully about their work experience, and the clips in which the interviewee was fabricating.
Overall the participants achieved an accuracy rate of 52 per cent - barely above chance performance, which is consistent with a huge literature showing how poor most of us are at spotting deception. But the headline finding is that the more experienced interviewers were no better than the novice interviewers at spotting lying job candidates - the first time that this topic has been researched. Greater work seniority, having more work experience and having more subordinates at work were also unrelated to the ability to spot lying job candidates.
There was a glimmer of hope that interview lie-detection skills could be taught. Participants who reported more correct beliefs about non-verbal cues to lying (e.g. liars don't in fact fidget more) were slightly more successful at recognising which job candidates were lying (each correct belief about a non-verbal cue added 1.2 per cent more accuracy on average). Experienced and novice interviewers in the current study didn't differ in their knowledge about lying cues, which helps explain why the veterans were no better at the task. The more experienced interviewers were however more skeptical overall, tending to rate more of the clips as featuring lying.
"Our results provide the first evidence that employment interviewers may not be better at detecting deception in job interviews than lay persons," the researchers said, "although it is a judgmental context that they are very experienced with."
Although the main gist of the results is consistent with related research in other contexts - for example, studies have found police detectives are no better at spotting lies, despite their interrogation experience - this study has some serious limitations, which undermine the applicability of the findings to the real world. Above all, the study did not involve real interviews, which meant the participants were unable to interact with the interviewees in a dynamic manner.
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Reinhard, M., Scharmach, M., and Müller, P. (2013). It's not what you are, it's what you know: experience, beliefs, and the detection of deception in employment interviews Journal of Applied Social Psychology, 43 (3), 467-479 DOI: 10.1111/j.1559-1816.2013.01011.x
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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Engaging lecturers can breed overconfidence
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Do fluent presenters make
learning feel too easy? |
Eloquent and engaging scientific communicators in the mould of physicist Brian Cox make learning seem fun and easy. So much so that a new study says they risk breeding overconfidence. When a presenter is seen to handle complicated information effortlessly, students sense wrongly that they too have acquired a firm grasp of the material.
Shana Carpenter and her colleagues showed 42 undergrad students a one-minute video of a science lecture about calico cats. Half of them saw a version in which the female lecturer was confident, eloquent, made eye-contact and gestured with her hands. The other students saw a version in which the same lecturer communicated the same facts, but did so in a fumbling style, frequently checking her notes, making little eye contact and few gestures.
After watching the video, the students rated how well they thought they'd do on a test of its content ten minutes later. The students who'd seen the smooth lecturer thought they would do much better than did the students who saw the awkward lecturer, consistent with the idea that a fluent speaker breeds confidence. In fact, both groups of students fared equally well in the test. In the case of the students in the fluent lecturer condition, this wasn't as good as they'd predicted. Their greater confidence was misplaced.
A second study was similar - 70 students watched either a fluent or fumbling lecturer, but this time the students had a chance afterwards to spend as long as they wanted reviewing the script. On average, both groups of students devoted the same amount of time (perhaps out of habit). But only among the students who'd watched the fumbling lecturer was there a link between time spent on the script and subsequent performance on the test. This suggests only they used the time with the script to fill in blanks in their knowledge.
"Learning from someone else - whether it is a teacher, a peer, a tutor, or a parent - may create a kind of 'social metacognition'," the researchers said, "in which judgments are made based on the fluency with which someone else seems to be processing information. The question students should ask themselves is not whether it seemed clear when someone else explained it. The question is, 'can I explain it clearly?'".
An obvious limitation of the study is the brevity of the science lecture and the fact it was on video. It remains to be seen whether this result would replicate in a more realistic situation after a longer lecture. Also, in real life, there may be costs to a fumbling lecture style that weren't picked up in this study, such as students mind wandering and skipping class.
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Carpenter, S., Wilford, M., Kornell, N., and Mullaney, K. (2013). Appearances can be deceiving: instructor fluency increases perceptions of learning without increasing actual learning. Psychonomic Bulletin and Review DOI: 10.3758/s13423-013-0442-z
--Further reading--
Co-author on this study, Nate Kornell, wrote a guest Digest post in 2008 with study tips for students.
How fluency affects judgement, choice and processing style
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
Image: Paul Clarke Wikipedia Commons. 
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Occupational hazard - links between professions and suicide risk have changed over time
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| Suicide rates have fallen among farmers |
Among the various risk factors for suicide, psychologists have recognised for some time that a person's occupation plays an important part. Suicide rates have tended to be unusually high in professions that provide ready access to guns, drugs, or open water, such as in farming, medicine, dentistry and maritime careers.
A new analysis has examined whether this still holds true. Stephen Roberts and his colleagues accessed the UK suicide rates for dozens of occupations in 1979 to 1983 and compared these with similar data recorded between 2001 and 2005.
Consistent with the ready access theory, vets, pharmacists, dentists, doctors, and farmers were all among the top 15 occupations with the highest suicide rates back in the late 70s, early 80s. But this had all changed when looking at the more recent data. In the early noughties, none of these professions were in the top 30 occupations in terms of suicide rates. Instead, the occupations with the highest rates of suicide were largely manual, including coal miners, builders, window cleaners, plasterers and refuse collectors.
Stated differently, of 55 high-risk occupations, 14 had shown reductions in suicide rate in the noughties compared with the late seventies, and these were almost exclusively highly educated professional roles like doctors, radiographers and judges, as well as farmers, actors and authors. In contrast, five of the 55 high-risk professions showed an increased rate of suicide in the later data, and these were exclusively manual professions - coal miners, labourers, plasterers, fork-lift drivers and carpenters.
The new findings are published at a time when arguments are raging over the relative prominence that should be given to biological or social explanations of mental illness.
According to this new analysis, socio-economic forces appear to have become an increasingly major factor in occupational suicide risk. The percentage of variation in suicide rates explained by an occupation's socioeconomic grouping (e.g. managerial, trade, admin etc) almost doubled from 11.4 per cent in the early data to 20.7 per cent in the early noughties. Bear in mind these figures were from before the recession, so if anything it seems likely this trend will have intensified in more recent years.
The data also showed that suicide rates were much higher among men than women, and that among men, the most at-risk occupations tended to be manual, whereas in women they were more often (non-manual) professional.
If the pattern of these results are replicated in other European and Western countries, the researchers said this "could help in developing new suicide prevention interventions that can be targeted at specific occupational groups."
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Roberts, S., Jaremin, B., and Lloyd, K. (2013). High-risk occupations for suicide Psychological Medicine, 43 (06), 1231-1240 DOI: 10.1017/S0033291712002024
--Further reading--
More Digest reports on suicide.
Men, suicide and society - why disadvantaged men in mid-life die by suicide (Samaritans report).
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.
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volevo congratularmi con lei del bellissimo articolo da lei esposto sul rimpianto. Sono un credente e sottolineo questo per dirle che per caso sono...
