Category: biological

Nature vs Nurture: Mothers with multiple children have an intuitive grasp of behavioural genetics

 

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Lower scores equals more accurate estimates of genetic inheritance. From Willoughby et al 2018

By Christian Jarrett

Several prominent psychologists have recently raised concerns that the “radical left” has a stranglehold on free speech and thought in our universities. The psychologists argue this includes biological denialism: claims that differences between individuals and groups are entirely the result of the biased system or mere social constructions. More generally, many commentators are horrified by the apparent resurgence of far-right ideologies and their twisted interpretation of genetic science.

It’s timely, then, that a team of researchers, led by psychologist Emily Willoughby at the University of Minnesota Twin Cities, recently surveyed over 1000 online US participants, asking them about their personal circumstances, education, political orientation, and also to estimate the relative contribution of genes and the environment to variation in 21 different human traits, from eye colour to intelligence. This is probably the most detailed study to date of people’s insights into behavioural genetics, and the findings have just been published as a pre-print at the Open Science Framework.

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Men with higher testosterone levels are less into classical music and opera

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Salivary testosterone was inversely correlated with preference for “sophisticated” music in men but not women (via Doi et al, 2018)

By Christian Jarrett

What counts as music to one person, sounds to another like a headache. Some of the difference is explained by our personalities (for instance, more open-minded people prefer classical) and our thinking style (systematisers prefer heavy metal more than empathisers). What’s not been examined before now, according to a paper in Personality and Individual Differences, is the biological basis of our musical tastes.

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Sex differences in human brain structure are already apparent at one month of age

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Figure via Dean III et al, 2018

By Alex Fradera

On average, men and women differ psychologically in small but reliable ways, such as in personality, interests, and cognitive performance, but the basis of these differences is up for debate. Are they innate or due to how we’re socialised?

Neuroscientists look for traction on this question by studying sex differences in the brain, premised on the idea that these might contribute to the observed psychological differences. However, studying the brains of adults, or even teenagers, still leads to spinning wheels, because culturally produced differences will show up in the brain too. But how about one-month old infants, the subjects of a paper published in the journal Brain Structure and Function?  Since birth, babies at this age have spent most of their time sleeping and suckling with limited eyesight, so profound socialisation effects aren’t going to be a factor. And yet, the new findings reveal that sex differences in a number of brain areas are already apparent.

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Psilocybin (from magic mushrooms) plus meditation and spiritual training leads to lasting changes in positive traits

GettyImages-512153806.jpgBy Emma Young

“Conferences on psychedelics are popping up everywhere, like mushrooms!” said Jakobien van der Weijden, of the Psychedelic Society of the Netherlands, when I met her in Amsterdam last week. Indeed, research into the use of psychedelic (mind-altering) drugs as tools in the treatment of depression, post-traumatic stress disorder and end-of-life angst, is on the increase. Psilocybin, the active ingredient in magic mushrooms, may help to alleviate symptoms of depression by altering brain activity in key areas involved in emotional processing, for example.

Now a study in the Journal of Psychopharmacology, led by Roland Griffiths at Johns Hopkins University, has found that for mentally and physically healthy volunteers, two doses of psilocybin in conjunction with a programme of meditation and other “spiritual” practices was enough to bring about lasting, positive changes to traits including altruism, gratitude, forgiveness and feeling close to others.

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Researchers uncover a brain process that may help explain the curse of uncontrollable thoughts

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The study represents a breakthrough in bridging neurophysiology and psychology

By Alex Fradera

Distressing conditions including PTSD, depression and anxiety have something in common: a difficulty in suppressing unwanted thoughts. Negative self-judgments and re-experienced traumas directly impact mental health and make recovery harder by intruding into the new experiences that should provide distance and a mental fresh start. Understanding what’s involved in thought suppression may therefore be one key to helping people with these conditions. Now research in Nature Communications has uncovered an important new brain process that may help explain why some people struggle to control their thoughts.

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Positive parenting gets “under the skin”, showing up years later in the cortisol response

GettyImages-564565088.jpgBy Alex Fradera

Adolescence is when values and relationships are formed and things happen that leave their sticky fingerprints on the life that follows. Even, it seems, in the everyday functioning of brain systems. New research published in Developmental Science shows that when teenagers have a positive relationship with their parents, then as adults their brains and bodies respond to stress in a way that helps them better engage with the world. However, the study suggests this benefit may be denied to those raised in a rough environment, which seems to override the influence of positive parenting.

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Imagining bodily states, like feeling full, can affect our future preferences and behaviour

GettyImages-sb10069449r-003.jpgBy Emma Young

Our current bodily states influence our preferences and our behaviour much more than we usually anticipate – as anyone who has gone shopping hungry and come back with bags full of fattening food can attest. “Even when people have previous experience with a powerful visceral state, like pain, they show surprisingly little ability to vividly recall the state or to predict how it affects someone (including themselves) when they are not experiencing it,” write Janina Steinmertz at Utrecht University and her colleagues in their paper in Personality and Social Psychology Bulletin.

The good news is their research suggests we can exploit this phenomenon – we can trick ourselves into thinking we’re feeling differently, thereby influencing our preferences in ways that help us. For instance, one potentially important finding from their paper was that people who thought themselves full went on to choose smaller food portion sizes.

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“Significant loss of neurons is a normal part of ageing” and other brain cell myths

By Christian Jarrett

Basic facts about the brain are a key part of many introductory psychology courses, including information about brain cells. For instance, for years, students (and the public) have been taught that, thanks to the ageing process, the older we get, the more brain cells we lose. But as outlined in a new review in the Journal of Chemical Neuroanatomy by Christopher von Bartheld at the University of Nevada, many established facts about brain cells (like the idea we lose lots of them as we get older) have been shown by modern techniques to be misconceptions. Taken mostly from the review, here are four myths about brain cells, plus one unresolved issue.

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The bacteria in your gut might affect your vulnerability to PTSD

GettyImages-826555466.jpgBy Emma Young

After a traumatic experience, why do some people develop Post-Traumatic Stress Disorder (PTSD), while others don’t? Work to date has found evidence that various factors play a role, including a lack of social support and low levels of the neurotransmitter neuropeptide Y (due to its role in the body’s stress response). Into this mix come new findings, reported in Psychosomatic Medicine, that an individual’s complement of gut bacteria (their gut microbiome) may contribute to their vulnerability to trauma. The researchers are now investigating whether tweaking the gut microbiome could help to prevent or treat PTSD.

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Autistic boys and girls found to have “hypermasculinised” faces – supporting the Extreme Male Brain theory

By Christian Jarrett

According to the Extreme Male Brain theory of autism, there are certain cognitive and behavioural characteristics that manifest more often in men than women, on average, such as a bias for systematic rather than empathic thinking. Autism can be seen as as extreme version of that typical male profile, the theory proposes, possibly caused by prenatal exposure to higher than usual amounts of testosterone in the womb.

A related observation is that exposure to high concentrations of prenatal testosterone leads to the development of “hyper masculine” facial features. It follows that if the Extreme Male Brain theory of autism is accurate, then autistic people will have hypermasculine faces.

A new study in Scientific Reports put this logic to the test, and consistent with the Extreme Male Brain theory, found that autistic girls and boys had more masculine faces as compared with neurotypical control children.

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