Many animals, including sea lions and dogs, can accurately predict the size and strength of a potential adversary in part by listening to their vocalisations – such as the ferocity and depth of their barks or growls. People weren’t thought to be much good at doing something similar. But in previous studies, volunteers were asked to judge the absolute height and strength of another person, based on the sound of an aggressively-spoken sentence or a ‘roar’. Now in a new study, published in iScience, when participants were instead instructed to listen to recordings and judge how much stronger, or weaker, taller or shorter the vocaliser was, compared with themselves, they could do this with a high degree of accuracy.
As the researchers, led by David Reby at the University of Sussex, point out, this is potentially far more practically useful than being able to discern someone else’s absolute height or strength.
Celebrities are people famous for being famous. Have you ever given any thought to how it happens that pop-culture figures become so well-known, even when they have risen to the top upon a wave of interest for which there was not the slightest rational explanation? What is the real root cause of our lemming-like rush to keep tabs on insignificant but famous people? What leads us to share this information on social media? Why do we visit gossip portals and read tabloids, even though they’re totally worthless to us? Partial answers to these questions are given by a trio of researchers via a series of creative experiments that they’ve reported in Psychology of Popular Media Culture.
In 1914, the psychologist Leta Hollingworth’s experiments punctured holes in the prevailing idea that menstruating affects women’s intellect. But a century on, the ovulation cycle continues to interest psychologists, who today focus on how it affects sexual behaviour. A popular evolutionary psychology theory states that during fertile periods, women become more interested in men who use dominant masculine behaviour, as this signals they are likely to provide good genes for any offspring. A University of Goettingen team have now conducted the largest ever test of this idea, published as a pre-print at PsyArxiv.
You and your partner have had a tiff. Of all the things they could do to try to make up with you, what would be the most effective? A group of evolutionary psychologists recently put this question to 164 young adults. They presented them with 21 categories of reconciliatory behaviour, including giving a gift, cooking a meal and communicating better (derived from an earlier survey of 74 other young adults about ways to make up).
Men and women agreed that the most effective reconciliatory behaviour of all is communicating (for instance, by talking or texting). To varying degrees, both sexes also rated apologising, forgiving, spending time together and compromising as among the things their partner could do that would most likely heal wounds.
But some behaviours men thought would be more effective for making up than women, and these were their partner performing nice gestures (such as chores, favours and compliments), and offering sex or sexual favours. On the other hand, women thought their partner apologising or crying would be more a more effective way for their partner to make up than did the men.
Joel Wade at Bucknell University and his colleagues said these differences are in line with the predictions of evolutionary psychology, namely that thanks to sex differences in mating strategies shaped through our deep ancestral past, men are generally more concerned about opportunities for sex whereas women are more concerned about emotional commitment. The findings also complement past research, in the same vein, that’s found men are more likely to end a relationship if their partner is sexually unavailable, while women are more likely to end the relationship if their partner is emotionally distant.
“Evolutionary theory predicts a number of sex differences in mate selection, mate retention, and mate expulsion,” the researchers wrote in Evolutionary Psychological Science. “The present research expands this literature by documenting systematic differences in which actions men and women perceive as most effective in promoting conflict reconciliation within romantic relationships.”
We have a mostly impressive ability to identify people we know based on the sound of their voice, but prior research has uncovered an intriguing exception – we’re not very good at discerning identity from laughter. Now Nadine Lavan and her colleagues have published research in Evolution and Human Behavior that looks into why this might be and what it says about our evolutionary past.
One year ago today, Donald J Trump, a man with no political or military experience, defied expectations, winning the election to become the 45th president of the United States. Nearly 63 million voted for him, including, and in spite of his reputation for sexism, over half of all white women. In an open-access paper in Evolutionary Studies in Imaginative Culture, Dan McAdams, one of the world’s leading experts in personality psychology, proposes an explanation for Trump’s popular appeal that is grounded in evolutionary psychology, personality theory and the social psychology of leadership.
There are behavioural differences, on average, between the sexes – few would dispute that. Where the debate rages is over how much these differences are the result of social pressures versus being rooted in our biology (the answer often is that there is a complex interaction between the two).
For example, when differences are observed between girls and boys, such as in preferences for play, one possibility is that this is partly or wholly because of the contrasting ways that girls and boys are influenced by their peers, parents and other adults (because of the ideas they have about how the sexes ought to behave). Studying non-human primates allows us to identity sex differences in behavior that can’t be due to human culture and gender beliefs.
Learning more about the biological roots of behavioural sex differences should not be used as an excuse for harmful stereotyping or discrimination, but it can help us better understand our human nature and the part that evolved sex differences play in some of the most important issues that affect our lives, including around diversity, relationships, mental health, crime and education.
“Many sex differences in behavioral development exist in nonhuman primates,” she writes, “despite a comparative lack of sex-biased treatment by mothers and other social partners”. Here is a digested account of five of these behavioural sex differences:
Conscientiousness is a fundamental aspect of human personality, with higher levels associated with all kinds of benefits, from greater academic achievement and relationship stability to living for longer. Yet it’s the only major human personality dimension not to have been widely identified in animals, which poses an evolutionary puzzle – if animals don’t show signs of conscientiousness, where did the human variety come from? But now a major review of hundreds of relevant papers, published in Psychological Bulletin, concludes that in fact, “there are many documented examples of conscientiousness behaviour in other animals”. The work also suggests that there are two main branches to conscientiousness, each associated with an evolutionary drive to solve different types of problems.
While the idea that the lack of women in science and tech is entirely about cultural obstacles is contentious (as demonstratedby the recent Google memo furore), few would argue that social and cultural factors aren’t important. And these social influences may begin early. For example there’s an argument that boys are encouraged to play with toys that are likely to promote skills that will help them in science and maths. Toys aimed at girls, in contrast, are more likely to promote stereotypically feminine skills, such as nurturing.
LEGO, say Megan Fulcher and Amy Hayes, the authors of a new paper in the journal Sex Roles, is a case in point: its marketing is skewed towards boys, especially since the increase in packaged sets, which tend to feature stereotypically masculine items like pirate ships and castles. The result, they argue, is that boys are more attracted to LEGO, girls deterred from it, and that boys get to practice their building skills while girls don’t.
LEGO has heard some of this criticism (and no doubt also seen a gap in the market) and they’ve released girl-friendly packaged sets and product lines, including Friends items with a focus on people and including pink bricks. But Fulcher and Hayes – who very much speak from the nurture perspective on these issues (they fail to cite a single study demonstrating a biological basis for sex differences in toy preference) – fear this could be counterproductive because girlie bricks and sets are likely to promote more stereotypically feminine LEGO play and remind girls of their gender. To find out if their concerns are justified the researchers tested the LEGO building skills and choices of 116 girls and boys (aged 5 to 10) depending on whether they were given boyish LEGO bricks and packages or girlie ones.
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 traitsin chimps, which could lead to a better understanding of the traits in people.