We’re all familiar with the “Big Five” model of personality, which measures the traits of conscientiousness, agreeableness, extraversion, neuroticism, and openness. But what drove the evolution of these personality domains? And how do animal personalities compare with ours? Answers to the second question can help to answer the first. And now a major new study of personality in bottlenose dolphins, published in the Journal of Comparative Psychology, has found that in some key ways, dolphin personality is like ours; in others, though, it is not.
The concept of weight bias or “fatphobia”, the social stigma around obesity, has been around for quite a while. Studies have shown that such stigma is present even among medical professionals, which negatively impacts quality of care for patients with obesity. Over the years, there have been several instances of doctors attributing medical symptoms to obesity when the symptoms were actually caused by something more serious, like a tumour.
But what about social stigma towards obese pets? Over 50% of cats and dogs in the USA are obese and, like humans, pets with obesity have a higher risk of metabolic, respiratory and other diseases. A new paper in the International Journal of Obesity examines whether the same weight bias that affects the delivery of healthcare in humans is prevalent among pet doctors as well.
Comparative psychology is the study of animal behaviour, and its psychological underpinnings. But the term wasn’t always this restrictive. Until about 1935, plant behaviour also featured in texts in the field. Now Umberto Castiello at the University of Padua argues that it’s high time that plants regained their rightful place in the study of the psychology of non-human organisms.
In a paper published in the Journal of Comparative Psychology, Castiello gathers together a selection of recent evidence that plants can communicate, remember, recognise kin, decide and even count — “all abilities that one would normally call cognitive if they were observed in animals”. Far from being hard-wired, inflexible respondents to a changing world, they can adapt to change, benefit from classical conditioning, and even come to make predictions about the future.
There’s more than an improved understanding of plants at stake, writes Castiello: “As plants should be considered cognitive agents, as such, they offer us a unique opportunity for a comparative approach, which can potentially lead us to the ‘roots’ of cognition.”
It’s been known for centuries that we experience all kinds of optical illusions, and in the past few decades, researchers have shown that some animals, including monkeys, pigeons, and dogs, do too. Now the first ever study of this kind in reptiles has found that even the bearded dragon falls for an optical illusion that we humans succumb to.
Perceptual illusions — subjective interpretations of physical information — are interesting to psychologists because they reveal important insights into how we construct our representations of the world. This new work, published in the Journal of Comparative Psychology, provides evidence that at least one reptile can be counted among the animals don’t simply passively process retinal signals, but actively interpret visual data, too.
If you want to know about the special relationship between human and canine you need only watch a dog owner slavishly feed, cuddle and clean up after her furry companion, day after day after day. But is this unique cross-species relationship also reflected at a deeper level, in the workings of the canine brain? A recent study in Learning and Behavior suggests so, finding that highly trained dogs have a dedicated neural area for processing human faces, separate from the area involved in processing the faces of other dogs.
The researchers, led by Andie Thompkins at Auburn University, say their results are of theoretical importance (in relation to the evolutionary origin of cognitive abilities) and could have practical use too, potentially paving the way to using brain scans to validate the expertise of trained dogs.
Psychologists have long studied chimps and other animals with two principal, related aims: to find out the capabilities of the animal mind, and to discover what makes us truly unique, if anything. This is a challenging field. As any pet owner knows, it’s tempting to project a human interpretation onto animal behaviour. Researchers, especially when they’ve spent many years studying the same animal, can fall victim to this very bias (you’ll see a theme of this field is the powerful, close bonds frequently formed between psychologist and animal). At the same time, though, there is also a temptation to overestimate our human uniqueness. Which emotions and capabilities are exclusively human? Tool use, perspective taking and deceit were once contenders, but no more, and the list is getting shorter all the time.
This Digest feature post is a celebration of the contribution that animals have made to psychology, including eight that we’ve come to know on first-name terms:
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.
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.
In the early 1950s, while investigating rabbits’ sense of smell by recording the activity of their brain cells, the scientist Lord Adrian noticed something curious. As his team mixed up odours of increasing strength, to see at what point the rabbits’ neurons fired in response, they found the critical threshold appeared around the same point that they were able to smell the odour themselves: in other words, this suggested that the smell had become noticeable to animal and man at the same time.
On publication of the research, Lord Adrian mentioned his observation, but it didn’t provoke a serious response, presumably because informed scientists knew that the human sense of smell is generally pathetic. Everyone knew… but they knew wrong. In a new review in Science, John McGann, who runs the Rutgers Laboratory on the Neurobiology of Sensory Cognition, takes us through the historical misunderstandings to reach the truth about what the human nose knows.