Like humans, monkeys have the ability to use tools, display complex social behavior, and learn new things. Various personalities can also be observed in the primates. Biologists have now used marmosets to study the role that personality plays in the monkeys’ ability to learn and how this is influenced by their family background. Their study reveals: brave learns faster.
Along with some birds, monkeys are among the smartest and most trainable groups in the animal kingdom. Their cognitive abilities allow them, in part, to develop behaviors and skills that have long been considered the domain of humans. However, there are large differences in the ability to learn, both between different species and between individuals within a species. However, while such intraspecific differences in the ability to learn and pay attention in humans have been well studied, the causes for them in non-human species have only been partially elucidated so far.
Brave monkeys, shy monkeys
Vedrana Šlipogor from the University of Vienna and her colleagues have now examined a possible explanation in more detail. “One of the possible reasons is the intraspecies differences in behavior, which are influenced by both physical and social environmental factors,” the researchers write. Thus, an animal’s personality could influence how well it can learn new things, for example. For a long time it was assumed that only humans have personalities. In recent decades, however, scientists have shown that animals – from spiders to monkeys – can also have individual personality traits. They express themselves, among other things, in how fearful, courageous or open to new things an individual is.
To test this hypothesis, the research team looked at common marmosets (Callithrix jacchus), a species of New World monkeys that live together in social groups and resemble humans in some respects in their cooperative and social traits. Typically, a family group of these monkeys consists of a reproductive pair and their adult offspring. For their experiment, Šlipogor and her colleagues first observed 25 common marmosets from five different families living in the monkey enclosure of the University of Vienna in order to obtain information about their personalities. To do this, they recorded, among other things, how the individual animals react to new or strange objects and new food or how long it takes before they approach a toy snake.
Brave learns faster
Indeed, these observations revealed personality differences between the monkeys: some of the monkeys were adventurous and courageous, while others tended to avoid new stimuli and stay away. After the researchers were able to better assess the monkeys’ characters, they tested their learning performance using tasks of varying difficulty. For example, the animals had to learn the difference between two objects and associate one of them with a subsequent reward, or stand on a scale and hold an object for a long time, which was also rewarded with food.
These results of these learning experiments suggest that learning ability is indeed related to the personality and social background of the monkeys. For example, the females learned much faster than male common marmosets. Above all, however, it was noticeable that courageous and fearless monkeys mastered the various learning tasks much faster than the animals, to which the researchers attributed shyness and reserve. These differences were also related to family membership. On average, those monkey families that were made up of rather shy members performed worse on the tasks, as the researchers report.
Interplay of personality and cognition
“It seems that both the personality traits and the social environment determine the individual cognitive abilities of marmosets,” says Šlipogor. The fact that belonging to a certain family group influences the pace of learning could possibly be due to the shared social environment, shared previous experiences, but also to genetics. According to the biologists, the discovered connection is also plausible with regard to evolutionary processes. Because bold and adventurous animals often conquer new habitats where they have to face new challenges. Because animals with higher cognitive abilities are more likely to survive, natural selection favors both brave and clever individuals.
“In our next studies, we want to find out whether these results can also be confirmed by other tasks that are perhaps a little more cognitively challenging, and whether this effect also occurs in other highly social animals with similar socio-ecological characteristics,” says Šlipogor.
Source: University of Vienna; Specialist articles: Scientific Reports, doi: 10.1038/s41598-022-10296-8