Not just a pretty face: adult Barbary macaques recognise photos of friends
According to new research, untrained Barbary macaques are able to differentiate between pictures of familiar and unfamiliar faces.
Scientists discovered that the monkeys were able recognise photographs of group members, and spent more time studying pictures of animals that were not part of their social circle.
The team devised a simple experiment where the macaques were presented with photographs of their group members and of unfamiliar monkeys. They monitored the response of the adult and juvenile monkeys, discovering that the adult animals quickly dismissed images of group members but spent more time looking at unfamiliar primates.
This suggested that the macaques are capable of recognising members of their own group from the photographs and discriminate more against unknown individuals.
For group-living animals like the Barbary macaques, it is crucial for survival to be able to distinguish own group members and those of other groups. In the wild, this species has been shown to act more aggressively against groups that they rarely meet, compared with less aggressive interactions with those they meet more frequently.
Interestingly, juvenile monkeys were both fascinated and puzzled by the photographs. They were frequently observed displaying greeting behaviours directed towards the images, such as lip-smacking, touching and sniffing.
The findings suggest that primates learn with age and, that in adult primates at least, the monkeys are able to memorise the faces of a large number of individuals.
The results provide evidence that experience plays a key role in the development of individual recognition and understanding.
Professor Fischer says that the team's findings are hugely important for helping in future studies of primate behaviour.
Currently, studies on recognition in primates often require the subjects to receive extended training, repeatedly exposed them to pictures and rewarding them for correctly distinguishing between stimuli. By using this method, the monkeys sometimes become accustomed to the pictures prior to the actual experiment, thereby skewing the results.
With evidence that the macaques are able to spontaneously recognise photographs, Fischer believes that scientists will no longer be restricted to working in the lab and training the monkeys when studying the cognitive behaviour of these remarkable animals.
The findings are published in the journal Animal Cognition.