As humans get older, they become increasingly selective in terms of how they spend their time and with whom. However, it turns out we’re not the only ones who do that, as researchers note a similar behavior in aging Barbary macaques.
Published in the journal Current Biology, a new research has found this type of selective attitude-behavior in monkeys in an enclosure, for which they conducted behavioral and experimental studies.
While focusing on this particular species of monkeys, the team hoped to find an explanation for the very similar human behavior that occurs as they age.
According to leading researcher, Laura Almeling of the German Primate Center in Göttingen, Germany, previous theories stated that humans reduce their social circle as they age because they want to cherish the limited time remaining and spend it only with loved ones.
But this hypothesis cannot be applied to macaques, as they have no knowledge of their limited time as they age. Therefore, the increased selectivity might be caused by certain psychological changes.
For the experiments, the team devised various scenarios that would help them determine the Barbary macaques’ social and environmental selectivity at different ages. The sample of more than 100 monkeys was kept in an enclosure where the researchers placed different objects.
Younger animals showed higher interest in new animal toys or treats, while the adult macaques were pretty “meh” when it came to playing with them. A food tube was also placed in their enclosure and it was the only object that was interesting enough for all age groups.
Gauging their curiosity was only one of the experiments. The team was also curious how the monkeys interacted with each other after seeing pictures of newborn macaques and after hearing recordings of “friends” screaming for help.
Older female monkeys were the pickiest in terms of whom they interacted with, even when other members of the community were interested in engaging and maintaining relationships with them.
“With increasing age, the monkeys became more selective in their social interactions,” noted Dr. Almeling. “Interestingly, however, they were still interested in what was going on in their social world.”
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