Fast-learning lemurs hold the key to popularity

What do you look for in a mate? Humour, warmth, empathy, compassion? Pah. It’s all about the capacity to retrieve grapes from a Plexiglas box, if the world’s lemur population is anything to go by.

The furry primates have proved enormously illuminating in the relationship between learning and social standing. Previously, the latter was acknowledged to influence the former: those who were more centrally socially positioned were more likely to solve a given task. But a recent study published in Current Biology has discerned that the capacity for learning and problem-solving, when witnessed by fellow primates, can actually bolster lemurs’ social centrality.

“We found that lemurs who were frequently observed by others while solving the task to retrieve the food received more affiliative behaviors than they did before they learned,” explains Ipek Kulahci, a postdoctoral researcher at Ireland’s University College Cork (formerly of Princeton University). “As a result, they became more socially central than they were before the experiment.”

The Princeton team observed two sets of free-ranging ring-tailed lemurs (comprising around 20 individuals each) on St Catherine’s Island on the coast of Georgia in the US. Observers charted the lemurs’ interactions whilst navigating the aforementioned fruit-containing Plexiglas box, with striking results. Whilst lemurs who were initially more centrally socially positioned were more likely to solve the task at hand (retrieving those pesky grapes), the reverse also proved to be true: lemurs who extracted the grapes to an audience of peers became more popular with those onlookers.

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But how does one measure the social prowess of a lemur, I hear you asking. “Affiliative behaviours,” such as grooming, are indicative of popularity in a conspiracy of lemurs (yes, that’s the correct terminology for a whole bunch of them). This surprises Kulahci: “I was quite impressed that the frequently observed lemurs received more affiliative behaviours […] without adjusting their own behaviours.” This kind of attentiveness, she explains, is normally reciprocal among primates. But visibly capable lemurs attracted the kind of one-sided grooming usually reserved for dominant individuals – a status to which fast-learners are thenceforth propelled. The dynamic, as such, is a cyclical one.

The study’s findings provide a fascinating insight into the complexity and nuance of animal behaviour. Rather than learn solely about physical environment, seeking out food in alien situations, lemurs suss out each other, storing information to make prudent decisions when forming social relationships. “They are learning about who is successful and who is not and adjusting their social responses based on this information. Being socially connected to successful individuals increases opportunities to learn from and copy them and improves future success,” explains Kulahci. It is exactly this savviness which leads fast-learning lemurs to amass ‘friends’, in turn ameliorating their cognitive capability: “The diversity and the strength of their social relationships, in turn, influence if and when they learn from their group members.” There you have it: cognitive ability and social behaviour in lemurs are inextricably bound.

So next time you’re attempting to bolster your social life, why not make like a conspiracy of lemurs with a flamboyant display of cognitive ability? It might not have worked as a Year Seven swot, but there’s a whole history of evolution that attests otherwise – at least as far as grape collecting is concerned.