Chimpanzees follow the leader – new study

Published: 13 January 2015 at 10:29

Anglia Ruskin scientist examines social learning in Evolution of Human Behaviour paper

New research may explain why innovative behaviour does not usually spread through populations of chimpanzees, our closest ancestor, despite the fact that different populations appear to have different behavioural traditions.

The study by Anglia Ruskin University, Durham University and the University of St Andrews found that chimps are more likely to copy the behaviour of senior members.

However, these “alpha” chimps are less likely to display innovative behaviour compared to junior members of the group, meaning that the spread of innovation is being stifled.  The study is published in the January edition of the journal Evolution and Human Behaviour.

The researchers monitored four groups of captive chimps as they carried out a novel foraging task in which a small door could be pushed right or left to retrieve food.  The spread of foraging information between chimps was measured by recording who performed the task, what method was used, and who observed it.  

In all four groups, the direction taken by the first chimp was followed by the others on the majority of occasions (81.8%, 90.2%, 98.3% and 95.7%), showing that social learning is involved in the spread of the novel behaviour.

There was also clear evidence that low- and medium-ranked individuals were more likely than high-ranked individuals to copy the behaviour of others.  Eight out of nine low-ranked individuals and 11 of the 12 medium-ranked chimps adopted the option they had observed the most.  In contrast, high-ranked individuals are less likely to be influenced by the actions of other chimps when making their choice. 

The scientists also discovered that lower-ranking chimps are more likely to observe the “alpha” individuals of the group, apparently in order to learn from them, even though the higher-ranked chimps are less strategic in their decision-making.

Dr Will Hoppitt, Senior Lecturer in Zoology at Anglia Ruskin University, said

“Our findings may explain why innovations rarely become traditions among chimps.  Low-ranked chimps rather than senior chimps are more likely to be the innovators, but it is the less innovative senior chimps that are more likely to be copied by others.”

Dr Rachel Kendal, Senior Lecturer in Anthropology at Durham University, added

“Our results may also explain why cultural diversity between populations has been maintained.  Immigrants into a population have low rank, meaning they are unlikely to be copied and bring in behaviour from other populations, which may explain why different chimpanzee populations have different traditions.”