To the casual observer, dominant individuals in a group of rhesus monkeys appear to be more intelligent than lower ranking troop members - they are quick learners, while subordinates seem slow to catch on. New research, however, confirms what underdogs have thought all along: the subordinates aren’t stupid, they’re just keeping a low profile.
Christine Drea and Kim Wallen of Emory University, Atlanta, presented a troop of captive monkeys with a simple task: finding food in colour-coded boxes. Blue and red boxes (containing peanuts and stones respectively) were provided when the troop was together, with dominants and subordinates free to interact. The troop was then separated into high and low ranking groups, and presented the same task but with a green and yellow colour scheme.
By switching the colours around, and watching where the monkeys tried to find food, the researchers could see how the subordinate monkeys’ learning, and performance of what they had learned, was affected by the presence of the high ranking individuals.
When the troop was reunited, and faced with the green and yellow boxes, the subordinates performed badly - even though they had had the chance to learn in a stress-free environment. When the dominants were absent, the subordinates performed well with the red and blue boxes, despite the fact that dominants were present during learning.
The researchers suggest that, though they are just as capable of learning, subordinates ‘play dumb’ when dominants are around to reduce the potential for aggression against them.
(Proceedings of the National Academy of Science, vol. 96, p12965-9)