taliation. That, at least, is the conclusion of the first study to observe the primates' reactions to inequity outside a controlled laboratory setting.Young gorillas often engage in play fights that resemble what children do in a game of tag: one youngster will run up to another and hit it, then run away. The other gorilla then gives chase and hits the first one back (see video, above).
Marina Davila-Ross of the University of Portsmouth, UK, and colleagues studied video footage of six groups of gorillas in zoos. Twenty-one juveniles – both males and females – were observed chasing one another in a total of 86 games.
They found that the gorilla that did the hitting almost always moved to run away before its victim started moving. The researchers argue that this means the hitter is expecting retaliation and has therefore learned something about acceptable social behaviour.
It was a different story, however, when the gorillas played the game more gently, grabbing each other rather than hitting. Then the "grabber" was not the first to run – perhaps because the gorillas saw the gentler act as less aggressive. "Apes use play to explore the ramifications of unfair social situations," says Davila-Ross.
