It used to be easy to separate man from beast. Then we realised animals, too, can experience sophisticated emotions and communicate through language. But there is one thing that is beyond even our closest relatives, chimpanzees, and that鈥檚 the ability to be spiteful.
in Leipzig, Germany, conducted experiments in which they placed a food-laden table in front of a caged chimp. Attached to the table was a string the chimp could pull to collapse the table. The chimp resisted the urge to pull the string as long as the food was within its reach. When the researchers moved the food to the opposite side of the table, the frustrated chimp collapsed the table in 30 per cent of the trials.
In another experiment, the researchers placed a second chimp in a cage at the opposite side of the table. Moving the food across the table now benefited the second chimp at the cost of the first. If the first one wanted to be spiteful, it could simply collapse the table and prevent its rival from feeding. The chimps tested merely showed the same frustration as before, collapsing the table 30 per cent of the time. If the second chimp tried to move the food closer, by pulling a string of its own, the first chimp reacted angrily, collapsing the table 50 per cent of the time (Proceedings of the National Academy of Sciences, ).
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Spite is a common human reaction, says Jensen. 鈥淚magine you鈥檙e a kid at a birthday party. The mother gives you cake, then takes it away and gives it to another kid. It鈥檚 not his fault, but you鈥檒l still be annoyed with him because of his good fortune. But chimps don鈥檛 care who鈥檚 got the cake, just who took it from them,鈥� he explains. In other words, chimps fail to see things from another鈥檚 point of view.
鈥淐himps don鈥檛 care who鈥檚 got the cake, just who took it from them. They fail to see things from another point of view鈥�
If a chimp鈥檚 lack of empathy leaves it unable to feel spite, it may be unable to be altruistic, too, says behavioural ecologist Rufus Johnstone of the University of Cambridge. 鈥淭here have been experiments that gave chimps the chance to be nice to another at no cost to themselves, but they weren鈥檛 interested. They didn鈥檛 have a human propensity to be nice,鈥� he says.
鈥淭his is where things get tricky,鈥� admits Jensen. 鈥淥ther papers coming out of our research group show chimps are altruistic. One interpretation is that one set of researchers isn鈥檛 doing their job properly, but we don鈥檛 like that one! Maybe [altruistic] tendencies operate in a narrow range in chimps, and a broader range in humans.鈥�
In showing that chimps lack spite, the team may also have shown that a set of connected emotions remains unique to humans. 鈥淢any differences obviously remain,鈥� says Jensen. 鈥淗umans actually care about outcomes affecting others. The good side of that is altruism. Spite is the evil twin that can鈥檛 be separated from it.鈥�
