Past laboratory experiments on chimpanzees have produced more competition than cooperation, but the authors argue this reflected experimental design. “We find that chimpanzees in these restricted settings may not have had adequate opportunities to use appropriate enforcement strategies,” they write. Without any means to punish cheaters, it is unsurprising that freeloading came to dominate over joint action.
In the experiment, however, individuals had several ways to deal with those who wanted to eat without doing their share of work. These ranged from vocalizing their dissatisfaction with a mix of whimpering and screaming, through to hitting or biting the cheat. In 8 percent of cases, a third ape intervened, usually to punish the freeloading chimp. However, possibly the most effective mechanism was partner choice. Once they worked out that acquiring fruit required teamwork, individuals approached others to be their partners, and freeloaders found themselves shunned.
Although there was an initial rise in competition as participants jockeyed for opportunities to grab the fruit, they soon decided cooperation worked better; for the second half of the experiment cheating virtually disappeared.
The results challenge claims that human cooperation is a “huge anomaly” in the animal kingdom. Evidence keeps emerging of just how common cooperation is within, and sometimes between, species for the simple reason that it works.