Great Apes May Occasionally Engage in Reciprocal Food Exchange Under the Right Conditions

A new study by psychologists from Israel, UK and USA has revealed that great apes, such as chimpanzees and bonobos, can engage in reciprocal food exchange under certain conditions.

The study, published in the journal Proceedings of the Royal Society B, suggests that apes have the cognitive and social skills to cooperate and reciprocate with others when it benefits them.

The experiment: testing apes' willingness to share food

(Photo : JACK GUEZ/AFP via Getty Images)

The researchers conducted treat-giving experiments with captive chimpanzees and bonobos at two different sites, as per Phys.org.

Two apes were situated in adjoining cages with an opening between them to allow for sharing a treat.

Treats were placed on a swiveling plate, allowing one ape to push some or all of a given treatment to his or her neighbor.

The researchers manipulated two factors: the dependency and the reciprocity of the food exchange. In the dependency condition, the first ape could only get his or her treatment by sharing with the other ape.

In the independence condition, the first ape could get his or her treat without sharing. In the reciprocity condition, the roles were reversed and the experiment was repeated. In the non-reciprocity condition, the roles were not reversed.

The researchers also tested four-year-old children in a similar setup to compare their behavior with that of the apes.

The results: apes share more when they depend on each other and when they reciprocate

The results showed that apes were more likely to share their treat when they depended on their partner to get their own treat.

They shared approximately 70% of the time in this condition, compared to only 30% of the time in the condition where they did not depend on their partner.

The results also showed that apes reciprocated food positively and negatively. That is, they shared more with partners who had shared with them before, and less with partners who had not shared with them before.

The children showed a similar pattern of behavior, indicating that reciprocal food exchange is not unique to humans.

The implications: apes have the skills to cooperate and reciprocate with others

The study demonstrates that apes are capable of reciprocal food exchange given certain conditions. This implies that they have the cognitive and social skills to cooperate and reciprocate with others when it benefits them, as per The Royal Society.

The researchers suggest that this ability may have evolved in our common ancestor with apes, and that early humans had to reduce their aggression and increase their tolerance for food sharing in order to build stronger social ties.

The study also highlights the importance of studying apes in different contexts and settings, as their behavior may vary depending on the situation and the partner.

Also Read: Kids and Great Apes Create Similar Tools To Solve Problems

The comparison: how do other animals share food?

Reciprocal food exchange is widespread in human societies but rare in other animals. Most animals view food as a target for competition rather than cooperation, as per Nature.

However, some animals do share food under certain circumstances, such as kinship, friendship or mutualism.

For example, some birds and mammals share food with their offspring or mates as a form of parental care or pair bonding.

Some primates share food with their allies or friends as a way of maintaining social relationships or gaining support.

Some insects and fish share food with their partners as a part of mutualistic interactions or collective defense.

However, these forms of food sharing are not necessarily based on reciprocity. That is, they do not depend on whether the partner has shared food before or will share food later. Rather, they are based on other factors such as relatedness, familiarity, or benefit.

Reciprocity is a more complex form of cooperation that requires keeping track of past and future interactions and adjusting one's behavior accordingly.

Reciprocity can stabilize cooperation by rewarding cooperators and punishing defectors. Reciprocity can also foster cooperation by creating trust and reputation among partners.

Reciprocity is rare in nature because it requires high cognitive and social skills that most animals lack.

However, some animals have shown evidence of reciprocity in non-food contexts, such as grooming or helping.

For example, some primates groom each other reciprocally as a way of reducing stress or parasites. Some birds help each other reciprocally by taking turns incubating eggs or feeding nestlings.

Reciprocity in food exchange is even rarer because food is a more valuable and scarce resource than grooming or helping.

These experiments suggest that some animals have the potential to engage in reciprocal food exchange under certain conditions, such as familiarity, dependency or preference.

However, these experiments do not necessarily reflect the natural behavior of these animals in the wild, where food sharing may be more costly and risky.

Related article: Devastating Malaria Could Affect African Apes in Wild, Research Warns