Chimpanzees’ flexible targeted helping based on an understanding of conspecifics’ goals

Abstract

Humans extensively help others altruistically, which plays an important role in maintaining cooperative societies. Although some nonhuman animals are also capable of helping others altruistically, humans are considered unique in our voluntary helping and our variety of helping behaviors. Many still believe that this is because only humans can understand others’ goals due to our unique “theory of mind” abilities, especially shared intentionality. However, we know little of the cognitive mechanisms underlying helping in nonhuman animals, especially if and how they understand others’ goals. The present study provides the empirical evidence for flexible targeted helping depending on conspecifics’ needs in chimpanzees. The subjects of this study selected an appropriate tool from a random set of seven objects to transfer to a conspecific partner confronted with differing tool-use situations, indicating that they understood what their partner needed. This targeted helping, (i.e., selecting the appropriate tool to transfer), was observed only when the helpers could visually assess their partner's situation. If visual access was obstructed, the chimpanzees still tried to help their partner upon request, but failed to select and donate the appropriate tool needed by their partner. These results suggest that the limitation in chimpanzees’ voluntary helping is not necessarily due to failure in understanding others’ goals. Chimpanzees can understand conspecifics’ goals and demonstrate cognitively advanced targeted helping as long as they are able to visually evaluate their conspecifics’ predicament. However, they will seldom help others without direct request for help.

Gricean Communication and Cognitive Development

“…Such behaviours can make some acts of intentional communication more easily interpretable than others, by providing rich evidence for a speaker's communicative intentions (Moore, 2013b). Additionally, Sperber and Wilson (1995;2002) propose the existence of a cognitive module, unique to humans, that processes food, they respond appropriately to requests produced using an ambiguous begging gesture (Yamamoto et al, 2012). This suggests that they can, in at least limited contexts, make inferences about an interlocutor's communicative goal.…”

Origins of Human Cooperation and Morality

“…Moreover, Melis and colleagues (2011) found that chimpanzees will also release a hook to send food down a ramp to a desirous conspecific, if it is clear that they cannot get the food themselves and if the recipient actively signals his need. Finally, Yamamoto and colleagues (2009) observed chimpanzees giving tools to others that needed to rake in food for themselves, and more recently showed that chimpanzees demonstrate flexible "targeted" helping, i.e., giving the specific tool that the conspecific needs from an array of possible tools (Yamamoto et al 2012).…”

Monkeys benefit from reciprocity without the cognitive burden

“…The main mechanism for human prosociality is assumed to be empathy (4), which has been hypothesized to extend to all mammals (5). After a period during which there was a lack of evidence for nonhuman primate prosociality, including claims of human uniqueness in this regard (6,7), carefully controlled experiments have demonstrated well developed prosocial tendencies in monkeys (8)(9)(10) and apes (11)(12)(13)(14). The ecological validity of experimental findings on prosociality is supported by the many naturalistic observations of the same tendencies expressed spontaneously among chimpanzees and other nonhuman primates (3,15,16).…”