Contingent cooperation between wild female baboons

Abstract

The apparent rarity of contingent cooperation in animals has convinced many investigators that such reciprocity is unimportant, stimulating consideration of alternative explanations for cooperation, such as by-product mutualism and biological markets motivated by the likelihood of immediate reward. Nevertheless, there is also limited evidence that animals do sometimes rely on memory of recent interactions when behaving altruistically toward others. Here we describe a playback experiment conducted on wild female baboons, suggesting that contingent cooperation may occur among unrelated individuals, even when there is a temporal delay between the two cooperative acts. Hearing the recruitment call of an unrelated recent grooming partner caused subjects to move in the direction of the loudspeaker and approach their former partner, particularly when this partner had an infant. When the subject and her partner were close kin no such effect was observed. Subjects' responses were not influenced by any type of recent interaction, because prior grooming and prior aggression influenced their behavior in qualitatively different ways. Similarly, their responses were not prompted only by the motivation to resume friendly interactions, because prior grooming alone did not elicit approach. Instead, subjects were most likely to approach their former grooming partner when they had also heard her recruitment call. Results suggest that at least some forms of cooperation in animals may be based on memory of specific recent interactions. D uring the last decade there has been increasing skepticism about the relevance of contingent cooperation in the social behavior of animals. Because most cooperative behavior occurs among long-term partners (often kin) for whom any single altruistic act may be relatively insignificant, many investigators are now convinced that the sort of contingent reciprocity first proposed by Trivers (1) is both rare and fragile in nature (e.g., refs. 2-3). Although there is limited experimental (e.g., refs. 4-8) and correlational (e.g., refs. 9-11) evidence that unrelated animals may sometimes rely on memory of recent interactions when behaving altruistically toward others, interpretation has been complicated by a paucity of convincing examples, the absence of important controls in some early tests (e.g., ref. 4), and several experimental studies of captive apes, suggesting a general insensitivity to contingency in cooperative tasks (e.g., refs. 12-13). These concerns have stimulated consideration of alternative explanations for cooperation among unrelated partners, such as by-product mutualism and biological markets motivated by the likelihood of immediate reward (e.g., refs. 14-16). The change in focus has also been prompted by doubts that animals possess the requisite cognitive abilities to sustain contingent cooperation. These include the ability to delay reward, to quantify past cooperative acts, to plan and anticipate future outcomes, and to detect and punish cheaters (e.g., refs. 17-20).Although these obje...

Coalitions in theory and reality: a review of pertinent variables and processes

“…Chimpanzees, for example, may hold out an open hand to another to solicit his or her support, embrace the other, or sit right behind an ally, hooting along with his vocal challenge of the common target (de Waal, 1982). De Waal & van Hooff (1981) provide a detailed analysis of side-directed behaviour in chimpanzees (see also Slocombe & Zuberbühler, 2007), but species-typical recruitment behaviour is also well-known of macaques (e.g., de Waal, 1976;Gouzoules & Gouzoules, 2000), baboons (e.g., Noë, 1990;Cheney et al, 2010), and capuchin monkeys, which encourage each other in a so-called 'overlord', with one coalition partner mounted on the shoulders of the other, while both threaten a common opponent (Perry et al, 2004;Figure 1). All of these behaviours may add to the degree of coordination within the coalition.…”

Food transfers in capuchin monkeys: an experiment on partner choice

“…Available evidence, however, suggests a more complex picture. Although recent events do affect the likelihood to behave cooperatively [9], animals also accept shortterm imbalances in their within-dyad exchanges. Overall, long-term exchanges are often more balanced than short-term exchanges [10,11].…”

“…While the former is tested by examining the relations between events over short time-scales (minutes to hours; [9]), the latter is tested by examining partner choice over much longer time-scales (months; [6]). The choice of these different time scales is based on the assumption that the two decision-making processes differ in their tempo.…”

Urinary oxytocin and social bonding in related and unrelated wild chimpanzees

“…Although the maintenance of enduring social bonds is associated with fitness benefits, whether these are between kin [1,2] or non-kin [6,11], the underlying mechanism of how such relationships are maintained over time is unclear. Contingent reciprocity, where one remembers a service given by another and then offers a service in return at a later date, offers a possible explanation, although this mechanism is rare in animals [16,17] and has been found among individuals that interact at low rates [18]. By contrast, individuals that interact at high rates and have strong, stable social bonds typically show short-term imbalances in services that are more equitable when calculated over months [19][20][21].…”