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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Cooperative pulling paradigm | 6/10 | https://en.wikipedia.org/wiki/Cooperative_pulling_paradigm | reference | science, encyclopedia | 2026-05-05T09:49:48.882099+00:00 | kb-cron |
Molesti and Majolo tested a group of wild Barbary macaques (Macaca sylvanus) in Morocco to see if they would cooperate, and if so, what determined their partner choice. Macaques live in complex social environments and are relatively tolerant socially. After solo training, the researchers presented a loose-string apparatus for the cooperative task, which the animals were free to use. Most animals that passed solo training were successful in spontaneously cooperating to obtain food (22 out of 26). More than half the pairs that chose to cooperate were juvenile-adult pairs. More than two monkeys pulling was never observed; stealing food from a partner was rare. After a first successful cooperation, they were more likely to pull when a partner was directly available, but this was not always the case. Molesti and Majolo did not rule out that pulling while no one held or pulled the other end of the rope was simply a signal to actively recruit a potential partner. The researchers randomly introduced control trials in which the solo apparatus was set up as well. The macaques preferred to get the food alone when a partner was not needed during the control. The extent to which a monkey tolerated another was a good predictor for initiating cooperation. An individual was also found to be more successful with partners with whom they had a strong social bond. Pairs sharing a similar temperament were more likely to initiate cooperation. The quality of the relationship seemed to play an important role in the maintenance of cooperation over time.
==== Humans ==== Rekers, Haun, and Tomasello tested the cooperation abilities and preferences of humans (Homo sapiens) and compared them to chimpanzees. The researchers provided 24 three-year-old children with some basic training in pulling food rewards towards themselves; in pairs using a loose-string setup, and solo training in which the two ends of a rope were tied together. They then tested the children in an apparatus choice set-up. On one side was the loose end of a rope that threaded through the apparatus to the other child. On the other side were two ends of a rope that when pulled would pull a platform towards both the child and their partner. Both the joint-operator platform and the solo-operated platform were holding two food dishes, all containing the same amounts of food. That is, from a partner's perspective, on one side the child had to pull to get food; on the other the partner could get food without any effort. The children chose the joint-operated board in 78% of trials. The researchers then changed the design to ascertain if this choice preference was due to wishing to avoid freeloading and it may be that the children did not like their partner getting food without making any effort. In the modified set-up the partners never received any reward, not from the joint-operated apparatus and not from the solo-operated apparatus. Children again chose the joint-operated platform significantly more often, in 81% of trials. As in the first study, there was no significant difference in the time taken to obtain the food reward between using one side or the other. These results suggest that to obtain food, children prefer to work together with a partner as opposed to working alone. The chimpanzees in their study appeared to choose between the two platforms randomly, indicating no preference to work collaboratively. However, Bullinger, Melis, and Tomasello showed that chimpanzees actually exhibit a preference for working alone, unless cooperation is associated with higher pay-offs.
=== Other mammals ===
==== Hyenas ====
Captive spotted hyenas (Crocuta crocuta), social carnivores that hunt in groups, have cooperated to obtain food rewards by pulling ropes in an experimental setting. Mimicking the natural choice hunting hyenas face when deciding which of many prey to jointly attack, researchers Drea and Carter set up two devices instead of one, as previously used in all cooperative pulling tasks with other species. With four ropes to pull from, the animals had to pick the two belonging to the same device to be successful. If two vertically suspended ropes were simultaneously tugged, a spring-controlled trap door of an elevated platform was opened and previously hidden food dropped to the floor. Another innovation was the introduction of more than two animals. One of the many factors the researchers controlled for was the Clever Hans effect (an effect in which humans unwittingly provide cues to animals), which they did by removing all humans from the test and by recording experiments on video. After extensive solo trials, all hyenas were successful in cooperating, displaying remarkable efficiency even on their first try. On average, hyenas pulled on ropes more often when their companion was nearby and available to fulfil its partnership role. With only a few solo trials, the success rate of the cooperation task was very low for pairs. In groups of four hyenas, all trials were successful, regardless of the number of reward platforms. Thereafter, group exposure to a cooperation task had enhancing effects on pairwise performance. Social factors such as group size and hierarchy played a role. For instance, groups with a dominant member were far less successful than groups without, and lower-ranking animals were faster and consistently successful. When pairing experienced cooperators with animals new to the cooperation task, the researchers found that experienced animals monitored the novices and modified their behavior to achieve success. Despite initial accommodation, the pattern of rank-related social influences on partner performance also appeared in these tests with novices.
==== Dogs ====