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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Cooperative pulling paradigm | 9/10 | https://en.wikipedia.org/wiki/Cooperative_pulling_paradigm | reference | science, encyclopedia | 2026-05-05T09:49:48.882099+00:00 | kb-cron |
Rooks (Corvus frugilegus) are large-brained members of the bird family Corvidae. They live in big groups and have a high level of social tolerance. Researchers Seed, Clayton, and Emery set up a loose-string experiment with eight captive rooks. They were first trained in a solo task, with the string ends placed at 1 cm, 3 cm and ultimately 6 cm apart (0.4, 1.2, and 2.4 inch respectively). A pair's willingness to share food was then tested, and was found to differ somewhat between pairs, although food was rarely monopolized by a dominant bird. In the cooperative task, all pairs were able to solve the cooperation problem and retrieve food; two pairs managed this in their first session. Food sharing was a good predictor for successful cooperation. In a subsequent delay test, where one partner had access to the apparatus first, all rooks pulled the string without waiting for their partner to enter the test area in the majority of trials. In a second variant, birds were given a choice between a platform they could operate successfully alone and one that required a pulling partner. When tested alone, four of the six rooks showed no significant preference for either platform. Seed, Clayton, and Emery concluded that although successful at the cooperation task, it seemed unlikely that the rooks had an understanding of when cooperation was necessary. Researchers Scheid and Noë subsequently found that successful cooperation in rooks depended to a large extent on their temperament. In their loose-string experiment with 13 captive rooks they distinguished between bold and shy animals. The results were mixed, ranging from some pairs cooperating successfully every time to some pairs never cooperating. In 81% of cases a rook should have waited for a partner, but it did not and started pulling. Scheid and Noë concluded their experiment provided no evidence for or against rooks having an understanding of the task. They attributed any cooperation success to common external cues and not coordination of actions. But all subjects did better when they were paired with a bolder partner. The researchers suggested that in evolution, cooperation can emerge because bolder individuals encourage a risk-averse one to engage.
==== Ravens ====
Massen, Ritter, and Bugnyar investigated the cooperative capabilities of captive common ravens (Corvus corax), a species that frequently cooperates in the wild. They found that without training ravens cooperated in the loose-string task. The animals did not seem to pay attention to the behavior of their partners while cooperating, and, like rooks, did not seem to understand the need for a partner to be successful. Tolerance of their partner was a critical factor for success. In one condition the researchers let ravens choose a partner from a group to cooperate with. Overall success was higher in this condition, and again, individuals that tolerated each other more had more success. The ravens also paid attention to reward distribution: they stopped cooperating when being cheated upon. Asakawa-Haas, Schiestl, Bugnyar, and Massen subsequently ran an open-choice experiment with eleven captive ravens in a group setting, using nine ravens from one group and two newcomers. They found that the ravens' decision which partner to cooperate with was based on tolerance of proximity and not on whether they were part of the group or not. The ravens in this experiment learned to wait for their partner and inhibit pulling the string too soon.
==== Grey parrots ====
Researchers Péron, Rat-Fischer, Lalot, Nagle and Bovet had captive grey parrots (Psittacus erithacus) try to cooperate in a loose-string experimental set-up. The grey parrots were able to act simultaneously but, like the rooks, largely failed to wait for a partner in the delay task. They did not make any attempts to recruit a helping partner. The parrots did take the presence of a partner into account, since they all pulled more when a partner was present, but this could be explained by instrumental learning rather than a real understanding of the task. The researchers also gave the parrots a choice between two apparatus, one from the solo task and one from the loose-string task, now stacked with double the food per bird. Two of the three parrots chose the solo apparatus when alone, and two of the three parrots preferred the joint-task apparatus when tested with a partner. When paired up, social preferences and tolerance affected the likelihood a pair cooperated.
==== Kea ====