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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Cooperative pulling paradigm | 8/10 | https://en.wikipedia.org/wiki/Cooperative_pulling_paradigm | reference | science, encyclopedia | 2026-05-05T09:49:48.882099+00:00 | kb-cron |
Elephants have a complex social structure and large brains that enable them to solve many problems. Their size and strength do not make them easy candidates for experiments. Researchers Plotnik, Lair, Suphachoksahakun, and de Waal adapted the apparatus and task to elephant requirements. They trained captive Asian elephants (Elephas maximus) to use a rope to pull a sliding platform with food on it towards themselves. Once the elephants managed this solo task, the researchers introduced a loose-string apparatus by threading the rope around the platform. At first, two elephants were released simultaneously to walk side by side in two lanes to the two loose ends of the rope. Using their trunks the animals coordinated their actions and retrieved the food. At this stage they could simply be applying a 'see the rope, pull the rope' strategy. To see whether they understood the requirements of the task the researchers introduced a delay for one elephant, initially of 5 seconds and ultimately of 45 seconds. At first the lead elephant failed to retrieve the food but was soon seen to wait for a partner. Across 60 trials the first elephant waited for the second one before pulling in most cases. In a further control the researchers prevented the second elephant from being able to access its end of the rope. In almost all of these cases the first elephant did not pull the rope, and four of the six returned when they saw the other rope end was not going to be accessible to their partner. The researchers concluded that this suggested the elephants understood they needed their partner to be present and to have access to the rope to succeed. One elephant never pulled the rope but simply put her foot on the rope and let the partner do all the pulling. Another one waited for his partner's release at the starting line rather than waiting at the rope. Plotnik, Lair, Suphachoksahakun, and de Waal conceded that it is difficult to distinguish learning from understanding. They did prove that elephants show a propensity towards deliberate cooperation. The speed with which they learned the critical ingredients of successful cooperation puts them on par with chimpanzees and bonobos.
==== Otters ====
Schmelz, Duguid, Bohn, and Völter presented two species of captive otters, giant otters (Pteronura brasiliensis) and Asian small-clawed otters (Aonyx cinerea), with the loose-string task. Both species raise young cooperatively and live in small groups. Because giant otters forage together but small-clawed otters do not, the researchers expected the giant otters to do better in the cooperative pulling experiment. After solo training, they tested both species in a group setting, to maintain ecological validity. The results showed that most pairs of otters were successful in pulling food rewards to themselves. Contrary to expectation, there was no difference between the species in success rate. In a subsequent experiment the researchers first lured the group away from the apparatus into the opposite corner of the enclosure. Then they put food on the apparatus and observed what happened when the first otter arrived at the nearest end of the rope, as there was no partner yet at the other end. Very few trials led to success in this condition as otters pulled the rope as soon as they could. The researchers concluded from this that the otters did not understand the necessary elements of successful cooperation, or, alternatively, they understood but were unable to inhibit the desire to reach for the food. When the same task was repeated with a longer rope, success rate did go up, but the otters appeared unable to learn from this and be successful in the next task with the rope length restored to the original length. Schmelz, Duguid, Bohn, and Völter suggested that an understanding of cooperation may not be required for successful cooperation in the wild. Cooperative hunting may be possible through situational coordination and mutualism, without any complex social cognitive abilities.
==== Dolphins ====
Two groups of researchers (first Kuczaj, Winship, and Eskelinen, and then Eskelinen, Winship, and Jones) adapted the cooperative pulling paradigm for captive bottlenose dolphins (Tursiops truncatus). As apparatus they used a container which could only be opened at one end if two dolphins each pulled a rope on either end. That is, the dolphins would have to face each other and pull in opposite directions. They first attached the container to a stationary dock so a single dolphin could learn to open it and get the food reward. Then they ran trials in which the container was free floating in a large test area with six dolphins. In Kuczaj, Winship, and Eskelinen's study, only two dolphins interacted with the container. In eight of the twelve trials they pulled simultaneously and obtained food. Once, they also managed to open the container through asynchronous pulling, and once a single male dolphin managed to open it by himself. Kuczaj, Winship, and Eskelinen admitted that this behavior may appear to be cooperation but could possibly be competition. They conceded it is possible that the dolphins did not understand the role of the other dolphin, but instead simply tolerated it pulling on the other side. King, Allen, Connor, and Jaakkola later argued that this design makes for a competitive 'tug-of-war', not cooperation, and any conclusions regarding cooperation should therefore be invalid.
=== Birds ===
==== Rooks ====