Dolphins and Displacement

As an animal living in a natural habitat in which various factors relevant to one’s survival move about freely, it is greatly advantageous to be able to reason about the location and movement of objects. This element of spacial cognition is  found in humans as well as in great apes, as previous studies have shown evidence of similar cognition. While there is some evidence of the same in monkeys, the research on marine mammals is greatly absent.

Dolphins are widely known to be highly intelligent creatures who share some of the cognitive skills that human’s possess. Behaviours such as imitation, mirror self-recognition, means-ends reasoning, and the
ability to understand symbols and other external representations were all found to exist in dolphins in previous studies.

A study conducted in 2010 by Kelly Jaakkola et. al., was published in Animal Cognition that sought out to see whether dolphins posses the ability to reason about the movements of hidden objects through a series of four experiments.

Several bottle nose dolphins were trained to play a “find the object” game and were tested through various version of what is essentially the carnival cups and shell game. The trials consisted of an experimenter hiding the object in a bucket using one of three displacement techniques and a dolphin was then asked where the object was. The dolphin would then tap on it’s decision and the experimenter would then remove the lids.

It was found that the dolphins did well when it came to following the movements of an object they had seen and were placed in buckets. The introduction of cylinder to increase difficulty and essentially make the displacement “invisible” was not as successful. However, the use of an experimenters hands instead of a cylinder had greater success. The implementation of experimental controls identified that this behaviour may have been the result of the dolphins, “they did so by learning local rules rather than via a true representation of the movement of hidden objects” (Jaakkola et al. 2010). It is another issue of why the dolphins had such difficulty tracking hidden movements but it simultaneously offers other avenues for future work to consider. Perhaps the newness of not being able to see or echo-locate objects can wear off and yield different results. This can shed some light onto the application and significance of recognition abilities and how they apply to various aspects of an animals life.

Jaakkola, Kelly.,  Guarino, Emily., Rodriguez, Mandy., Erb, Linda., Trone, Marie. “What do dolphins (Tursiops truncatus) understand about hidden
objects?” Animal Congition. 13:103–120, 2010.DOI 10.1007/s10071-009-0250-z