Synchronised swimming makes dolphins optimistic: Study

Hyderabad: Can animals also be optimistic or pessimistic? Recent studies show that certain animals do make more positive or negative judgement depending on the situation and their emotional state, just like humans. This phenomenon is called cognitive bias. Cognitive bias is present in many aspects of our lives, whenever we make decisions about events with […]

Hyderabad: Can animals also be optimistic or pessimistic? Recent studies show that certain animals do make more positive or negative judgement depending on the situation and their emotional state, just like humans. This phenomenon is called cognitive bias. Cognitive bias is present in many aspects of our lives, whenever we make decisions about events with an unknown outcome. It has been shown that our current emotional state can influence whether decisions are more positive or negative in nature: either we expect the best or prepare for the worst.

Thanks to recent cognition research, we can test this in animals by training them in a judgement task.

Measuring optimism and pessimism

A judgement task works like this: first the animal is taught what will happen when certain cues appear. For instance, if we place a bowl in the left-hand corner of a room, it means they will receive a big reward. When the bowl is in the right-hand position, this means the animal gets no reward. Logically, the animal will run faster towards the positive cue and much slower towards the negative cue. After this priming, the bowl is placed in the middle of the room. If an animal still runs fast to the bowl, it is thought to be more “optimistic”, since it expects something positive to occur from an unknown event.

Past studies involving many species (for example rats, dogs and bees) have used this approach and shown that animals in poorer welfare situations, such as those in barren cages, or those subjected to veterinary exams or social isolation, make more pessimistic judgements. Those in enriched environments make more optimistic judgements. These experiments lead scientists to believe that cognitive bias testing is a valid way to discover the emotional state of the animal. The same test was done on dolphins too.

Optimistic dolphins

At the Parc Asterix dolphinarium in France, eight dolphins were taught to touch a target and return to their trainer. The dolphins then learnt that if the target was presented on one side of the pool, they would get a big herring. If the target was on the other side of the pool, they would receive only applause and eye contact from the trainer.

The dolphins were soon swimming faster when the target was in the herring position. It was then placed in the middle position and the level of optimism of each dolphin was measured by their swimming speed as they returned to the trainer. Those swimming faster back to the trainer were thought to be more optimistic, while the slower swimmers were not as hopeful about getting a reward. The results showed that indeed, the dolphins had different levels of optimism and pessimism, which remained the same over repeated days of testing.

But the most interesting discovery came when the cognitive bias was compared with individual observations of behaviour taken in the dolphins’ free-time.
In both the wild and captive environments, dolphins engage in social behaviour. Swimming in synchrony is thought to be an important affiliative behaviour which reinforces the bonding between individuals. In the park, it was observed that those dolphins who swam in synchrony more often were also the ones who made the most optimistic decisions. Positive social behaviour is an adaptation that help the dolphins survive in the wild, for example in the cooperative hunting behaviours seen in Florida.

Sociability and emotions

It was found that the most optimistic dolphins were also those who had performed most synchronised swimming in the two months prior to the test, but that there was no relation between optimism and the behaviour before that. This suggests that the optimism levels are linked to emotional states, as opposed to fixed personality characteristics. The emotional states are likely driven by the positive social behaviour occurring within the group at that time.
Dolphins’ emotional states, and their overall welfare in captivity, have recently incited much interest for scientists. The authors of this study believe that the level of synchronised swimming could be used as an indicator of emotional state, and thus could help to monitor and improve the animals’ social dynamics.