Comprehensive coverage

Prosocial behavior in fish

A new study conducted at the University of Haifa found that even the sniper fish, which lack the "higher" areas of the cerebral cortex, which are seen as being responsible for social behavior, act in a pro-social way towards their friends, until they feel "cheated"

swordfish Photo: Dr. Orit Nafha, University of Haifa
Sniper fish Photo: Dr. Orit Nafha, Haifa University

Is a social tendency unique to a person? A new study conducted at the University of Haifa and published in the journal COMMUNICATIONS BIOLOGY found that snapper fish, which do not have the "higher" areas of the cerebral cortex, which are seen as responsible for social behaviors, acted in a social manner towards their friends, and stopped acting that way when they felt "cheated". 

"The research findings show that even fish demonstrate complex social behaviors, which could indicate that sociality is an evolutionary tendency among different animal species. Apparently, these social traits are important for survival in both cooperative and competitive societies, such as the fish we studied," said Dr. Orit Nefha, from the University of Haifa, the study's editor.    

Humans operate most of the time in social contexts and depend on others for survival, and hence understanding the intentions and behavior of others is an important ability that allows us, humans, to survive successfully in a social environment. According to the researchers, today in the research literature there is a tendency to focus on the involvement of the "higher", cortical, areas of the brain in the study of social behaviors, which produces a bias in associating them with "higher" functions while neglecting the possible contribution of the "subcortical" areas that developed evolutionarily at earlier stages.

In the current study, Dr. Nafha, research student Dana Wilker, Prof. Simon Shamai Tzuri and Prof. Shay Gabbai from the School of Psychological Sciences and the Institute for Information Processing and Decision Making (Hamek'a) at the University of Haifa asked to examine the evolutionary basis for the behaviors of social cooperation and social fairness and how these behaviors are expressed in competitive species lacking cortex. As the research model, the researchers used the archerfish, known as competitive fish, and sometimes even kleptomaniacs, without a developed cerebral cortex, with a natural ability to hunt insects by shooting a water jet. The sniper fish are even able to learn and distinguish between artificial stimuli presented to them on the back of a computer screen as part of an experiment, and respond to them by spraying a jet of water in exchange for a reward (food).

For the purpose of the study, the researchers used a double aquarium divided into two with a transparent partition, where on each side there is a sniper fish that cannot pass from side to side and each fish received food on its side. In the first experiment, the spitting fish was given the opportunity to choose between two targets: a non-social target (for example a black starfish) that when he spits on, only he receives a reward, and a social target (for example a red starfish), that when the fish spits on it he receives food and in addition the other fish found Beyond the partition receives food. The colors were changed in the second stage of the experiment, each color was used both for personal reward and for shared reward, and this to avoid an alternative explanation according to which the fish prefer a certain color, and not necessarily a social behavior.

In both phases, all the fish in the study always preferred the social goal - that is, food for both them and their friend beyond the glass.

Then in a control experiment the researchers removed the passive fish from the other side of the aquarium and the spitting fish were asked to choose between 2 targets again: one rewarded only them with food and the other rewarded them and the empty side of the aquarium. The results of this part showed that without fish on the other side, there was no preference for fish regarding one goal or another.

Finally in the last experiment, the researchers looked at what happens when the passive fish gets more food than the active fish. In this condition, the social target rewarded the spitter with one piece of food and the passive fish with two pieces of food, while the non-social target rewarded only the spitting fish with a single piece of food. At this point the spitting fish stopped choosing the social goal, which would reward their friend even more.

It is true, but it is possible that its basis is different," said Dr. Nafha.

The results of all the experiments show that even fish living in a competitive social environment will exhibit social behavior as long as the reward is equal but will stop doing so if the other fish earns more than them.

"The research demonstrates for the first time in laboratory conditions that the sniper fish, known as a competitive fish, behaves in a pro-social manner under certain conditions and stops behaving this way when the product creates an unequal situation. Furthermore, so far most studies have looked at social and cooperative animals that raise offspring together. This study shows for the first time social behavior in competitive and kleptomaniac species, so although it is social behavior, it may have a different basis," said Dr. Nafha.

Leave a Reply

Email will not be published. Required fields are marked *

This site uses Akismat to prevent spam messages. Click here to learn how your response data is processed.

Skip to content