Diversified leadership: a social solution of problems in schools of fish
Levin, L.E.; Grillet, M.E.
Acta Cientifica Venezolana 39(2): 175-180
1988
ISSN/ISBN: 0001-5504 PMID: 3251383 Document Number: 306892
Six isolated individuals of the schooling fish Aphyocharax erithrurus were trained in the avoidance paddle in successive reversals of a spatial discrimination. The number of errors in successive sessions decreased with each reversal, but no decrease was found in the total number of errors per reversal in successive reversals. This lack of improvement in the isolated fish contrasts with the performance of groups of the same species which did show an improvement in reversal learning and fewer number of errors per individual. The ability of the group is explained by the Diversified Leadership Hypothesis which states that the ordering of the individuals in a group changes when confronting different problems. Whenever there is an increase in the aversity (i.e., at the beginning of a reversal) the fish will group. The grouping is weaker in those fish in which the individual tendencies match the particular problem and they are thus less affected by the aversive contingencies. These individuals tend to separate from the group and thus will bias the behaviour of the other fish in their particular (and successful) behaviour. As a result of this, the more fit in solving a particular problem will circumstantially act as leaders. When the problem changes, other individuals would become the fitters and thus would act as leaders.