March 18, 2009

Study: Adult-to-young ratio important

French scientists say they've determined the adult-young ratio is much more important to a child's social development that just the mere presence of adults.

Marie Bourjade, Alice de Boyer des Roches and Martine Hausberger of the University of Rennes, France, studied the effects of adult-young ratios in naturally-formed groups of Przewalski horses on aggression rates and social cohesion of young horses.

Przewalski horses constitute a very adequate model for investigating the educational roles of experienced adults as the species forms year-round stable groups with both maternal and paternal carers, as well as the presence of unrelated adult females, Bourjade said

The scientists said their findings revealed striking differences, depending on the adult-young ratios.

When in a group in which adult-young ratios were low, young horses were more aggressive and more segregated from adults and they established tighter bonds with other young, the scientists reported. "Tighter bonds between young in groups with low proportions of adults could be a factor which decreases the attention paid to adults and probably reduces their influence as regulators of the behavior of young, in particular their aggressive behavior.

Adult-young ratios appear to be an important feature of social settings that must be taken into account as a potential modulator of social influence when evaluating developmental processes.

The study appears in the online journal PLoS One.