Individuals differences in exploratory behavior of prairie voles, Microtus ochrogaster

Behavioral syndromes, also called behavioral phenotypes or profiles, are defined as correlations between behaviors in different environmental contexts or testing situations. But how does one accurately measure and determine what behavioral syndrome a subject demonstrates? The popularity of behavioral syndrome research has yielded many different methods of examining and interpreting behavioral phenotypes. For example, many research teams have identified behavioral syndromes by correlating behaviors from different tests representing different contexts such as exploration, foraging or social interaction however many of these same researchers failed to test whether there is any correlation of behaviors within a single context. As a result, some other researchers question whether correlated behaviors across contexts are truly related or if those behavioral correlations are artifacts. My objective was to determine if prairie voles, Microtus ochrogaster, demonstrate correlated behaviors in different situations within a single context -- exploration. Exploratory behavior responses were examined in three novel situations: an open-field with novel objects, a two-way novel choice apparatus, and a complex maze. For each situation, behavioral responses were identified by key dependent variables determined by Principal Components Analysis. Three different exploratory responses emerged: the open-field test with novel objects measured interactive behavior, the complex maze measured general activity behavior, and the two-way novel choice test measured proactive/reactive behavior in response to novel environments. For each test, subjects were ranked from low to high exploratory tendency, thus creating three exploratory behavioral responses. The exploratory behavioral responses were compared and there was no correlation across tests, thus providing no evidence of an overall exploratory behavioral syndrome in this species. In light of these findings, each exploratory test appears to measure different and uncorrelated aspects of exploratory behavior. Recently, an increasing number of studies of behavioral syndromes similarly have failed to find a correlation of behaviors across tests or contexts. These results raise questions about the ability to identify personality types in animals and the validity of behavioral syndromes as a general attribute of animal behavior.Key words: individual differences, behavioral phenotypes, behavioral syndromes, exploratory behavior, open-field test, prairie vole...