Individual Characteristics: Weaving Psychological and Ethological Approaches

Abstract

The chapter begins by outlining the development of the questionnaire for assessing individual characteristics of rhesus monkeys in the Madingley colony. The steps taken in preparing items, obtaining reliability and validity, and condensing items are presented, along with examples of how scores arising from principal component analyses can be put to use. In our own research, the scores were referred to simply as ``individual characteristics,{''} in an attempt to avoid going beyond the data and implying either heritability or human-like qualities. Fearfulness is then explored as it is a particularly strong dimension, not only for our monkeys, but also across many species, from fish to humans. This suggests that fearful behavior may have been selected for during the course of evolution, with a presumed function of protection from harm. Within a species, individual differences in fearfulness may be a result of differing selection pressures, and recent research on how individual variation could be adaptive is discussed.