Personality traits of captive lion-tailed macaques will be investigated in this study. Because each social group is a unique constellation of individuals, understanding differences in personality is important for a better understanding of primate social behavior, groups, and species. In laboratory tests, knowing how personality contributes to the different responses of animals under the same conditions will enable researchers to interpret results more clearly. Human personality research will also benefit, because prototypes of human traits can be studied through nonhuman primate models when human testing would be difficult or unethical, such as when studying the biologic basis of personality. Social and environmental conditions of nonhuman primates can also be manipulated to explore their influence on personality as well. In this study, personality traits will be assessed by observing the behavior of 52 captive macaques in 8 groups, kept in different social groupings and/or types of housing. A principal components analysis, a statistical technique used in human personality research, will group behaviors that occur together to determine major factors of personality. Two personality profiles will be developed for each animal: one based on the frequency of behaviors and a second using personality factors from the principal components analysis. Individual profiles will be averaged to form a female and a male species profile for both behavioral frequency and for personality factors. In addition, the effect of sex, dominance rank, ratio of males to females in the group, and spatial density of housing (square feet/animal) on personality will be explored. The method used in this research can integrate the results of many different investigators, because it is divided into specific traits, each defined by commonly studied primate behaviors. Because it facilitates research comparing primate groups and species, it should help untangle the complex mix of genetic, social, and environmental influences on both human and nonhuman primate personality.
