Testing a shortened personality questionnaire with captive rhesus macaques (Macaca mulatta) at the Oregon National Primate Research Center

Personality ratings by research and care staff familiar with individual animals are a reliable and valid way to assess animal personality. However, many questionnaires are too long and thus too time-consuming for care staff, precluding their use in large samples. We sought to assess the inter-rater reliability (ICC[3,k]) and validity of a 12-item version of the Hominoid Personality Questionnaire. We collected ratings on 41 rhesus macaques (mean age = 4.59, 2.5 raters/animal) group-housed in three enclosures at the Oregon National Primate Research Center. Using published definitions of rhesus personality, we calculated scores for the dominance, confidence, openness, and anxiety dimensions. The inter-rater reliabilities of these dimensions were .78, .70, .41, and.38, respectively. We examined the correlations between these dimensions and a behavioral measure of rank (i.e., Normalized David’s Scores) collected using 15-minute continuous focal observations (19.15 observations/animal). Higher rank was significantly (ps < .001, dfs = 39) correlated with dominance (r = .68), confidence (r = .71), openness (r = .55) and anxiety (r = -.60). These results suggest that four personality dimensions derived from a brief questionnaire are reliable and demonstrate convergent validity. This questionnaire will be useful for studies of large samples or facilities with large populations where staff may be unable to complete longer questionnaires or collect detailed behavioral data due to time constraints.