Can we measure fearfulness without inducing fear?

  • Key finding:

    Fearful temperament in primates has traditionally been assessed using the Human Intruder Test (HIT) in which duration of full-body freeze in response to approach by an unknown human is measured. This carries clear ethical implications, especially for animals with more fearful temperaments. We tested the applicability of a touch-screen task with putatively negative stimuli as a more standardizable and sensitive tool for measuring fearful temperament. Seventeen adult male rhesus macaques who had previously been assessed for fearfulness using the HIT were tested on a touch-screen task designed to measure two behavioral indices of fearfulness: behavioral inhibition and response-slowing. Behavioral inhibition in the touchscreen task was greatest amongst monkeys scored with most fearful temperament in the HIT. We propose touch-screen tasks provide a more standardized and sensitive approach for assessing fearful temperament in laboratory primates. Funded by COST Action PRIMTRAIN CA 15131

Links to Open Access Publications or DOI:


Bethell EJ, Cassidy LC, Brockhausen RR and Pfefferle D (2019) Toward a Standardized Test of Fearful Temperament in Primates: A Sensitive Alternative to the Human Intruder Task for Laboratory-Housed Rhesus Macaques (Macaca mulatta). Front. Psychol. 10:1051. doi: 10.3389/fpsyg.2019.01051