Lush, J., Ijichi, C. 2018. A preliminary investigation into personality and pain in dogs. Journal of Veterinary Behavior 24, 62-68.
Adherence to basic animal welfare standards involves effective monitoring and control of pain, especially in a veterinary setting. Assessment relies on behavioral and physiological indicators. However, individual differences in physiology mediate consistent individual differences in behavior, referred to as “personality”. Therefore, personality may confound measurements of pain. The current work is a preliminary investigation into whether extraversion and neuroticism are associated with differences in individual behavioral and physiological responses to pain. Twenty dogs were observed during recovery from routine castration in a clinical setting. Core temperature was recorded using infrared thermography on admission, 15 minutes after extubation and every 30 minutes thereafter, until the subject was collected by their owner. Behavior during recovery was scored using Short-Form Glasgow Composite Measure Pain Scale at the same intervals as infrared thermography readings. Personality was measured using Monash Canine Personality Questionnaire–Revised, and owners rated their dog's tolerance to pain on a 5-point Likert scale. Pain score did not have an association with eye temperature discrepancy or core temperature changes from control, indicating it may not predict affective response to pain. More highly “extravert” subjects had significantly higher pain scores (P = 0.031), despite experiencing similar tissue damage. More “extravert” subjects showed significantly greater right eye temperature (P = 0.035), suggesting hemispheric dominance. “Neuroticism” had no association with physiological or behavioral responses to pain. Finally, owners were not able to predict their dog's behavioral or physiological response to pain. These results indicate that personality may be a useful clinical tool for assessing individual differences in response to pain, whereas owners' ratings of their dog's response are not reliable.