Temperament and lateralization in the domestic dog (Canis familiaris)

The authors investigated the relationship between paw preference (the paw with which dogs prefer to hold a food object) and temperament in the domestic dog (Canis familiaris). Hypotheses were based on the Valence-Specific Hypothesis, which broadly states that negative emotions are associated with the right hemisphere, and positive emotions are associated with the left hemisphere. To assess each dog's temperament, an owner-rated temperament questionnaire was administered to the owners of 73 pet dogs. The same dogs were tested for paw preference using a Kong (KONG Company, Golden, CO) stuffed with food and were subsequently classified as left-pawed, right-pawed, or ambilateral. A laterality index (LI) value was also calculated for each dog in the study to provide an indication of the strength and direction of its paw preference. Positive LI values reflected a preference for the right paw, whereas negative LI values reflected a preference for the left paw. The LI ranged from -100 to +100, with numbers closer to either extreme reflecting a stronger paw preference and a score of 0 indicating no preference. The absolute value of LI reflects the strength, but not direction, of paw preference and was included in some analyses. We found no evidence to support a relationship between paw preference and temperament, with the exception that lateralized dogs scored marginally higher than ambilateral dogs on a measure of stranger-directed aggression. We suggest that the temperament assessment used in this study may not be sensitive enough to detect differences between individuals based on their lateralization. Temperament factors were also compared with a number of "demographic" variables (e.g., age, sex, whether the dog was a purebred or a crossbreed, and the frequency of exercise) to determine the effect of these variables on temperament outcomes. (C) 2013 Elsevier Inc. All rights reserved.