Association Between Lateral Bias and Personality Traits in the Domestic Dog (Canis familiaris)

Behavioral laterality reflects the cerebral functional asymmetry. Measures of laterality have been associated with emotional stress, problem-solving, and personality in some vertebrate species. Thus far, the association between laterality and personality in the domestic dog has been largely overlooked. In this study, we investigated whether lateralized (left or right) and ambilateral dogs differed in their behavioral response to a standardized personality test. The dog's preferred paw to hold a Kong ball filled with food and the first paw used to step-off from a standing position were scored as laterality measures. The Dog Mentality Assessment (DMA) test was used to assess 5 personality traits (e.g., sociability, aggressiveness) and a broader shy-boldness dimension. No differences emerged between left-and right-biased dogs on any personality trait. Instead, ambilateral dogs, scored using the Kong test, scored higher on their playfulness (Z = -1.98, p =.048) and Aggressiveness (Z = -2.10, p =.036) trait scores than did lateralized (irrespective of side) dogs. Also, ambilateral dogs assessed by using the First-Stepping test scored higher than lateralized dogs on the Sociability (Z = -2.83, p =.005) and Shy-Boldness (Z = -2.34, p =.019) trait scores. Overall, we found evidence of a link between canine personality and behavioral laterality, and this was especially true for those traits relating to stronger emotional reactivity, such as aggressiveness, fearfulness, and sociability.