Investigation of breed-related variation in judgement bias, sustained gaze and cylinder task performance in healthy pet dogs.

Judgement bias tasks are increasingly used to infer affective state in animals, but the extent to which affect-related judgement varies systematically across dog breeds remains unclear. In a cross-sectional prospective study, 118 healthy client-owned adult dogs from 10 breeds/breed types completed a spatial judgement bias task and other cognitive tasks including sustained gaze and a cylinder task. Dogs also underwent emotional reactivity testing and owner assessment using the Canine Behavioral Assessment and Research Questionnaire (C-BARQ). Breed effects and cross-domain associations were evaluated using nonparametric and covariate-adjusted regression models. Judgement bias and delta scores showed no consistent breed differences. Although breed was significant in an initial covariate-adjusted ordinal model of judgement bias, it was not retained after AIC-based model reduction. Judgement bias was not associated with novel object responses, disgruntled stranger scores, or most C-BARQ traits. Higher familiar-dog aggression scores were associated with lower odds of pessimistic bias outcomes, and disgruntled stranger performance correlated positively with C-BARQ stranger-directed fear. In contrast, sustained gaze duration differed markedly by breed and remained breed-dependent after adjustment, with retriever breeds showing longer gaze durations than Maltese and several other breeds. Cylinder task outcomes showed subtler breed-related effects, but familiarisation trial number and owner-reported excitability were more consistent predictors than breed. These findings suggest that, in healthy pet dogs, affect-related judgement under ambiguity is shaped more by individual-level factors than by breed, whereas sustained gaze scores and some cylinder task scores show some breed-related patterning. Very few breed differences were found overall, and the results of this study reinforce the value of multimodal approaches to canine affect and cognition, and the use of caution regarding breed stereotypes.