Abstract In humans, many behavioural and cognitive traits are moderately-to-highly heritable, with cognitive measures tending to increase in heritability over the lifespan, and personality measures tending to decrease in heritability. However, fewer studies have explored the heritability of analogous traits in non-human animals or the changes of these heritability estimates across development. We phenotyped 415 dog puppies and 520 adults—from the assistance dog organization Canine Companions—on the Dog Cognitive Development Battery. Scores across tasks were weakly intercorrelated, and we observed a wide range of estimated heritabilities. Using an animal model and the population pedigree, the most heritable traits in puppies involved looking to a human when spoken to (‘human interest looking’, h2 = 0.32) and reactions to a novel object (h2 = 0.56) and surprising events (h2 = 0.61). Most heritability estimates remained relatively stable or decreased over development, although human interest looking time (h2 = 0.36) and novel object reactions (h2 = 0.31) remained moderately heritable in adults. Similar heritability estimates were found using a genomic-relatedness matrix in a subset of individuals (69% of puppies, 96% of adults). Our results address the psychological structure of individual differences early in dog development, characterize the extent to which these traits are heritable and available to selection, and demonstrate changes in heritability across dog development.
Gnanadesikan et al. (Wed,) studied this question.