Behavioural manifestations of human-directed social motivation in dogs.

During domestication, dogs might have been selected for an increased motivation to engage socially with humans. A more nuanced conceptualization and evaluation of social motivation can improve our understanding of how domestication shaped dogs' psychology. We tested 104 dogs in a battery that assessed behaviours used as indicators of three aspects of social motivation: social orienting, reward, and maintaining. We aimed to test whether these behaviours indeed represented manifestations of the same construct, in which case we predicted a positive correlation between them. We found few significant correlations, some going in the opposite direction of our predictions. Our results might imply that the tests measured different traits, or that examined behaviours were not driven by the same motivational mechanism. Alternatively, the tests did not reveal sufficient individual variability or provide a clean measure, preventing us from finding existing associations. Moreover, it is possible that, contrary to our assumptions, social motivation is not consistent across contexts and is a context-specific trait instead. Future research should determine how to measure dogs' social motivation validly and reliably, re-examine assumptions regarding the motivational mechanisms underlying behaviours in commonly used tests and investigate interindividual differences in contextual plasticity regarding behavioural manifestations of social motivation.