Abstract:
When presented with ambiguous information, happy people are more likely to make optimistic judgements while depressed and anxious people are more likely to make pessimistic judgements. Judgement bias tasks are a modern but well-established way to exploit the intrinsic interaction between emotion and cognition to infer the emotional states of non-human animals. This study uses a version of the judgement bias test to measure whether the affective states of domestic dogs (canis familiaris) can be altered with emotionally expressive music. Ten dog owners were recruited through the University of Auckland’s Clever Canine Lab. The dogs were trained in a basic spatial discrimination task where they learnt to quickly approach a bowl placed in a positive (reinforced) location, and ignore a bowl placed in a negative (unreinforced) location. The dogs were then played musical excerpts suited to evoke either fear or joy, before the bowl was placed at one of a series of intermediate ambiguous locations to measure how the music affected the dogs’ relative optimism biases. The dogs were significantly faster to approach the ambiguous probe nearest to the reinforced location when they heard joy music compared to fear music (z = -1.988, p =.049, r = 0.44). The results suggest music has the power to elicit affective states in dogs similarly to humans, providing the foundations for a larger research effort, which could have substantial implications for animal welfare, while also raising deeper questions about the nature and evolution of music.