Assessment of dogs behaviour in response to sounds with negative emotional valence

Sounds can elicit emotional reactions and behavioural reactions in dogs. Yet, the characteristics of sounds in relation to their ability to evoke emotions, and the associated behavioural manifestations, have been scarcely explored. The aim of this thesis was to develop a procedure to assess dogs behavioural responses to sounds with presumptive negative emotional valence. Two experimental procedures were designed, in order to 1) prove the negative valence of sounds and 2) identify the behavioural response elicited by these stimuli. To validate the negative valence of sounds, 29 companion dogs took part in a playback experiment, during which they were exposed to presumptive negative and neutral sound stimuli, while approaching a bowl containing food. When negative sound stimuli were being presented, the dogs’ latency of approach to food increased compared to baseline conditions, suggesting that the sounds did negatively affect dogs’ emotional state. To further validate these acoustic stimuli and allow the identification of behaviours typical of the negative emotional response, 30 additional subjects took part in a playback preference test which was designed to allow dogs to manifest freely their behaviour while also being given the opportunity to express a preference. A room was split in two exact halves and subjects were exposed to a sound (negative or neutral, depending on the condition) whenever entering the room-side associated with the sound-condition. Dogs spent more time in the silent room-side, avoiding the side with negative sound stimuli, while no relevant choice difference was observed with playback of neutral sound stimuli. This further supports the ability of the chosen sounds to evoke a negative emotional state. The preference method like the one proposed by the two-side room test, has never been used for the investigation of emotions elicited by acoustic stimuli in dogs. Therefore, the scientific procedures used in these experiments receive validation and lay the groundwork to continue further research which will aim at determining reliable behavioural indicators for negative emotions in dogs evoked by acoustic stimuli.