# Behavioural Analysis of Dogs' Response to Threatening and Neutral Conspecific Video Stimuli +
## 4 Discussion
In line with this, future studies could test whether these behaviours are more likely to be elicited by an ambiguous situation, for example, when encountering an unfamiliar vs. a familiar social stimulus (thus, potentially carrying the proposed function of negotiation signals [19]; p. 163). Indeed, this would be in line with [PERSON] et al. [6] who found that displacement behaviours (especially head turning, nose licking and paw lifting) were exhibited more often when dogs encountered unfamiliar compared to familiar conspecifics. In both our previous studies with actual human experimenters and the present study, the neutral stimuli (an unfamiliar human approaching with a relaxed posture and a video of an unfamiliar dog standing and panting) elicited more displacement behaviours than the \"threatening one\". This may support the idea that it is the uncertainty of the situation which elicits these behaviours, which would hence have the function of conveying a \"non-conflict/peaceful\" intent. In this case, these behaviours should be exhibited more in such ambiguous scenarios, than, for example, when exposed to an overtly friendly approach. Future studies are required to further investigate the context, by, for example, changing the identity of the actor (familiar/non-familiar partner) and the social context (threatening, neutral, friendly and affiliative). One limitation of this study is the absence of physiological measures to monitor the stress response in the dogs tested. Previous research has identified displacement behaviours and facial expressions, putative appeasement signals, as indicators of the physiological stress response: yawning [34; 35; 36], lip licking [34; 35], manipulation/sniffing of the environment [17; 37]. The results from the current study do not align with this interpretation since, in this case, we would have expected them more in the threatening than in the neutral condition. Nevertheless, to further test this hypothesis, studies should include a condition presenting a non-socially relevant video/audio which may elicit a stress response in dogs and include physiological measures of arousal (hypothalamic pituitary adrenal axis activation) such as heart rate or cortisol to assess their association with the exhibition of behavioural variables [34]. The secondary aim of the present work was to investigate whether the visual component of the stimuli would elicit behavioural responses in dogs, thereby providing a tool for future studies. To control for the potential effect of the auditory component on the reaction of the dogs, the same visual stimuli (threatening and neutral) either paired with its natural audio (barking and panting) or paired with a socially non-relevant audio with the same sound features (Hz, amplitude and pattern) was presented. If behavioural responses were caused predominantly by the social auditory stimulus (see [27]), then a higher frequency/duration of behaviours with the original video (with natural sound pairing) than the videos with the artificial audio were expected. Dogs looked more at videos paired with natural sounds suggesting that they were more interested in a socially coherent than a non-coherent stimulus. However, aside from this, only a very limited effect of the audio type on the behavioural responses was found. An interaction between the condition and the audio type was found only for one behaviour, i.e., AU145--blinking: dogs blinked more when the neutral videos were paired with the natural sound but there was no difference in blink frequency during the threatening condition between the natural and artificial sounds. Furthermore, independently of the condition, dogs kept their ears in a flattened position (EAD103) more when the artificial audio was played compared to when the natural audio was played. Thus, taken together, the results suggest that although the natural pairing elicited more attention, dogs were not just responding to the socially relevant auditory stimuli (barking and panting).