A friend or an enemy? Dogs’ reaction to an unfamiliar person showing behavioural cues of threat and friendliness at different times

Abstract

Responsiveness of adult pet dogs ( Canis familiaris) to an unfamiliar human was observed in two studies. Subjects were faced with an approaching woman (Stranger) who showed definite signs of friendliness and threat during alternate approaches. Observations consisted of two episodes: the Stranger either approached the dog in normal speed of walk while talking to it and finally petted it gently (Friendly approach episode) or she moved slowly and haltingly and looked steadily into the eyes of the dog without any verbal communication (Threatening approach episode). In the first study 30 dogs of 19 different breeds were tested in the two episodes in a balanced sequential order. The dogs acted appropriately according to the different human behaviour cues. The order of the Friendly/Threatening approaches had no significant effect on the dogs’ responsivity. In the second experiment 60 dogs of three breed groups (20 Belgian shepherds, 20 retrievers and 20 sled dogs) were first ‘greeted friendly’ and then approached ‘threateningly’ by the same Stranger. Results show significant breed specific differences in the responsivity when dogs faced an apparent switch of the human behaviour cues. Compared to retrievers and sled dogs, Belgian shepherds more frequently changed their response, showing passive or active avoidance or sign of aggression when approached threateningly. While sex differences were not found, breed comparisons suggest that selective breeding (i.e. for hunting or shepherd work) influenced the dogs’ sensitivity to human social cues in different ways. Results also support the hypothesis that human influence (domestication) has led to extreme flexibility of the dogs’ situation-relevant behaviour while interacting with an unfamiliar human.