DOGS OBEY BETTER TO GESTURAL THEN VOCAL STIMULI BY STRANGERS

When communicating with dogs, humans often combine verbal and gestural cues. Here we compared the relative relevance of gestural versus verbal stimuli in relation with the familiarity of the cue-giver. Fifteen water rescue dogs were asked to perform four actions (SIT, LIE DOWN, STAY and COME), by providing them only gestural, only verbal and contrasting stimuli (i.e. a gestural and a verbal stimulus indicating different actions). Each dog underwent the procedure twice, once with the owner and once with a stranger providing stimuli. Dogs’ responses to the presented stimuli were collected as a binomial variable (expressed / did not express the requested behavior); for the contrasting condition response to the gestural stimulus was arbitrarily considered as the requested one. When stimuli were provided by the owner, the highest probability of observing the requested behavior was observed in the gestural than vocal (P=0.020; adjusted P after Generalized Estimation Equations model) or contrasting (P<0.001) conditions; the lowest probability was observed in the vocal condition (vs. contrasting: P<0.001). With the stranger, the vocal condition showed a lower probability than the gestural (P<0.001) and contrasting (P=0.01) conditions. The probability of expressing the requested behavior was higher if the owner provided stimuli than if the stranger provided stimuli in the vocal (P<0.001) and contrasting conditions (P<0.001). Conclusion: the gestures of the handler and the stranger were both equally effective on dog responses, whereas vocal stimuli were more difficult to generalize.