Social Stimulation by the Owner Increases Dogs’ (Canis familiaris) Social Susceptibility in a Food Choice Task—The Possible Effect of Endogenous Oxytocin Release

SIMPLE SUMMARY: Intranasal administration of oxytocin has been proposed to be an effective way of improving several socio-cognitive skills in humans. There is evidence that dogs show human-analogue social behaviours and socio-cognitive capacities. Furthermore, recent studies have demonstrated that the oxytocin system is related to human-directed social behaviour in dogs. Some human studies suggest that pre-treatment with social stimuli (eye contact, touch) has similar behavioural effects because these cues stimulate oxytocin release. In the present study, we show that both social stimulation by the owner as well as intranasal oxytocin administration increases dogs’ social susceptibility in a food choice task. This means that dogs after both treatments (as compared to control conditions) were more prone to conforming to a human demonstrator’s counterproductive choice (smaller amount of food), giving up their natural preference. These results highlight important mechanisms of social tuning between dogs and humans. ABSTRACT: Recent evidence suggests a human-like susceptibility to social influence in dogs. For example, dogs tend to ignore their ‘natural’ preference for the larger amount of food after having seen a human’s explicit preference for a smaller quantity. However, it is still unclear whether this tendency to conform to the partner’s behaviour can be influenced by social stimuli and/or the neurohormone oxytocin as primers to prosocial predispositions. In Experiment I, eighty two dogs were tested using Prato-Previde et al.’s food quantity preference task. In Experiment I, we investigated in a 2 × 2 design how (i) a 10-minute-long social stimulation by the owner versus a socially ignoring pre-treatment as well as (ii) on-line ostensive communications versus no communication during task demonstration affect dogs’ (N = 82) choices in the abovementioned food choice task. Results indicate that the owners’ pre-treatment with social stimuli (eye contact, petting) increased dogs’ susceptibility to the experimenter’s food preference, but the salient ostensive addressing signals accompanying human demonstration masked this social priming effect. In Experiment II, N = 32 dogs from the subjects of Experiment I were retested after oxytocin (OT) or placebo (PL) pre-treatments. This experiment aimed to study whether intranasal administration of oxytocin as compared to placebo treatment would similarly increase dogs’ tendency to re-enact the human demonstrator’s counterproductive choice in the same task. Results showed an increased susceptibility to the human preference in the OT group, suggesting that both socially stimulating pre-treatment and the intranasal administration of oxytocin have similar priming effects on dogs’ social susceptibility.