Date Published: July 17, 2017
Publisher: Public Library of Science
Author(s): Debottam Bhattacharjee, Nikhil Dev N., Shreya Gupta, Shubhra Sau, Rohan Sarkar, Arpita Biswas, Arunita Banerjee, Daisy Babu, Diksha Mehta, Anindita Bhadra, Juliane Kaminski.
Differences in pet dogs’ and captive wolves’ ability to follow human communicative intents have led to the proposition of several hypotheses regarding the possession and development of social cognitive skills in dogs. It is possible that the social cognitive abilities of pet dogs are induced by indirect conditioning through living with humans, and studying free-ranging dogs can provide deeper insights into differentiating between innate abilities and conditioning in dogs. Free-ranging dogs are mostly scavengers, indirectly depending on humans for their sustenance. Humans can act both as food providers and as threats to these dogs, and thus understanding human gestures can be a survival need for the free-ranging dogs. We tested the responsiveness of such dogs in urban areas toward simple human pointing cues using dynamic proximal points. Our experiment showed that pups readily follow proximal pointing and exhibit weaker avoidance to humans, but stop doing so at the later stages of development. While juveniles showed frequent and prolonged gaze alternations, only adults adjusted their behaviour based on the reliability of the human experimenter after being rewarded. Thus free-ranging dogs show a tendency to respond to human pointing gestures, with a certain level of behavioural plasticity that allows learning from ontogenic experience.
Humans have domesticated several animal species over thousands of years, beginning with the dog . Generations of close association between humans and the various domesticated species has led to the development of certain degrees of communication and attachment with humans in these species. Several such species including goats, pigs, ferrets, horses, cats etc. have been shown to respond to human communicative intents [2–6]. However, probably due to high degree of bonding present between dogs and humans, the social cognition of dogs (Canis lupus familiaris) and their ability to interact with humans have made them one of the most extensively studied species in the recent past . Dogs are capable of interacting and establishing social bonds with humans, which are similar to human caregiver-infant relationships . It has even been suggested that dogs “need” to bond with humans, and the presence of a human can help reduce stress in dogs . Human interventions like positive reinforcement and affiliative interactions are expected to influence dog behaviour positively, thereby being important factors in the training of dogs by their handlers [10,11].
Our experiment revealed interesting differences in the tendencies of free-ranging dogs to follow simple human pointing gestures at different stages of their development, thereby suggesting a role of ontogeny in the development of social cognition in these dogs. In our study, pups were most responsive to the task, and also showed the highest ability to follow dynamic proximal pointing. The relatively lower response of pups in the control condition further strengthened the validity of this conclusion. Juveniles acted in an interesting way by responding to the task more in the control condition than the test, and failing to follow the point in most cases. Adults showed similar response levels in the test and control conditions, suggesting that their tendency to respond to the task did not depend on the presence of the cue. Though pups followed pointing more than juveniles, only the adults showed adjustment of the point-following behaviour, based on their immediate experience. When an adult dog followed the pointing cue and obtained food reward, it had a higher chance of following the cue in the next trial; suggesting a level of flexibility in their reliance on humans. Juveniles showed a marginal tendency to avoid non-reliable humans more, while pups showed a higher tendency to rely even on non-reliable humans, suggesting a weaker avoidance of humans and inability to adjust the response to pointing based on an immediate experience of interaction with humans.