Free-ranging dogs are capable of comprehending complex human pointing cues

Dogs are the most common species to be found as pets and have been subjects of human curiosity leading to extensive research on their socialization with humans. One of the dominant themes in dog cognition pertains to their capacity of understanding and responding to human referential gestures. The remarkable socio-cognitive skills of pet dogs, while interacting with humans, is quite well established. However, studies regarding the free-ranging subpopulations are greatly lacking. Free-ranging dogs represent an ideal system to investigate interspecific communication with unfamiliar humans, nullifying any contribution of indirect conditioning. The interactions of these dogs with humans are quite complex and multidimensional. For the first time, we tested free-ranging dogs’ ability to understand relatively complex human referential gestures using dynamic and momentary distal pointing cues. We found that these dogs are capable of apprehending distal pointing cues from humans. However, approximately half of the population tested showed a lack of tendency to participate even after successful familiarization with the experimental set-up. A closer inspection revealed anxious behavioural states of the individuals were responsible for such an outcome. We assume that life experiences with humans probably shape personalities of free-ranging dogs, which in turn influence their responsiveness to human communicative gestures.

3.100, df = 2, p = 0.212), whereas the percentages were 38%, 32%, and 30% respectively for 1 4 6 the momentary distal cue condition (Goodness of fit χ 2 test: χ 2 = 7.000, df = 2, p = 0.705). We 1 4 7 found 17.5%, 27.5% and 55% of the dogs to be affiliative, neutral and anxious in the control were comparable within the test conditions, but it differed in the control condition. Dogs 1 5 0 showed higher anxious behavioural states compared to affiliation in the control condition emphasized the anxious behavioural responses and compared test and control dogs. We found 1 5 5 that dogs in the control condition were significantly more anxious than in the test conditions  We emphasized on the test conditions further, pooled the data and found a significant effect individuals that did not approach showed affiliative, neutral and anxious behavioural states 1 6 0 respectively, with the response levels being significantly different (Goodness of fit χ 2 test: χ 2 1 6 1 = 41.333, df = 2, p < 0.001, Fig 4). Fearful or anxious individuals showed higher 'no   Additionally, out of the individuals that followed pointing cues in the test conditions 1 6 6 (pooled), 88%, 80% and 64% displayed affiliative, neutral and anxious behaviours 1 6 7 respectively. The levels at which these responses were seen were comparable (Goodness of 1 6 8 fit χ 2 test: χ 2 = 3.117, df = 2, p = 0.21).

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(viii) Effect of sex, behavioural states and type of pointing cues on the approach response -1 7 0 GLM analysis revealed only a significant effect of anxious behavioural state on the approach 1 7 1 response (Table 1). 'No approach' was strongly predicted by anxious behavioural states of 1 7 2 individuals. We found no effect of sex and types of pointing cues. followed cues and rewarded in a preceding trial. We did not see any effect of the 'lack of   Our study showed that free-ranging dogs are capable of following complex pointing cues 1 9 0 from humans. Dogs that approached the set-up followed both the pointing cues at 1 9 1 significantly higher rates, suggesting their ability to understand complex human referential 1 9 2 gestures. Only half of the population tested approached the experimenter, which suggests that 1 9 3 the remaining dogs were more wary of humans and suggests the population-level perception 1 9 4 of humans by the free-ranging dogs. Anxious dogs were mostly reluctant to approach the 1 9 5 unfamiliar human experimenter even after succeeding in the familiarisation phase, whereas, 1 9 6 their neutral and affiliative counterparts showed significantly higher approach. The varying 1 9 7 responses in approach can be explained by dogs' lifetime experience (with unfamiliar 1 9 8 humans), differences in motivation to participate, and inability to understand distal pointing 1 9 9 cues. We nullify the second possibility as dogs that did not approach in the test or control expected not to be well fed (personal observation). We also discard the last possibility as our 2 0 3 findings clearly suggest that these dogs can indeed understand distal pointing cues. It is also 2 0 4 important to note that the approach rate was also 50% in the control condition where no cue  It was surprising to see the outcomes from comparisons between dynamic proximal, dynamic 2 1 3 distal and momentary distal cues, which highlighted a lower tendency of dogs to follow 2 1 4 dynamic proximal cues. Since the experimental design was comparable for all the cues, we 2 1 5 believe that the type of cue itself (dynamic proximal cue) had affected dogs' responses.

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Earlier we have mentioned the two different ways in which free-ranging dogs in India obtain 2 1 7 food from humans most of the time. While this has not been extensively tested, but it is likely 2 1 8 that dogs are more accustomed to humans throwing a piece of food away from themselves as 2 1 9 a response to begging, or to a human putting/dropping food on the ground and moving away. The complex pointing gestures used in the current experiments simulate these situations quite 2 2 1 closely. However, though the proximal pointing cue is considered to be a simpler cue to 2 2 2 follow from a completely anthropomorphic perspective to an untrained dog, this might be a 2 2 3 more "difficult" situation, with an unfamiliar human constantly pointing at the container, and to maintain a certain distance from unfamiliar humans and avoid making contact with them 2 2 6 37,38 . It is thus likely that a reduced perception of threat elicited higher response by the dogs to 2 2 7 the distal cues, though the proximal cue is likely to be more definitive and less ambiguous as 2 2 8 a signal. Gaze alternation has been suggested as an intentional and referential act in dog-human  This can be explained by the involvement of higher movements in the dynamic distal cue 2 3 3 conditions which might have influenced the dogs to alter their gaze accordingly.

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Interestingly, free-ranging dogs have recently been found to understand active and inactive adapted to using human-directed gazing and gaze alternations. Pet dogs have been found to 2 3 8 be deceived by incorrect or wrong cues 43-45 , but they also have some understanding of 2 3 9 human reliability 43,46,47 . In an earlier study, we reported the free-ranging dogs' ability to 2 4 0 adjust their point-following behaviour based on the reliability of the human experimenter 39 .

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Here, we found similar outcomes for the complex cues, in spite of the cues being more subtle 2 4 2 than the proximal one, further supporting and strengthening the earlier claim.

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This study confirms our earlier reports on free-ranging dogs' ability to understand human humans play a role, albeit inadvertently, in shaping the personalities of free-ranging dogs.

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This conjecture is supported by a recent study in which we observed that dogs respond conflict as well as provide insights into urban adaptation in general. We tested 160 adult free-ranging dogs in this study. All the dogs were randomly located on 2 6 2 the streets of Kanchrapara (22°94'41"N, 88°43'35"E), Kalyani (22°58'30"N, 88°26'04"E) and found such as market places, railway stations, bus stations and residential areas were 2 6 6 sampled. Adult dogs that seemed physically fit (in appearance, without any sign of injuries 2 6 7 and wounds) were considered for testing. We recorded coat colour, specific colour patches, 2 6 8 scar marks and approximate body size of the dogs to avoid re-testing. We confirmed the 2 6 9 sexes of the dogs by observing their genitals. Two experimenters, namely E1 and E2, were involved and played specific roles throughout 2 7 2 the study. E2 was consistent while four other people played the role of E1. We used opaque 2 7 3 plastic bowls (Volume = 500 ml), and cardboard pieces as their covers. Small pieces of raw 2 7 4 chicken (roughly 10 -12 g) were used as hidden food rewards. Here we provided adult free-2 7 5 ranging dogs with two types (momentary and dynamic) of distal pointing cues 10 to locate 2 7 6 hidden food rewards. Separate sets of dogs were tested using momentary and dynamic distal 2 7 7 cues.

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Experimenters walked on randomly selected streets of the study sites to locate solitary free- Free-ranging dogs in India are not habituated to getting food from covered plastic bowls. So, 2 8 4 this phase was carried out to familiarise them with the bowls used in the experimental set-up. cues) in the process. E1 showed a raw chicken piece to an individual dog and allowed to sniff it closely, then placed it inside an opaque plastic bowl and covered it with a cardboard. E1 2 8 8 placed the covered bowl on the ground at an approximate distance of 1.5 m from the dog and