Publications of József Topál

Dogs Identify Agents in Third-Party Interactions on the Basis of the Observed Degree of Contingency

To investigate whether dogs could recognize contingent reactivity as a marker of agents’ interaction, we performed an experiment in which dogs were presented with third-party contingent events. In the perfect-contingency condition, dogs were shown an unfamiliar self-propelled agent (SPA) that performed actions corresponding to audio clips of verbal commands played by a computer. In the high-but-imperfect-contingency condition, the SPA responded to the verbal commands on only two thirds of the trials; in the low-contingency condition, the SPA responded to the commands on only one third of the trials. In the test phase, the SPA approached one of two tennis balls, and then the dog was allowed to choose one of the balls. The proportion of trials on which a dog chose the object indicated by the SPA increased with the degree of contingency: Dogs chose the target object significantly above chance level only in the perfect-contingency condition. This finding suggests that dogs may use the degree of temporal contingency observed in third-party interactions as a cue to identify agents.

The order of ostensive and referential signals affects dogs’ responsiveness when interacting with a human

Ostensive signals preceding referential cues are crucial in communication-based human knowledge acquisition processes. Since dogs are sensitive to both human ostensive and referential signals, here we investigate whether they also take into account the order of these signals and, in an object-choice task, respond to human pointing more readily when it is preceded by an ostensive cue indicating communicative intent. Adult pet dogs (n = 75) of different breeds were presented with different sequences of a three-step human action. In the relevant sequence (RS) condition, subjects were presented with an ostensive attention getter (verbal addressing and eye contact), followed by referential pointing at one of two identical targets and then a non-ostensive attention getter (clapping of hands). In the irrelevant sequence (IS) condition, the order of attention getters was swapped. We found that dogs chose the target indicated by pointing more frequently in the RS as compared to the IS condition. While dogs selected randomly between the target locations in the IS condition, they performed significantly better than chance in the RS condition. Based on a further control experiment (n = 22), it seems that this effect is not driven by the aversive or irrelevant nature of the non-ostensive cue. This suggests that dogs are sensitive to the order of signal sequences, and the exploitation of human referential pointing depends on the behaviour pattern in which the informing cue is embedded.

What or where? The meaning of referential human pointing for dogs (Canis familiaris)

Dogs have a unique capacity to follow human pointing, and thus it is often assumed that they can comprehend the referential meaning of such signals. However, it is still unclear whether dogs perceive human directional gestures as signals referring to a target object (indicating what to manipulate) or a spatial cue (indicating where to do something). In the present study, we investigated which of these alternative interpretations may explain dogs’ responses to human pointing gestures in ostensive communicative and nonostensive cuing contexts. To test whether dogs select the cued object or the cued location, subjects were presented with 2 alternative object-choice trials. An experimenter first attracted the attention of the dog either by calling the dog’s name and looking at it (ostensive condition, n = 24) or by clapping the hands (nonostensive condition, n = 24) then pointed at 1 of 2 different toy objects. Subsequently, the experimenter switched the location of the 2 target objects in full view of the dogs by grasping the objects and making a 180° turn. Dogs were then allowed to choose between the 2 objects. In the ostensive condition, dogs showed a significant bias toward the cued location compared with the nonostensive condition in which they performed at chance. These results suggest that pointing refers to a direction or location for dogs, but only if they are addressed with ostensive cues that indicate the communicative intention of the signaler.