Mariana Bentosela

Breed differences in dogs’ (Canis familiaris) gaze to the human face

Domestic dogs (Canis familiaris) have been submitted to a vast process of artificial selection and to date, there are hundreds of breeds that differ in their physical and behavioral features. In addition, dogs possess important skills to communicate with humans. Previous evidence indicates that those abilities are related to the domestication process and are modulated by instrumental learning processes. Very few studies, however, have evaluated breed differences in the use and learning of interspecific communicative responses. In Study 1 Retrievers, German Shepherds and Poodles were compared in the acquisition and extinction of their gaze toward the human face, in a conflict situation involving food within sight but out of reach. The groups did not differ in the acquisition of the response, but throughout the extinction phase Retrievers gazed to the human significantly more than the other groups. In Study 2, similar results were obtained in a test without any previous explicit training. These results suggest that these three major popular breeds differ in gazing to humans in a communicative situation.

Administration of corticosterone after the first downshift trial enhances consummatory successive negative contrast

Rats given access to a 32% sucrose solution and then downshifted to a 4% solution exhibit less contact with the sipper tube than unshifted controls always given access to 4% solution. This phenomenon, called consummatory successive negative contrast, was facilitated in Experiment 1 by a post-trial injection of corticosterone (3 mg/kg) administered immediately after the first downshift trial. Experiment 2 demonstrated that this facilitatory effect of post-trial corticosterone does not occur when administered 3 hr after the first downshift trial. These results support the hypothesis that corticosterone strengthens an aversive emotional component elicited by the surprising downshift in reward magnitude during the initial downshift trial.

Incentive Contrast in Domestic Dogs (Canis familiaris)

Dogs (Canis familiaris) trained to receive a preferred food (dry beef liver) from an experimenter learned to maintain a longer gaze on the experimenter than dogs receiving a less preferred food (dog pellets). Dogs downshifted from dry liver to pellets rejected food more frequently than nonshifted controls. Gaze duration also decreased in downshifted dogs below the level of a group always reinforced with pellets. In addition, downshifted dogs tended to move away from the experimenter, adopting a lying down posture. This phenomenon, called successive negative contrast, has been described in analogous experiments with a variety of mammalian species, but has failed to occur in similar experiments with nonmammalian vertebrates. Unlike similar previous observations, the present data were obtained in an environment involving interspecific communication.

Communication between domestic dogs and humans: effects of shelter housing upon the gaze to the human

It is widely known that gaze plays an essential role in communicative interactions. Domestic dogs tend to look at the human face in situations of conflict and uncertainty. This study compares the gaze of shelter and pet dogs during acquisition and extinction phases in a situation involving a reward in sight but out of reach. Even though no significant differences between the groups were recorded during acquisition, gaze duration decreased in both groups during extinction, with shelter dogs showing a significant shorter duration. This could be related to their different living conditions and to the fact that through their ordinary everyday interactions, pet dogs have more opportunities to learn to persist in their communicative responses when they do not get what they want. These results highlight the relevance of learning experiences during ontogeny, which would therefore modulate communicative responses.

Dogs’ Eavesdropping from People’s Reactions in Third Party Interactions

Eavesdropping involves the acquisition of information from third-party interactions, and can serve to indirectly attribute reputation to individuals. There is evidence on eavesdropping in dogs, indicating that they can develop a preference for people based on their cooperativeness towards others. In this study, we tested dogs’ eavesdropping abilities one step further. In a first experiment, dogs could choose between cooperative demonstrators (the donors) who always gave food to an approaching third person (the beggar); here, the only difference between donors was whether they received positive or negative reactions from the beggar (through verbal and gestural means). Results showed that dogs preferentially approached the donor who had received positive reactions from the beggar. By contrast, two different conditions showed that neither the beggar’s body gestures nor the verbal component of the interaction on their own were sufficient to affect the dogs’ preferences. We also ran two further experiments to test for the possibility of dogs’ choices being driven by local enhancement. When the donors switched places before the choice, dogs chose at random. Similarly, in a nonsocial condition in which donors were replaced by platforms, subjects chose at chance levels. We conclude that dogs’ nonrandom choices in the present protocol relied on the simultaneous presence of multiple cues, such as the place where donors stood and several features of the beggar’s behavior (gestural and verbal reactions, and eating behavior). Nonetheless, we did not find conclusive evidence that dogs discriminated the donors by their physical features, which is a prerequisite of reputation attribution.

Dog’s Discrimination of Human Selfish and Generous Attitudes: The Role of Individual Recognition, Experience, and Experimenters’ Gender

Discrimination of and memory for others’ generous and selfish behaviors could be adaptive abilities in social animals. Dogs have seemingly expressed such skills in both direct and indirect interactions with humans. However, recent studies suggest that their capacity may rely on cues other than people’s individual characteristics, such as the place where the person stands. Thus, the conditions under which dogs recognize individual humans when solving cooperative tasks still remains unclear. With the aim of contributing to this problem, we made dogs interact with two human experimenters, one generous (pointed towards the food, gave ostensive cues, and allowed the dog to eat it) and the other selfish (pointed towards the food, but ate it before the dog could have it). Then subjects could choose between them (studies 1-3). In study 1, dogs took several training trials to learn the discrimination between the generous and the selfish experimenters when both were of the same gender. In study 2, the discrimination was learned faster when the experimenters were of different gender as evidenced both by dogs’ latencies to approach the bowl in training trials as well as by their choices in preference tests. Nevertheless, dogs did not get confused by gender when the experimenters were changed in between the training and the choice phase in study 3. We conclude that dogs spontaneously used human gender as a cue to discriminate between more and less cooperative experimenters. They also relied on some other personal feature which let them avoid being confused by gender when demonstrators were changed. We discuss these results in terms of dogs’ ability to recognize individuals and the potential advantage of this skill for their lives in human environments.

Frustration Behaviors in Domestic Dogs

During extinction a previously learned behavior stops being reinforced. In addition to the decrease in the rate of the instrumental response, it produces an aversive emotional state known as frustration. This state can be assimilated with the fear reactions that occur after aversive stimuli are introduced at both the physiological and behavioral levels. This study evaluated frustration reactions of domestic dogs (Canis familiaris) during a communicative situation involving interactions with a human. The task included the reinforcement and extinction of the gaze response toward the experimenters face when the dogs tried to obtain inaccessible food. The dogs frustration reactions during extinction involved an increase in withdrawal and side orientation to the location of the human as well as lying down, ambulation, sniffing, and vocalizations compared with the last acquisition trial. These results are especially relevant for domestic dog training situations in which the extinction technique is commonly used to discourage undesirable behaviors.

Direct reciprocity in animals: The roles of bonding and affective processes

The presence of direct reciprocity in animals is a debated topic, because, despite its evolutionary plausibility, it is believed to be uncommon. Some authors claim that stable reciprocal exchanges require sophisticated cognition which has acted as a constraint on its evolution across species. In contrast, a more recent trend of research has focused on the possibility that direct reciprocity occurs within long-term bonds and relies on simple as well as more complex affective mechanisms such as emotional book-keeping, rudimentary and higher forms of empathy, and inequity aversion, among others. First, we present evidence supporting the occurrence of long-term reciprocity in the context of existing bonds in social birds and mammals. Second, we discuss the evidence for affective responses which, modulated by bonding, may underlie altruistic behaviours in different species. We conclude that the mechanisms that may underlie reciprocal exchanges are diverse, and that some act in interaction with bonding processes. From simple associative learning in social contexts, through emotional contagion and behavioural mimicry, to empathy and a sense of fairness, widespread and diverse social affective mechanisms may explain why direct reciprocity may not be a rare phenomenon among social vertebrates.

Are animal-assisted activity dogs different from pet dogs? A comparison of their sociocognitive abilities

ABSTRACT Animal‐assisted activities (AAAs) refer to a variety of interactions between animals and humans, intended to improve peoples well‐being providing recreational or educational opportunities. Domestic dogs are one of the most commonly used animals for these kinds of interventions, given their trainability and the positive effects of dog‐human interactions. Nevertheless, the selection of participating animals is mainly unsystematic, and training is not required for dogs to take part in AAAs. Previous studies suggest that high sociability as well as reduced fear and aggression are desirable traits in AAA dogs. Yet, to our knowledge, there are no previous studies assessing the specific characteristics of dogs participating in AAAs. The aim of this study was to compare the performance of AAA and pet dogs (PDs) that live in the same household but do not participate in AAAs. We assessed 17 dogs (9 participating in AAAs in hospital settings and 8 pets living in the same household–control group) with a test battery comprising 3 behavioral tasks (sociability test, gazing test, and A‐not‐B task), and owner‐rated questionnaires (Dog Impulsivity Assessment Scale [DIAS] and 4 subscales: trainability, fear to strangers, nonsocial fear, and attachment/attention seeking of the Canine Behavioral Assessment and Research Questionnaire [C‐BARQ]). Results of the gazing test indicate that, when dogs were not reinforced for looking at the human face, AAA dogs gazed longer at an unknown experimenter than PDs. Therefore, they showed an increased tendency to gaze at humans and persist on this communicative attempt when this response was not successful. Additionally, according to the DIAS score, AAA dogs would be less impulsive than the control group. No significant differences were found on the A‐not‐B task, the sociability test, or the C‐BARQ. In conclusion, since these AAA dogs had not undergone specific training, the effects observed in the present work may be attributed, at least partially, to the learning experiences they had during AAA work. Overall, it would be important to take into account these characteristics for both the selection and training of these animals.