The use of a displacement device negatively affects the performance of dogs (Canis familiaris) in visible object displacement tasks

In what sense are dogs special? Canine cognition in comparative context

The great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. In this review, we seek to place our enhanced understanding of canine cognition into context. We argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenetically, as carnivoran and specifically a canid; ecologically, as social, cursorial hunters; and anthropogenically, as a domestic animal. A principled understanding of canine cognition should therefore involve comparing dogs' cognition with that of other carnivorans, other social hunters, and other domestic animals. This paper contrasts dog cognition with what is known about cognition in species that fit into these three categories, with a particular emphasis on wolves, cats, spotted hyenas, chimpanzees, dolphins, horses, and pigeons. We cover sensory cognition, physical cognition, spatial cognition, social cognition, and self-awareness. Although the comparisons are incomplete, because of the limited range of studies of some of the other relevant species, we conclude that dog cognition is influenced by the membership of all three of these groups, and taking all three groups into account, dog cognition does not look exceptional.

Metacognition in dogs: Do dogs know they could be wrong?

In the current study, we investigated the question of whether dogs were sensitive to the information that they themselves had or had not acquired. For this purpose, we conducted three consecutive experiments in which dogs had to find a reward that was hidden behind one of two V-shaped fences with a gap at the point of the V. This setup allowed us to distinguish between selecting one of the fences by walking around it and seeking additional information by checking through the gap in the fence. We varied whether dogs had visual access to the baiting procedure or not. In addition, we manipulated the type and quality of reward as well as the time delay between baiting and choosing to analyze if the dogs' searching behavior was affected. Our results were partly consistent with the findings of Call (Animal Cognition, 13 (5), 689-700, 2010) with great apes, on whose findings we based our experiments. We found that dogs checked more often through the corner of the V-shaped fence when they had not seen where the reward was hidden. Interestingly, dogs rewarded with toys selected the correct fence more often than dogs rewarded with food. Even though dogs' performance was not affected by the food quality condition, dogs were significantly faster in fetching a high-quality food reward as opposed to a low-quality food reward. When testing whether forgetting and checking would increase as a function of delay, we found that although dogs slightly decreased in their success in finding the food when time delays were longer, they were not more likely to check before choosing. We show that - similar to apes - dogs seek additional information in uncertain situations, but their behavior in uncertain situations is less flexible compared to great apes.

Does size really matter? Investigating cognitive differences in spatial memory ability based on size in domestic dogs

The study of canine cognition can be useful in understanding the selective pressures affecting cognitive abilities. Dogs have undergone intensive artificial selection yielding distinctive breeds, which differ both phenotypically and behaviorally and no other species has a wider range in brain size. As brain size has long been hypothesized to relate to cognitive capacity, this species offers a useful model to further explore this relationship. The influence of physical size on canine cognition has not been thoroughly addressed, despite the fact that large dogs are often perceived to be 'smarter' than small dogs. To date, this preconception has only recently been addressed and supported in one study comparing large and small dogs in a social cognition task, where large dogs outperformed small dogs in a pointing choice task. We assessed large and small dogs using a series of spatial cognition tasks and detected no differences between the two groups. Further research is needed to clarify why our results failed to compliment previous findings. It is possible that differences found in social cognition tasks may not be due to differences in size, rather they may be based on other factors such as methodology, prior training experience, or past experience with humans in general.

Global bias reliability in dogs (Canis familiaris)

Dogs enrolled in a previous study were assessed two years later for reliability of their local/global preference in a discrimination test with the same hierarchical stimuli used in the previous study (Experiment 1) and with a novel stimulus (Experiment 2). In Experiment 1, dogs easily re-learned to discriminate the positive stimulus; their individual global/local choices were stable compared to the previous study; and an overall clear global bias was found. In Experiment 2, dogs were slower in acquiring the initial discrimination task; the overall global bias disappeared; and, individually, dogs tended to make inverse choices compared to the original study. Spontaneous attention toward the test stimulus resembling the global features of the probe stimulus was the main factor affecting the likeliness of a global choice of our dogs, regardless of the type of experiment. However, attention to task-irrelevant elements increased at the expense of attention to the stimuli in the test phase of Experiment 2. Overall, the results suggest that the stability of global bias in dogs depends on the characteristics of the assessment contingencies, likely including the learning requirements of the tasks. Our results also clearly indicate that attention processes have a prominent role on dogs' global bias, in agreement with previous findings in humans and other species.

Now You See It, Now You Don’t

The cognitive ability of dogs can be assessed using tasks from the human developmental literature. A task that appears to have ecological relevance is the object-permanence task, in which performance hinges on understanding that an object continues to exist once it can no longer be seen. Although dogs are good at visible displacement tasks, in which an object disappears into a container, they can also understand an invisible displacement, in which the container holding the object is moved. Furthermore, we have found that dogs are able to show considerable memory for the invisibly displaced object. We have also found evidence for object permanence in dogs using the violation-of-expectancy procedure, in which subjects look longer at a stimulus that violates expectations (a screen that appears to pass through an object that has been placed behind the screen) than one that does not. Similarly, we have found that dogs look longer at an object that appears to have changed color or size after being placed behind a screen compared to an object that has not changed. Object-permanence tasks provide an ecologically relevant means of evaluating the cognitive development of dogs.