Cooperative but Dependent–Functional Breed Selection in Dogs Influences Human-Directed Gazing in a Difficult Object-Manipulation Task.

Simple Summary: The main components of dogs' species-specific behavior are thought to be mainly influenced by domestication. This implies that these phenotypes are expected to be present almost uniformly across the vast number and variety of dogs. However, the evolution of dogs did not end with domestication, as humans subsequently selected them for distinctly different tasks and levels of interactivity with their handlers. We hypothesized that 'cooperative' dog breeds would also show higher levels of dependency toward humans in a difficult problem-solving task than those dogs that were selected for being independent problem solvers. Our target behavior was 'looking back at the human', which is a typical reaction of socialized dogs to a difficult task. Indeed, cooperative dogs performed more gaze alternations between the reward and the nearby humans, and they looked back more than the independent dog breeds did. Importantly, the results cannot be explained by different levels of persistence between the breed types. Functional selection in the recent past of dogs can be considered as an excellent basis for biologically relevant explanations for the breed-level variability in dog behavior. It is still largely unknown to what extent domestication, ancestry, or recent functional selection are responsible for the behavioral differences in whether dogs look back to a human when presented with a difficult task. Here, we tested whether this ubiquitous human-related response of companion dogs would appear differently in subjects that were selected for either cooperative or independent work tasks. We tested N = 71 dogs from 18 cooperative and 18 independent breeds. Subjects learned in a five-trial warming-up phase that they could easily obtain the reward from a container. In trial six, the reward became impossible to take out from the locked container. When the task was easy, both breed groups behaved similarly, and their readiness to approach the container did not differ between the last 'solvable' and the subsequent 'unsolvable' trial. Task focus, looking at the container, touching the container for the first time, or interacting with the container with a paw or nose did not differ between the breed groups, indicating that their persistence in problem solving was similar. However, in the 'unsolvable' trial, cooperative dogs alternated their gaze more often between the container and the humans than the independent dogs did. The frequency of looking back was also higher in cooperative dogs than in the independent breeds. These are the first empirical results that suggest, in a balanced, representative sample of breeds, that the selection for different levels of cooperativity in working dogs could also affect their human-dependent behavior in a generic problem-solving situation. [ABSTRACT FROM AUTHOR]