Basal plasma oxytocin & fecal cortisol concentrations are highly heritable and associated with individual differences in behavior & cognition in dog puppies.

Oxytocin and cortisol are hormones that can influence cognition and behavior, but the relationships between endogenous concentrations and individual differences in cognitive and behavioral phenotypes remain poorly understood. Across mammals, oxytocin has important roles in diverse social behaviors, and in dogs, it has been implicated in human-oriented behaviors such as social gaze and point-following. Cortisol, an end-product of the hypothalamic-pituitary-adrenal (HPA) axis, is often studied in relation to temperament and emotional reactivity, but it is also known to modulate executive functions. In this study, we measured basal fecal cortisol (n = 247) and plasma oxytocin (n = 249) in dog puppies from a pedigreed population (Canine Companions ®). We collected cognitive and behavioral data from these subjects (n = 247), including measures of human-oriented social cognition, memory, inhibitory control, perceptual discriminations, and temperament. Oxytocin concentrations were estimated to be very highly heritable (h2 = 0.90-0.99) and cortisol concentrations were estimated to be moderately-highly heritable (h2 = 0.43-0.47). Bayesian mixed models controlling for relatedness revealed that oxytocin concentrations were positively associated with spatial working memory and displayed a negative quadratic relationship with behavioral laterality, but no credible associations were seen for social measures. Cortisol concentrations exhibited a negative linear relationship with performance on an inhibitory control task and a negative quadratic relationship with bold behavioral reactions to a novel object. Collectively, our results suggest that individual differences in oxytocin and cortisol concentrations are under strong genetic control in dogs and are associated with phenotypic variation in aspects of temperament, behavioral laterality, and executive function.

Dog cognitive development: a longitudinal study across the first 2 years of life.

While our understanding of adult dog cognition has grown considerably over the past 20 years, relatively little is known about the ontogeny of dog cognition. To assess the development and longitudinal stability of cognitive traits in dogs, we administered a battery of tasks to 160 candidate assistance dogs at 2 timepoints. The tasks were designed to measure diverse aspects of cognition, ranging from executive function (e.g., inhibitory control, reversal learning, memory) to sensory discrimination (e.g., vision, audition, olfaction) to social interaction with humans. Subjects first participated as 8-10-week-old puppies, and then were retested on the same tasks at ~ 21 months of age. With few exceptions, task performance improved with age, with the largest effects observed for measures of executive function and social gaze. Results also indicated that individual differences were both early emerging and enduring; for example, social attention to humans, use of human communicative signals, independent persistence at a problem, odor discrimination, and inhibitory control all exhibited moderate levels of rank-order stability between the two timepoints. Using multiple regression, we found that young adult performance on many cognitive tasks could be predicted from a set of cognitive measures collected in early development. Our findings contribute to knowledge about changes in dog cognition across early development as well as the origins and developmental stability of individual differences.

Early-emerging and highly heritable sensitivity to human communication in dogs.

Human cognition is believed to be unique in part because of early-emerging social skills for cooperative communication.1 Comparative studies show that at 2.5 years old, children reason about the physical world similarly to other great apes, yet already possess cognitive skills for cooperative communication far exceeding those in our closest primate relatives.2,3 A growing body of research indicates that domestic dogs exhibit functional similarities to human children in their sensitivity to cooperative-communicative acts. From early in development, dogs flexibly respond to diverse forms of cooperative gestures.4,5 Like human children, dogs are sensitive to ostensive signals marking gestures as communicative, as well as contextual factors needed for inferences about these communicative acts.6-8 However, key questions about potential biological bases for these abilities remain untested. To investigate their developmental and genetic origins, we tested 375 8-week-old dog puppies on a battery of social-cognitive measures. We hypothesized that if dogs' skills for cooperating with humans are biologically prepared, then they should emerge robustly in early development, not require extensive socialization or learning, and exhibit heritable variation. Puppies were highly skillful at using diverse human gestures, and we found no evidence that their performance required learning. Critically, over 40% of the variation in dogs' point-following abilities and attention to human faces was attributable to genetic factors. Our results suggest that these social skills in dogs emerge early in development and are under strong genetic control.

Cognitive characteristics of 8- to 10-week-old assistance dog puppies.

To characterize the early ontogeny of dog cognition, we tested 168 domestic dog, Canis familiaris, puppies (97 females, 71 males; mean age = 9.2 weeks) in a novel test battery based on previous tasks developed and employed with adolescent and adult dogs. Our sample consisted of Labrador retrievers, golden retrievers and Labrador × golden retriever crosses from 65 different litters at Canine Companions for Independence, an organization that breeds, trains and places assistance dogs for people with disabilities. Puppies participated in a 3-day cognitive battery that consisted of 14 tasks measuring different cognitive abilities and temperament traits such as executive function (e.g. inhibitory control, reversal learning, working memory), use of social cues, sensory discriminations and reactivity to and recovery from novel situations. At 8-10 weeks of age, and despite minimal experience with humans, puppies reliably used a variety of cooperative-communicative gestures from humans. Puppies accurately remembered the location of hidden food for delays of up to 20 s, and succeeded in a variety of visual, olfactory and auditory discrimination problems. They also showed some skill at executive function tasks requiring inhibitory control and reversal learning, although they scored lower on these tasks than is typical in adulthood. Taken together, our results confirm the early emergence of sensitivity to human communication in dogs and contextualize these skills within a broad array of other cognitive abilities measured at the same stage of ontogeny.

Predictive Models of Assistance Dog Training Outcomes Using the Canine Behavioral Assessment and Research Questionnaire and a Standardized Temperament Evaluation.

Assistance dogs can greatly improve the lives of people with disabilities. However, a large proportion of dogs bred and trained for this purpose are deemed unable to successfully fulfill the behavioral demands of this role. Often, this determination is not finalized until weeks or even months into training, when the dog is close to 2 years old. Thus, there is an urgent need to develop objective selection protocols that can identify dogs most and least likely to succeed, from early in the training process. We assessed the predictive validity of two candidate measures employed by Canine Companions for Independence (CCI), a national assistance dog organization headquartered in Santa Rosa, CA. For more than a decade, CCI has collected data on their population using the Canine Behavioral Assessment and Research Questionnaire (C-BARQ) and a standardized temperament assessment known internally as the In-For-Training (IFT) test, which is conducted at the beginning of professional training. Data from both measures were divided into independent training and test datasets, with the training data used for variable selection and cross-validation. We developed three predictive models in which we predicted success or release from the training program using C-BARQ scores (N = 3,569), IFT scores (N = 5,967), and a combination of scores from both instruments (N = 2,990). All three final models performed significantly better than the null expectation when applied to the test data, with overall accuracies ranging from 64 to 68%. Model predictions were most accurate for dogs predicted to have the lowest probability of success (ranging from 85 to 92% accurate for dogs in the lowest 10% of predicted probabilities), and moderately accurate for identifying the dogs most likely to succeed (ranging from 62 to 72% for dogs in the top 10% of predicted probabilities). Combining C-BARQ and IFT predictors into a single model did not improve overall accuracy, although it did improve accuracy for dogs in the lowest 20% of predicted probabilities. Our results suggest that both types of assessments have the potential to be used as powerful screening tools, thereby allowing more efficient allocation of resources in assistance dog selection and training.