RESUMEN
In human infants, the ability to show gaze alternations between an object of interest and another individual is considered fundamental to the development of complex social-cognitive abilities. Here we show that well-socialised dog puppies show gaze alternations in two contexts at an early age, 6-7 weeks. Thus, 69.4% of puppies in a novel object test and 45.59% of puppies during an unsolvable task alternated their gaze at least once between a person's face and the object. In both contexts, the frequency of gaze alternations was positively correlated with the duration of whimpering, supporting the communicative nature of puppies' gazing. Furthermore, the number of gaze alternations in the two contexts was correlated, indicating an underlying propensity for gazing at humans despite likely different motivations in the two contexts. Similar to humans, and unlike great apes or wolves, domestic dogs show gaze alternations from an early age if they are well-socialised. They appear to have a genetic preparedness to communicate with humans via gaze alternations early in ontogeny, but they may need close contact with humans for this ability to emerge, highlighting the interactive effects of domestication and environmental factors on behavioural development in dogs.
Asunto(s)
Fijación Ocular , Animales , Perros , Masculino , Femenino , Humanos , Comunicación Animal , Conducta SocialRESUMEN
The socialisation period in dog puppies is one of the most important periods determining behavioural development in dogs. Here, we aimed to test the effect of providing stimulation (beyond mere exposure) early during the socialisation period (approx. 3-6 weeks) on puppies' behaviour. Each of 12 litters (83 puppies) of various breeds was divided into a treatment and a control group. Between 3-6 weeks, the treatment group received age-appropriate "challenge" exercises (carefully graded noise exposure, novel objects, and problem-solving tasks) four times per week (total 12 times). The control group spent the same time with the trainer, who cuddled or played with the puppies. In a behaviour test at 6-7 weeks, two of four principal components, "social-startle" and "response to novelty", differed significantly between the groups. Treatment puppies were bolder towards the novel object, showed a reduced startle reaction, and recovered more quickly after a loud noise. Furthermore, they accomplished the problem-solving task faster and were more persistent during problem-solving than the control group. The control group showed a higher interest in a friendly stranger. It is a possibility that increased handling experienced by the control group had beneficial effects on their sociability. No long-term effects of the treatment were found, as determined by a validated dog personality questionnaire, available for 67 dogs at the age of six months. Likely, a continuation of the treatment over a longer time period would be necessary to obtain lasting effects, since the training took place only during the first third of the socialisation period.