They found little difference between the wolves' and dogs' behavior during the test. However, when the stranger disappeared these behaviors barely appeared.The researchers also found species specific differences, as besides the domestication, the artificial selection and also rearing conditions markedly shaped the dog's behavior. This result is in line with earlier findings that dogs are generally more attracted towards humans from early puppyhood what might be caused by genetic differences between dogs and wolves. Wolves live in families, usually consisting a mating pair and their offspring of different ages. Presumably the common ancestor also lived in a similar complex social environment what might provide a good basis for developing abilities to easily integrate into human social groups.