Media release

From: The Royal Society

Dogs exhibit multiple personalities, functions, and cognitive abilities that can surpass those of non-human primates. We tested if relative endocranial volume (a proxy for brain size) is related to a dog's function and personality. We find that companionship dogs (toy breeds) have the largest relative “brain sizes”, while working dogs, known for complex human-assistance skills, have the smallest "brain sizes", although they possess higher cognitive abilities. Endocranial volume increases as dogs are more fearful or aggressive, and when they display more attention-seeking, excitability, and separation anxiety. In contrast, endocranial volume decreases with dog trainability, and appears unrelated to cooperative behaviour.