The only reason why people do believe in the myth is due to the fact that Dobermans are a bully breed. Its a way to explain their aggression or to even discourage getting one. According to a book entitled, The Pit Bull Placebo, the truth is that brain grows the same rate as any other dogs brain. Not only do Dobermans brains grow normally, but they never outgrow the skull unless suffering from some skeletal abnormality, which is rare.