The breed standard describes the Dobermann as a dog of medium size that is also strong and muscularly built. In order to be eligible to meet these standards, the body of the Dobermann should appear to be almost square. One such study found that Doberman Pinschers, compared to other breeds, rank high in playfulness, average in curiosity/fearlessness, low on aggressiveness, and low on sociability. Another such study ranked Doberman Pinschers low on reactivity/surgence and high on aggression/disagreeableness and openness/trainability.