The personality of the Doberman Pinscher is known to be unique. There is a great deal of scientific evidence that Doberman Pinschers have a number of stable psychological traits, such as certain personality factors and intelligence. As early as 1965, studies have shown that there are several broad behavioral traits that significantly predict behavior and are genetically determined. Subsequently, there have been numerous scientific attempts to quantify canine personality or temperament by using statistical techniques for assessing personality traits in humans. These studies often vary in terms of the personality factors they focus on and in terms of ranking breeds differently along these dimensions. 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.