Shapiro, although not presenting a comprehensive theory of OCPD, discussed what he saw as three of its primary characteristics. The first characteristic was a rigid, intense, sharply focused style of thinking. Shapiro found compulsives to have a “stimulus-bound” quality to their cognition, comparable in certain ways to that of brain-damaged people. By this, he meant that they are continually attentive and concentrating and rarely seem to just let their attention wander. Thus, they tend to be good at detailed, technical tasks, but are poor at discerning more global, impressionistic qualities of things, such as the tone of a social gathering. Shapiro referred to compulsives as having “active inattention.” They are easily distracted and disturbed by new information or external events outside their narrow range of focus, and they actively attempt to keep this distraction from occurring. As another consequence of this, they are rarely surprised.

The second characteristic Shapiro discussed is the distortion in the obsessive–compulsive’s sense of autonomy. Unlike normal self-direction based on volition and choice, the compulsive deliberately and purposefully self-directs each action. Thus, the compulsive exerts a continuous willful pressure and direction on himself as if by an “overseer” and even exerts “an effort to direct his own wants and emotions at will” (Shapiro, 1965, pp. 36–37). The fundamental aspect of the compulsive’s experience is the thought, “I should.” Compulsives experience any relaxation of deliberateness or purposeful activity as improper and unsafe. They invoke morality, logic, social custom, propriety, family rules, and past behavior in similar situations to establish what the “should” is in a given situation, and then act accordingly.