Intuitive anatomy: Distortions of conceptual knowledge of hand structure.

Knowledge of the spatial layout of bodies is mediated by a representation called the body structural description, damage to which results in the condition of autotopagnosia in which patients are impaired in judgments about the location and configuration of body parts. While a large literature has investigated disruption of the body structural description, little research has examined its accuracy in healthy individuals. I show that people have systematically distorted knowledge of the configuration of hands. Participants judged the location of their knuckles (i.e., the metacarpophalangeal joint) by pointing with a baton on their palm. Participants showed clear distal biases, judging their knuckles as farther forward in the hand than they actually are for all fingers except the thumb. This effect appeared both when participants localized the knuckles of their own hand and another person's hand. These results suggest that intuitive beliefs about body form are systematically distorted.