Apple-and-pin drawings by blind novices show occluded features: region theory

Sighted children drawing an apple with a pin through it show the hidden parts of the pin. That is, not only is the pin shown running towards the apple and out the other side, it is also shown inside the apple, without a single break, and so the sketch depicts the occluded parts of the pin. Several investigators have offered theories of the observation. We report here on tangible raised-line drawings by young blind people who are novices at drawing. They also include occluded segments of the pin. To explain the drawings we use the John Willats region theory. In this account, enclosed regions represent the volumes of 3D objects. According to region theory, what is in the interior of an object should be shown in the drawing even if it cannot be seen or touched. As a result, since occluded parts of the pin are inside the apple, blind children, like sighted children, include them in their drawings. In region theory, for both the blind and the sighted, long lines on a 2D pictorial surface represent elongated objects in the scene and regions on the surface represent 3D objects and their contents. The basis of region theory may be that sensory information for pins and lines has high-frequency components, and for apples and regions has lower-frequency components.