the contour of a side view of a person's nose. Thus, it can be relatively easy to draw this contour using a raised-like drawing kit. It may be quite different and more difficult, however, to feel a raised line on a surface and ascertain what the line represents. Millar proposes that recognition of factual representations is indirect, and depends upon the nature of haptic representation. That is, for Millar, haptic representation is based on action plans and recognition is a function of retrieval cues.
Action often serves perception in touch, and Millar has cleverly stressed a way this could aid representation. There are numerous theoretical precedents for the idea that we code patterns in terms of representations of movement patterns. Piaget and Inhelder ( 1956) have argued that "haptic images" depend upon movement schemas. Thus, the image one constructs of a triangle depends on the movements used to explore that shape. Also, we have the observation of the aphasic with alexia that is unable to read a simple word (see Heller, 1985; Hulme, 1979). This individual recognized the word after tracing its outline with his finger. This is an additional indication of motoric coding of form. Millar's chapter ties together a lot of loose threads in the haptic literature.
Heller M. A. ( 1985). "Tactual perception of embossed Morse code and braille: The alliance of vision and touch". Perception, 14, 563-570.
Piaget J., & Inhelder B. ( 1956). The child's conception of space. London: Routledge & Kegan Paul.
Warren D. H. ( 1978). "Perception by the blind". In E. C. Cartererie Carterette & M. P. Friedman (Eds.), Handbook of perception. New York: Academic Press.