'Improving one's touch' ... and more.

Gordon and Cooper (1975) have described an interesting tactile phenomenon. The orientation of undulations on the surface of an object can be detected more accurately when a person moves an intermediate paper over the surface than when the bare fingers are used. Counter to a prediction derived from Gordon and Cooper's explanation of their results, the present studies show that the apparent roughness of a surface increases when a similar manner of touching is used. The first two experiments confirm the latter observation. To explain the alteration in perceived roughness (and more tentatively, Gordon and Cooper's own findings), it is proposed that surface roughness (and undulations) are masked by shear forces applied to the skin. Two informal tests and a third experiment support this interpretation. Alternative explanations and a practical application for the blind are also considered. [ABSTRACT FROM AUTHOR]