Quantitative assessment of pleasant touch.

The hedonic attributes of tactile stimulation are important to one's quality of life, yet they have rarely been studied scientifically. The earliest experimental investigations suggested soft and smooth materials as pleasant, those that were stiff, rough, or coarse as unpleasant. More recent studies conducted by the authors and described herein obtained ratings of pleasantness of different textured materials stroked across the skin of multiple body sites at controlled velocities and forces of application. Statistically significant interactions between materials, sites, velocities, forces and subject sex attest to the complexity of the percept. Less pleasant percepts arose from stimuli that were rougher. However, the difficulty in making further general statements regarding hedonic touch raises questions as to whether the body surface can be mapped affectively in a meaningful manner with a single stimulus and indeed whether pleasantness-to-touch can be viewed as a unidimensional construct.