Intra- and interactive touch on the face

Experiments were performed in which the subjective size of steel balls was judged by the method of absolute magnitude estimation (AME). The balls were rolled actively ("scripting") by the right index finger pad of the subject over the passively receiving areas of the face, namely the forehead, cheek and the vermilion border of the lower lip. These areas were stimulated on the subject's own person (intra-active touch), on another person's face (interactive touch) and by another person upon the face of the subject (interactive touch). Results indicate that size perception appears to be governed primarily by the mechanical characteristics of the stimuli, including the balls and the sites on the face. When the subject's finger was used to script upon another's face, there were significant differences among or between the sites. When another person scripted upon the subject's face there were no significant differences among any of the sites. The results are discussed considering mode of stimulation and tissue mechanics.