No evidence of tactile distance anisotropy on the belly

The perceived distance between two touches has been found to be larger for pairs of stimuli oriented across the width of the body than along the length of the body, for several body parts. Nevertheless, the magnitude of such biases varies from place to place, suggesting systematically different distortions of tactile space across the body. Several recent studies have investigated perceived tactile distance on the belly as an implicit measure of body perception in clinical conditions including anorexia nervosa and obesity. In this study, we investigated whether there is an anisotropy of perceived tactile distance on the belly in a sample of adult women. Participants made verbal estimates of the perceived distance between pairs of touches oriented either across body width or along body length on the belly and the dorsum of the left hand. Consistent with previous results, a large anisotropy was apparent on the hand, with across stimuli perceived as larger than along stimuli. In contrast, no such bias was apparent on the belly. These results provide further evidence that anisotropies of perceived tactile distance vary systematically across the body and suggest that there is no anisotropy at all on the belly in healthy women.