Reports of intimate touch: erogenous zones and somatosensory cortical organization.

Introduction: Erogenous zones have paradoxical response properties, producing erotic feelings from body surfaces distant from the genitalia. Ramachandran has suggested an intriguing neuroscientific explanation for the distribution of erogenous zones, based on the arrangement of body parts (such as the adjacent positioning of the genitals and the feet) in primary somatosensory cortex (S1). The present study represents the first systematic survey of the magnitude of erotic sensations from various body parts, as well as the first empirical investigation of the S1 theory of erogenous zones, by analysis of whether evaluations of erogenous magnitude from adjacent S1 sites tend to correlate.

Methods: A sample of some 800 participants, primarily from the British Isles and Sub-Saharan Africa, completed a survey of 41 body parts, each rated for erogenous intensity.

Results: Ratings for the feet were surprisingly low. However, there were remarkable levels of correlation between ratings of intensity, regardless of the age, sexual orientation, nationality, race and, more surprisingly, the sex of our participant sample (R(2) values ranging between .90 and .98). Multiple regression and factor analysis investigated whether body parts nearby in S1 were significantly correlated.

Conclusion: The S1 hypothesis appears to lack support, because of the low level of foot ratings, the lack of inter-correlation between ratings for nearby S1 sites, and the previous literature suggesting that cortical stimulation of S1 does not appear to be erotogenic. The consistency across demographic variables is open to multiple interpretations. However, it may be that individual experience or cultural differences (a starting point for some accounts of erogenous zone distribution) are not substantial determining variables. Thus, while S1 does not appear to be the likely site that would support Ramachandran's neural body map proposal, we suggest that the origins of erogenous distribution may derive from a map located elsewhere in the brain.