Oral Two-Point Discrimination: Further Evidence Of Asymmetry On Right And Left Sides Of Selected Oral Structures
2-point discrimination thresholds were established on 13 test sites (the midline, right, and left sides of the upper lip, lower lip, tongue tip, and tongue dorsum, and on the finger tip) in each of 14 Ss. A total of 10 thresholds, 5 ascending and 5 descending, were obtained at each site. It was found that all Ss exhibited evidence of asymmetry in their 2-point limen values between the right and left sides of at least one of the 4 oral structures tested. The results provide further support for McCall and Cunningham's (1971) proposed theory of “sensory sidedness” as a normal neurological phenomenon of the tactile sensory system.