Absolute pitch and sex effect event-related potential activity for a melodic interval discrimination task

Absolute pitch is a special ability which allows for special perceptual/cognitive strategies. Studies have shown differences in event-related scalp potentials between absolute-pitch (AP) and relative-pitch (RP) subjects of equal musical training. In this study, highly trained musicians (15 females/15 males) performed a melodic interval discrimination task, using intervals on-pitch in equal-tempered tuning (A4 = 440 Hz) and tuned a half-semitone sharp. Subjects identified target intervals (probability 0.2) in a series of 400 randomly transposed intervals. AP subjects were expected to perform differently across intonation conditions, whereas RP subjects were not. Event-related potentials (ERPs) were recorded from three midline sites and two lateral sites. ERPs were analyzed by principal component analysis of variance. Sex was also considered as an independent subject variable. Performance was not significantly different either by absolute pitch or sex. Reaction times did not reveal any significant interactions involving AP or sex, but showed a significant effect by response type (target/nontarget). Strong P3 activity appeared to the target melodic intervals regardless of subject group or intonation. PCA factors with maxima at 352, 511, and 709 ms were sensitive to task relevance. Males showed greater positivity than females along the midline. A significant intonation by response type by sex interaction indicated a greater spread of values for females than males, and greater similarity in response by sex for the sharp than the on-pitch intervals. AP subjects showed reduced P3 activity along the midline, but increased over lateral sites. In a difficult musical task, the ERPs were sensitive to the sex of the listeners, as well as to whether they had absolute pitch.