Behavioural and electrodermal measures of lateralization for music perception in musicians and nonmusicians

Two groups of students, musicians and nonmusicians were tested on a dichotic listening forced choice recognition task with concurrent recording of bilateral electrodermal activity. Stimuli were excerpts of Bach 4-part chorales; probes were the soprano, bass, harmony or the chorale excerpt, with or without changed notes. Laterality effects in recognition and the GSR were obtained only in musicians as a function of the complexity of the task. It was concluded that styles of information processing assumed by the hemispheres are the consequence of an interaction between the stimulus and the state of the organism at the moment, such that the direction of laterality can change within a subject performing the same task depending upon its perceptual demand.