Functional Asymmetry of the Brain in Dichotic Listening!

Most of the studies I will be describing have been done with normal subjects, but I want first to review briefly some clinical studies which provide a background for the normal data. This work originated at the Montreal Neurological Institute while I was doing research, with Dr. Brenda Milner, on the functional differentiation of the right and left temporal lobes. One of the tests employed in investigating deficits associated with temporal-lobe lesions was the Broadbent (1954) technique. Two different digits are presented simultaneously to the two ears through earphones, one digit to the left ear, the other to the right ear. Usually, three such pairs are presented in rapid succession, and at the end of the six digits, the subject is asked to report all the numbers he heard, in any order he likes. The term II dichotic" has come into use to describe the simultaneous presentation of different stimuli to the two ears.