Conditioning in the unattended left ear.

Two experiments demonstrated that a conditioned emotional response can both be established and arouse responses without awareness in a dichotic paradigm. Right handed male subjects performed a complex verbal task presented to the right ear, while patterns of musical notes were presented to the left ear. For experimental subjects, one of the patterns was always followed by an aversive noise in the left ear; the noises were presented at random times to control subjects. In Study 1, latency of skin potential response to the noise decreased among experimental subjects relative to control subjects, indicating that the critical tone pattern was acting as a CS. Subject awareness was determined through both recall and recognition procedures, and only unaware subjects were used. Study 2 demonstrated the effect more powerfully by showing conditioned responses among experimental subjects on interpolated CS-alone trials and a lack of reportable awareness among all subjects.