Better discrimination of small changes in commonly encountered than in less commonly encountered auditory stimuli

Results from 3 auditory tasks revealed that small changes made in stimuli commonly encountered in everyday life are more easily discriminated than are the same changes made in stimuli not as commonly encountered. The tasks required discrimination of a frequency difference in 1 tone of 6-tone chords or nonchords, discrimination of a duration difference in 1 note of common tunes or nontunes, and discrimination of the deletion of a band of frequencies from speech sounds played forward or backward. Different crews of college-aged listeners served in the different tasks. If future research shows this difference in discriminability to be a general property of commonly encountered stimuli--attributable to a difference in the way they are processed in the nervous system--then discrimination tests of this sort could become useful for assessing whether stimuli have made the transition from one form of processing to the other.