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 c ommonly encountered in everyday life are more easily discriminated than are the same changes made in stimuli not as commonly encountered. The tasks re quired discrimination of a frequency difference in 1 tone of 6-tone chords or nonchords, discrimination of a duration difference in 1 note of common t unes or nontunes, and discrimination of the deletion of a band of frequenci es from speech sounds prayed forward or backward. Different crews of colleg e-aged listeners served in the different tasks. Lf future research shows th is difference in discriminability to be a general property of commonly enco untered stimuli-attributable to a difference in the way they are processed in the nervous system-then discrimination tests of this sort could become u seful for assessing whether stimuli have made the transition from one form of processing to the other.