UNIDIMENSIONAL AND MULTIDIMENSIONAL IDENTIFICATION OF RISE-TIME, SPECTRAL SLOPE, AND CUTOFF FREQUENCY

Absolute identification of rise time, spectral slope, and cutoff frequ ency was evaluated using complex tones comprising the first 40 harmoni cs of 200 Hz. Ranges of each dimension were restricted to those with r elevance to natural music and speech. Baseline unidimensional fixed-ba ckground tasks yielded 1.5-2.0 bits of information, indicating that li steners could consistently identify at least three to four categories per dimension. Fixed-and roved-background information transfers implie d rise time was perceptually separable from the other dimensions. Spec tral slope and cutoff frequency displayed substantial integrality (rat ios of fixed-background to roved-background information transfers of 1 .08-5.03), but the extent decreased with experience (retest ratios of 1.03-2.64). Stimulus combinations that maximized differences in high-f requency spectral regions were associated with increased information t ransfer and greater separability, suggesting a functional role for ''s harpness'' in timbre identifications. Total multidimensional informati on transfer was closely approximated by the sum of the corresponding u nidimensional roved-background values, supporting both the general add itivity of information transfer and the feasibility of using unidimens ional roved-background tasks to estimate multidimensional resolution e fficiently.