Priming of lowpass-filtered speech affects response bias, not sensitivity, in a bandwidth discrimination task

Priming is demonstrated when prior information about the content of a distorted, filtered, or masked auditory message improves its clarity. The current experiment attempted to quantify aspects of priming by determining its effects on performance and bias in a lowpass-filter-cutoff frequency discrimination task. Nonsense sentences recorded by a female talker were sharply lowpass filtered at a nominal cutoff frequency (F) of 0.5 or 0.75 kHz or at a higher cutoff frequency (F + ΔF). The listeners' task was to determine which interval of a two-interval-forced-choice trial contained the nonsense sentence filtered with F + ΔF. On priming trials, the interval 1 sentence was displayed on a computer screen prior to the auditory portion of the trial. The prime markedly affected bias, increasing the number of correct and incorrect interval 1 responses but did not affect overall discrimination performance substantially. These findings were supported through a second experiment that required listeners to make confidence judgments. The paradigm has the potential to help quantify the limits of speech perception when uncertainty about the auditory message is removed.