Channels of Reception in Pitch Discrimination

Abstract

Pitch discrimination was studied in 4 normal hearing subjects monaurally, binaurally, and in a variety of other channels of reception. No difference exists in sensitivity between the two normal earn of a subject, nor is there a difference between the sensitivity of the monaural channels and the binaural channel if all are matched for loudness. Also bone conduction was found to yield essentially equal pitch DL's after loudness was matched. All channels, except successive interaural, are equivalent under matched conditions. Successive interaural channels (standard in the right, variable in the left, and vice versa) show some deterioration of sensitivity and some increase in variance which can be attributed to the monetary fluctuations of diplacusis. Similar fluctuations were found also with respect to a channel utilizing a monaural standard and a binaural variable stimulus, the two ears matched in loudness. Under these conditions, furthermore, a third pitch is sensed, a phenomenon we term “triplacusis.” The authors suggest an interpretation of diplacusis and triplacusis as interaural interactions. In cases of perceptive hearing loss, however, the channels are not usually equivalent in pitch discrimination even if matched for loudness. Evidently other principles must be sought for the pathological case.