| Popis: |
Performance in a simultaneous two‐frequency detection task was studied under monaural and dichotic conditions of signal presentation. In the basic task a 630‐Hz tone, a 1400‐Hz tone, neither tone, or both tones occurred with equal likelihood on an experimental trial. The observer had to specify which of these events had occured. Performance was examined: (a) when the signal could occur only in the right earphone channel, and (b) when the 630‐ and 1400‐Hz signals were confined, respectively, to the left and right earphone channels. Single‐frequency comparison conditions were also run. A performance decrement was observed in both of the two‐frequency conditions compared to the single‐frequency condition. However, there was no consistent difference between the monaural and dichotic two‐frequency conditions. An analysis of the conditional detection probabilities revealed the presence of a cross‐frequency interference effect on trials when a signal was present at the other frequency. This effect was sufficient to account for the differences between single‐frequency and two‐frequency detection performance. |
