Gap detection: two-channel detection of the missing event

The ability to detect gaps in continuous sinusoids was studied in both single- and two-channel tasks. From single-channel tasks, psychometric functions were obtained. Pulse and gap functions were found to be essentially parallel, with gap detection being 3–4 dB poorer than pulse detection. In two-channel tasks, two-channel detection of gap signal events produced a lower level of performance than two-channel detection of pulse signal events. However, in an unusual condition where a gap stimulus produced what sounded like a pulse to the observer, performance in two-channel gap detection and two-channel pulse detection was quite similar. This latter result suggests (1) gap stimuli enter the system as efficiently as pulse stimuli, and (2) it is the system’s inferior ability to process perceptual gaps which leads to the lower performance normally observed in two-channel gap detection. In a fourth two-channel task which required the observer to detect gap stimuli in one channel and pulse stimuli in the other, no detrimental effect on performance could be detected—a result illustrating the flexibility of the two-channel processing mechanism. Implications of the results for the INR model of two-channel processing are discussed. Subject Classification: [43]65.75, [43]65.58, [43]65.68.