Detection performance for short visual stimuli depends on the duration of co-occuring auditory stimuli

There is converging evidence that the duration of an auditory event can affect the perceived duration of a co-occurring visual event. When a brief visual stimulus is accompanied by a longer auditory stimulus, the perceived visual duration stretches. If this reflects a genuine sustain of visual stimulus perception, it should result in enhanced perception of non-temporal visual stimulus qualities. To test this hypothesis, in a temporal two-alternative forced choice task, 28 participants were asked to indicate whether a short (∼24 ms), peri-threshold, visual stimulus was presented in the first or in the second of two consecutive displays. Each display was accompanied by a sound of equal or longer duration (36, 48, 60, 72, 84, 96, 190 ms) than the visual stimulus. As a control condition, visual stimuli of different durations (matching auditory stimulus durations) were presented alone. We predicted that visual detection can improve as a function of sound duration. Moreover, if the expected cross-modal effect reflects sustained visual perception it should positively correlate with the improvement observed for genuinely longer visual stimuli. Results showed that detection sensitivity (d′) for the 24 ms visual stimulus was significantly enhanced when paired with longer auditory stimuli ranging from 60 to 96 ms duration. The visual detection performance dropped to baseline levels with 190 ms sounds. Crucially, the enhancement for auditory durations 60–96 ms significantly correlates with the d′ enhancement for visual stimuli lasting 60–96 ms in the control condition. We conclude that the duration of co-occurring auditory stimuli not only influences the perceived duration of visual stimuli but reflects a genuine sustain in visual perception.