Auditory clicks distort perceived velocity but only when the system has to rely on extraretinal signals

Abstract

Previous work has found that repetitive auditory stimulation (click trains) increases the subjective velocity of subsequently presented moving stimuli. We ask whether the effect of click trains is stronger for retinal velocity signals (produced when the target moves across the retina) or for extraretinal velocity signals (produced during smooth pursuit eye movements, when target motion across the retina is limited). In Experiment 1, participants viewed leftward or rightward moving single dot targets, travelling at speeds from 7.5 to 17.5 deg/s. They estimated velocity at the end of each trial. Prior presentation of auditory click trains increased estimated velocity, but only in the pursuit condition, where estimates were based on extraretinal velocity signals. Experiment 2 generalized this result to vertical motion. Experiment 3 found that the effect of clicks during pursuit disappeared when participants tracked across a visually textured background that provided strong local motion cues. Together these results suggest that auditory click trains selectively affect extraretinal velocity signals. This novel finding suggests that the cross-modal integration required for auditory click trains to influence subjective velocity operates at later stages of processing.

Keywords:

• Velocity
• Smooth pursuit
• Eye movements
• Click trains
• Multimodal integration

View correction statement:

Corrigendum

A Leverhulme Trust Early Career Fellowship sponsored Alexis Makin. An Experimental Psychology Society Student Bursary sponsored Jayne Pickering, who collected data during summer 2012.

This article was originally published with errors. This version has been corrected. Please see corrigendum (http://dx.doi.org/10.1080/17470218.2013.837266).

Notes

¹ In all experiments the room was dimly lit, but was not in perfect darkness. Participants could easily see the edge of the screen and the wall behind. This could have provided opponent motion signals in the visual periphery during pursuit. However, in the pursuit trials of Experiment 3, the static background would produce much stronger retinal opponent motion signals in the foveal region and across the whole visual field.

² We cannot make any predictions regarding different click train frequencies based on the current data, but Penton-Voak et al. (1996) found no difference between 5- and 25-Hz click train frequencies on subjective duration, so it is possible that the frequency of clicks will have no effect on subjective velocity. Nevertheless, there are reported cases where click train frequency was consequential, for example Wearden et al. (1999) reported that 25-Hz clicks had greater effect than 5-Hz clicks, so this remains an open question.