Abstract
It has recently been shown that spatially uninformative sounds can cause a visual stimulus to pop-out from an array of similar distractor stimuli when that sound is presented near simultaneously with a feature change in the visual stimulus. Until now, this effect has only been shown for stimuli that remain at a fixed position. Here we extend these results by showing that auditory stimuli can also improve the detectability of visual stimulus features related to motion. To accomplish this we presented moving visual stimuli (small dots) on a computer screen. At a random moment during a trial, one of these stimuli could abruptly start moving in an orthogonal direction. Participants' task was to indicate whether such a change in direction had occurred or not by making a corresponding button press. When a sound (a short 1000Hz tone pip) was presented simultaneously with a motion change, participants were able to detect this motion direction change among a significantly higher number of distractor stimuli, compared to when the sound was absent. When the number of distractor stimuli was kept constant, detection accuracy was significantly higher when the tone was present, compared to when it was absent. Using signal detection theory, we determined that this change in accuracy was reflected in an increase in d“, while we found no evidence to suggest that participants' response bias (as reflected nearly equal beta parameters), changed due to the presence of the sounds.