Effect of visual stimuli on temporal order judgments of a sequence of pure tones

We investigated what effect visual spatial information had on auditory temporal order judgments (TOJs) and examined what effect visual stimuli had on the TOJs of sequences of pure tones in experiment 1. The auditory stimuli were sequences of four distinct pure tones. The visual stimuli consisted of two vertically aligned flashes: one flashed before the first tone and the other flashed after the last tone. Participants judged whether the temporal order of the second and third tones in auditory stimuli occurred with the higher tone being first or the lower tone being first. As a result, the proportion of responses for higher-tone-first increased when the flash of the upper LED preceded that of the lower LED, independent of the actual temporal order. Participants in experiment 2 were asked to make simultaneity judgments instead, which were also affected by visual stimuli. The auditory stimuli in experiment 3 were the same as those in experiment 1, whereas the visual stimuli consisted of two horizontally aligned flashes. Furthermore, the participants made TOJs, which were not affected by the horizontally aligned visual stimuli. We concluded that vertically aligned visual stimuli had an effect on auditory TOJs with some response bias.