When do auditory/visual differences in duration judgements occur? J. H. Wearden Keele University, Keele, UK N. P. M. Todd and L. A. Jones Manchester University, UK Four experiments examined judgements of the duration of auditory and visual stimuli. Two used a bisection method, and two used verbal estimation. Auditory/visual differences were found when durations of auditory and visual stimuli were explicitly compared and when durations from both modalities were mixed in partition bisection. Differences in verbal estimation were also found both when people received a single modality and when they received both. In all cases, the auditory stimuli appeared longer than the visual stimuli, and the effect was greater at longer stimulus durations, consistent with a “pacemaker speed” interpretation of the effect. Results suggested that Penney, Gibbon, and Meck’s (2000) “memory mixing” account of auditory/visual differences in duration judgements, while correct in some circumstances, was incomplete, and that in some cases people were basing their judgements on some preexisting temporal standard. It has been known since the 19th century that the durations of auditory and visual stimuli are usually perceived to be different, even when the stimuli actually last the same length of time. In the words of Goldstone and Lhamon (1974) “sounds are judged longer than lights”: In other words, auditory stimuli appear to last longer than visual stimuli. Wearden, Edwards, Fakhri, and Percival (1998) attributed the auditory/visual difference to differences in the operation of an underlying internal clock. The clock was proposed to be of a pacemaker–accumulator type (Gibbon, Church, & Meck, 1984), with stimuli timed in terms of the number of “ticks” from a pacemaker that were accumulated during the stimulus, and the modality effect was interpreted in terms of a faster pacemaker rate for auditory than for visual stimuli. This interpretation essentially regards the auditory/visual difference as a “pacemaker speed” effect, similar to that obtained when trains of clicks are used to apparently increase the speed of the pacemaker of a putative internal clock (Penton-Voak, Edwards, Percival, & Wearden, 1996; see also Burle & Bonnet, 1999; Burle & Casini, 2001; Droit-Volet & Wearden, 2002; Wearden et al., 1998; and Wearden, Philpott, & Win, 1999, for replications of this effect). More recently, Penney et al. (2000) concurred with the idea that pacemaker speed was faster for auditory stimuli than for visual stimuli, but added an additional qualification. They noted that most studies that had demonstrated Correspondence should be addressed to J. H. Wearden, School of Psychology, Dorothy Hodgkin Building, Keele University, Keele, Staffordshire ST5 5BG, UK. E-mail: j.h.wearden@psy.keele.ac.uk We are grateful to Carla Hawkes, Joel White, and students from TP groups for help with data collection. # 2006 The Experimental Psychology Society 1709 http://www.psypress.com/qjep DOI:10.1080/17470210500314729 THE QUARTERLY JOURNAL OF EXPERIMENTAL PSYCHOLOGY 2006, 59 (10), 1709–1724