Fig. 1. Experimental design and prior-entry effect.

A spatial temporal order judgement (TOJ) task was used in which participants were presented with (a) a pair of spatialized stimuli which could be auditory, visual or audiovisual. Participants reported whether the first stimulus occurred on their left or on their right side, irrespective of its sensory modality. Three main experimental conditions were tested (b) to control for attentional biases in participants’ Point of Subjective Simultaneity (PSS): in visual attention blocks (red), participants attended to visual events while trials could be audiovisual (AV) or visual only (VV). In the split-attention blocks (orange), participants paid equal attention to the auditory and to the visual events and trials could be audiovisual (AV) or unisensory (AA or VV). In the auditory attention blocks (blue), participants attended to auditory events, and trials could be audiovisual (AV) or auditory only (AA). In split-attention conditions, responses were sorted as a function of which sensory modality was perceived first, yielding (c) an estimate of the probability to report seeing the flash first (% ‘flash first’) as a function of Stimulus Onset Asynchrony (SOA). Results for one representative participant are illustrated in the top panel. PSSs were estimated on a per individual basis, and averaged across participants as a function of attentional condition. Grand-average PSSs per attentional condition are reported in the bottom panel. Significant differences across attentional conditions were found, replicating the prior-entry effect (gray shaded area): specifically, attending the visual modality (red) shifted the PSS so that the sound had to be presented earlier to be perceived as simultaneous as compared to when attending the auditory modality (blue). * p < .05 ; ** p< .01 ; Bars are 2 s.e.m.