Time Order as Psychological Bias

Abstract

Incorrectly perceiving the chronology of events can fundamentally alter people's understanding of the causal structure of the world. For example, when astronomers used the "eye and ear" method to locate stars, they showed systematic interindividual errors. In the current study, we showed that temporal-order perception may be considered a psychological bias that attention can modulate but not fully eradicate. According to Titchener's law of prior entry, attention prioritizes the perception of an event and thus can help compensate for possible interindividual differences in the perceived timing of an event by normalizing perception in time. In a longitudinal study, we tested the stability of participants' temporal-order perception across and within sensory modalities, together with the magnitude of the participants' prior-entry effect. All measurements showed the persistence of stable interindividual variability. Crucially, the magnitude of the prior-entry effect was insufficient to compensate for interindividual variability: Conscious time order was systematically subjective, and therefore traceable on an individual basis.

Keywords: attention; interindividual variability; multisensory; open data; temporal order; time consciousness.

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.

Fig. 2. Stability of individuals’ audiovisual PSS.

Distribution of (a) individual audiovisual PSS in split-attention condition (PSS_AV, orange) in the four experimental sessions (shades of grey). The within-individual variance across all sessions is reported with box plots with the bar as the median PSS value. Participants were sorted as a function of increasing PSS i.e. from requiring the sound to be presented first (negative PSS) to requiring the visual event to be presented first (positive PSS) to perceive audiovisual simultaneity. A significant Intra-Class Correlation (ICC) of .69 signified that, over the four experimental sessions, the within-individual PSS variance was smaller than the inter-individual variance. Distribution of (b) individual audiovisual PSS free of attentional bias (PSS_free, purple) in the four experimental sessions (shades of grey). Box plots of individual PSS_free were sorted as a function of PSS_AV. As previously, the ICC of .77 signified that, over the four experimental sessions, the within-individual PSS_free variance was smaller than the inter-individual variance. The sorting of PSS_AV (orange) and PSS_free (purple) showed nearly (c) the same individual ranking to the exception of individual 7. Bottom right inset: PSS_AV and PSS_free were significantly correlated (R= .92, p <.001); shaded area is 95% CI *** p< .001; bars are 2 s.e.m.

Fig. 3. Stability of individuals’ prior-entry effect.

The magnitude of prior-entry showed (a) a clear inter-individual variability with a significant ICC of .46, indicating that the magnitude of prior-entry was stable over 4 months. These results suggest that (b) an individual’s PSS fluctuated around a fixed bias (PSS_free, purple) as a function of whether the individual’s attention was oriented towards vision (red) or audition (blue). One dot is one individual’s average PSS over the four experimental sessions per experimental condition. The significant inter-individual variability of the magnitude of prior-entry indicates that the effect of attention on time order is specific to the individual. Additionally, the magnitude of prior-entry significantly (c) correlated with the absolute value of the PSS_AV, suggesting that attention could partially (but not fully due to (b)) compensate for an individual’s intrinsic temporal delays. Each dot corresponds to an individual and a session. ** p < .01