Fig 1.
Experimental design and stimuli.
A: Participants completed a CTOJ task during which they determined whether a flash (gray border at the edge of the screen) or a beep occurred first. SOAs ranged from -500–500 with negative SOAs indicating that the beep occurred first. B: Some participants completed the CTOJ task while completing a secondary task with visual distractors. Participants were instructed to either ignore the distractors (NL), report a yellow letter (LL), or report a number (HL). C: The remaining participants completed the CTOJ task while completing a secondary task with auditory distractors. Participants were instructed to either ignore the distractors (NL), report a tone that was two octaves above the standard tones (LL), or report a tone that was twice the length of the standard tone (HL).
Fig 2.
Percent flash first reports across SOA for the CTOJ task separated by visual versus auditory distractor tasks.
SOA significantly influenced the percent of flash-first reports with positive SOAs (visual leading) resulting in more visual first reports. SOA and perceptual load significantly interacted for both distractor modalities indicating that perceptual load modulates performance on the CTOJ task. Error bars represent the SEM. * indicate significant differences between NL and HL and/or NL and LL at the Bonferroni-corrected alpha level of p < .0018.
Fig 3.
Features of the psychometric function.
Individual participant data was fit with a psychometric function for each perceptual load. The resulting mean PSS (A), nJND (B), and pJND (C) are shown grouped by the modality of the distractor task. Both the nJND and pJND, but not the PSS, increased with increasing load. No significant effects of distractor modality were found. Error bars represent SEM. * Indicate significant differences (p < .0125) as compared to NL.
Fig 4.
Performance on the visual and auditory distractor tasks.
Accuracy was lower for HL compared to LL for both visual and auditory distractors. Additionally, accuracy was higher for the visual distractor task then the auditory distractor task. Error bars represent SEM. * Indicate significance differences between LL and HL.