Figure 1
Protocol for active trials. All trials started with a visual cue (200 ms duration) and contained a monaural target sound presented 910–950 ms after cue offset. Subjects were asked to press the mouse button as fast as possible when they heard the target sound (a dog bark). In trials without distractor (NoDIS trials, 50%, blue box), only the cue and the target were presented. In trials with distractors (DIS trials, 50%, green box), a binaural distracting sound (300 ms duration, symbolized by black triangles) was presented during the delay. The distracting sound could equiprobably appear in three different time periods before the target onset: 410–450 ms (DIS1), 210–250 ms (DIS2), and 10–50 ms (DIS3) (see corresponding cue-distractor delays in the figure). In 75% of the (noDIS and DIS) trials, a dog facing left or right indicated in which ear (left or right) the target sound would be played (informative cue). In the other 25% of the trials, a dog facing front did not provide any indication in which ear the target sound would be played (uninformative cue)
Table 1
Summary of the statistical analyses and results. For each dependent variable, details and results (significant effect, effect size value and interpretation) of the statistical analyses are provided. The corresponding tested cognitive processes and hypotheses are also provided. RT: reaction time, AAV: Active Audio-Visual condition, PAV: Passive Audio-Visual condition amp: amplitude; inf: informative, uninf: uninformative, DIS: distractor, NS: non-significant.
| DEPENDENT VARIABLES | TESTED COGNITIVE PROCESS | HYPOTHESES | EVENT-LOCKED PR | BASELINE | INCLUDING TRIALS | STATISTICAL ANALYSIS | FACTOR(S) OR TESTED EFFECTS | TIME WINDOW (MS) | SIGNIFICANT EFFECTS | EFFECT SIZE VALUE | EFFECT SIZE INTERPRETATION | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| behavior | ||||||||||||
| A | median RT | voluntary attention orienting | inf > uninf | All | ANOVA | cue (inf, uninf) | inf < uninf | η2G = .07 | large | |||
| B | dual pattern of distractor effect | DIS1 & DIS2 < NoDIS | distractor (NoDIS, DIS1, DIS2, DIS3) | DIS1 < NoDIS and DIS3; DIS2 < NoDIS and DIS3 | η2G = .58 | moderate to large | ||||||
| pupil responses | ||||||||||||
| C | mean amp | task engagement | AAV > PAV | cue | pre-cue | NoDIS | Wilcoxon | task (AAV, PAV) | 0–500 500–1000 1000–1500 1500–2000 2000–2500 2500–3000 | NS NS NS AAV > PAV AAV > PAV AAV > PAV | r = .76 r = .84 r = .73 | large large large |
| D | mean AAV-PAV difference amp | voluntary attention orienting | inf > uninf | cue | pre-cue | NoDIS | Wilcoxon | cue (inf, uninf) | 0–500 500–1000 1000–1500 1500–2000 2000–2500 2500–3000 | NS NS inf > uninf NS NS NS | r = .38 | moderate |
| E | mean amp in PAV | control | DIS > surrogate DIS | distractor | pre-dis | DIS, surrogate DIS | Wilcoxon | distractor presence (DIS, surrogate DIS) | 0–500 500–1000 1000–1500 1500–2000 | NS DIS > surrogate DIS DIS > surrogate DIS NS | r = .49 r = .55 | moderate large |
| mean amp in AAV | control | DIS > surrogate DIS | 0–500 500–1000 1000–1500 1500–2000 | DIS > surrogate DIS DIS > surrogate DIS DIS > surrogate DIS DIS > surrogate DIS | r = .78 r = .88 r = .88 r = .85 | large large large large | ||||||
| F | mean amp | task engagement | AAV > PAV | corrected distractor (after subtraction of the surrogate DIS) | pre-dis | DIS | Wilcoxon | task (AAV, PAV) | 0–500 500–1000 1000–1500 1500–2000 | AAV > PAV AAV > PAV AAV > PAV NS | r = .48 r = .60 r = .45 | moderate large moderate |
| G | mean AAV-PAV difference amp | voluntary attention orienting | inf = uninf or uninf > inf | corrected distractor (after subtraction of the surrogate DIS) | pre-dis | DIS | Wilcoxon | cue (inf, uninf) | 0–500 500–1000 1000–1500 1500–2000 | NS | ||
| H | mean AAV-PAV difference amp | phasic activity related to task engament | DIS1 > DIS2 > DIS3 | distractor | pre-dis | DIS | Friedman | distractor position (DIS1, DIS2, DIS3) | 0–500 500–1000 1000–1500 1500–2000 2000–2500 2500–3000 | NS NS DIS1 > DIS3 DIS1 > DIS2 and DIS3 DIS1 > DIS3 DIS1 > DIS3 | W = .28 W = .33 W = .43 W = .31 | small moderate moderate moderate |
| I | mean AAV-PAV difference amp | tonic activity related to task engagement | DIS1 < DIS2 < DIS3 | distractor | pre-cue | DIS | Friedman | distractor position (DIS1, DIS2, DIS3) | –250 | DIS1 < DIS3 | W = .26 | small |
Figure 2
Behavioral results. Mean reaction time as a function of cue type (informative in brown or uninformative in orange) and distractor condition (NoDIS, DIS1, DIS2, DIS3). Error bars represent within-subject standard errors of the mean. **p < .01, ***p < .001 (after Bonferroni correction).
Figure 3
Cue-locked pupil response (group-average, 250-ms pre-cue baseline subtraction) in trials without distractor (NoDIS trials). A: Mean pupil dilation in AAV, PAV conditions and the subtraction between the two. B: Mean pupil difference curves (AAV-PAV) for informative & uninformative cue conditions. Shadowed areas surrounding the curves represent standard errors of the mean. Examples of stimuli presented to participants are shown at their relative onset (for the target, the mean onset latency is indicated). Blue areas indicate time-windows where the task (A) or the cue (B) effect are significant. For these time windows, boxplots with individual data are depicted (mean pupil dilation amplitude in 500 ms time-windows). Within each boxplot, the horizontal line represents the group median, the box the first and third quartiles, the whiskers the largest value under 1.5*IQR. (IQR = inter-quartile range). Superimposed to each boxplot, the dots represent individual means. *p < .05, ***p < .001. AAV: Active Audio-Visual condition, PAV: Passive Audio-Visual condition, inf: informative, uninf: uninformative.
Figure 4
Distractor-locked-corrected pupil response (group-average, subtraction of the surrogate DIS-locked PR & 250-ms pre-distractor baseline subtraction). A: Mean pupil dilation in AAV, PAV conditions and the subtraction between the two. B: Mean pupil difference curves for informative & uninformative cue conditions. Shadowed areas surrounding the curves represent standard errors of the mean. The blue area (A) corresponds to the time windows where the task effect is significant. For these time windows, boxplots with individual data are depicted (mean pupil dilation amplitude in 500 ms time-windows). Within each boxplot, the horizontal line represents the group median, the box the first and third quartiles, the whiskers the largest value under 1.5*IQR. (IQR = inter-quartile range). Superimposed to each boxplot, the dots represent individual means. *p < .05, **p < .01. AAV: Active Audio-Visual condition, PAV: Passive Audio-Visual condition, inf: informative, uninf: uninformative.
Figure 5
Distractor-locked pupil response (group-average, AAV-PAV subtraction curves) as a function of the distractor position (DIS1, DIS2, DIS3). A: with a 250-ms pre-distractor baseline subtraction. B: with a 250-ms pre-cue baseline correction. Shadowed areas surrounding the curves represent standard errors of the mean. Blue areas correspond to the time window where the distractor position is significant. For these time windows, boxplots with individual data are depicted (mean pupil dilation amplitude in 500 ms time-windows). Within each boxplot, the horizontal line represents the group median, the box the first and third quartiles, the whiskers the largest value under 1.5*IQR. (IQR = inter-quartile range). Superimposed to each boxplot, the dots represent individual means. *p < .05, **p < .01, ***p < .001. AAV-PAV: Active Audio-Visual – Passive Audio-Visual condition.