Body ownership promotes visual awareness
- Karolinska Institutet, Sweden
Figures
Figure 1
Experimental setup and visual stimuli.
A participant indicates the current dominant percept with her left hand while the experimenter applies synchronous tactile stimulation to the right hand (A). The visual stimuli used in Experiment 1: the visuotactile condition and visual-only condition (B); the tactile-only condition, no-stimulation condition, and baseline condition (C); and the visual stimuli used in Experiment 2: the congruent visuotactile condition and congruent visual-only condition (D) and the incongruent visuotactile condition and incongruent visual-only condition (E).
Figure 2
Ownership illusion.
Median ratings of the different items of the questionnaire in Experiment 1 (A) and Experiment 2 (B). Q1: ‘It felt as if the hand I saw was my own hand’; Q2: ‘The touch I felt seemed to be caused by the white ball I saw’; Q3: ‘My own hand started to feel digital’; Q4: ‘I felt as if I had two right hands at the same time.’ Q1 and Q2 capture the ownership illusion, and Q3 and Q4 control for expectancy effects and response bias. Blue indicates the congruent visuotactile condition; red indicates the incongruent visuotactile condition. Error bars indicate the interquartile range.
Figure 3
Hand-percept dominance.
Average dominance of the hand percept in the different conditions of Experiment 1 (A) and Experiment 2 (B). Error bars indicate SE. *p <0.05, ***p <0.001.
Figure 4
Ownership and dominance.
Correlation between illusion scores (Q1 +Q2 - Q3 - Q4) and the normalized overall dominance in the visuotactile condition for Experiment 1 (A) and Experiment 2 (B). **p <0.01.
Figure 5
Switch rate.
The mean switch rate in the different conditions of Experiment 1 (A) and Experiment 2 (B). Error bars indicate SEM. ***p < 0.001.
Figure 6
Percept durations.
The mean normalized durations of the hand percept and the mask percept for Experiment 1 (A) and Experiment 2 (B) and the duration difference between the visuotactile condition and the visual-only condition across experiments (C). † p = 0.057, ‡ p = 0.063, *p < 0.05, ***p < 0.001.
Figure 7
Effect of individual touches on hand-percept dominance (Experiment 1).
Dominance of the hand percept as a function of time around individual touches (t = 0–667 ms) for the different conditions of Experiment 1 (A). The difference between the visuotactile condition and the visual-only condition (B), the difference between the tactile-only condition and the no-stimulation condition (C), and the difference between B and C (D). The gray zone indicates the period of touch (0–667 ms). For panels B-D: pp indicates percentage points (y-axis) and shading indicates SEM.
Figure 8
Maintaining and switching percepts.
The probability of maintaining when the hand percept is dominant (A, C) and the probability of switching when mask percept is dominant (B, D), before a touch and during a touch, for Experiment 1 (A, B) and Experiment 2 (C, D). Error bars indicate SEM. *p < 0.05, **p < 0.01.
Figure 9
Effect of individual touches on hand-percept dominance (Experiment 2).
Dominance of the hand percept as a function of time around individual touches (t = 0–667 ms) for the different conditions of Experiment 2 (A). The difference between the congruent conditions (B), the difference between the incongruent conditions (C), and the difference between B and C (D). The gray zone indicates the period of touch (0–667 ms). For panels B-D: pp indicates percentage points (y-axis) and shading indicates SEM.
Tables
Table 1
Paired t-test statistics.
Comparison of hand-image dominance between T0 and T1-4 (see Figure 7 and Figure 9); p-values are Bonferroni corrected for multiple comparisons. Significant differences are displayed in bold.
| T1 (0–333 ms) | T2 (333–667 ms) | T3 (667–1000 ms) | T4 (1000–1334 ms) | ||
|---|---|---|---|---|---|
| Experiment 1 | Visuotactile | t(29) = 0.21 p > 0.50 | t(29) = 3.49 p = 0.008 | t(29) = 7.12 p < 0.001 | t(29) = 7.72 p < 0.001 |
| Visual-only | t(29) = 1.83 p = 0.31 | t(29) = 4.68 p < 0.001 | t(29) = 10.05 p < 0.001 | t(29) = 9.58 p < 0.001 | |
| Experiment 2 | Congruent Visuotactile | t(29) = 1.86 p = 0.29 | t(29) = 3.85 p = 0.002 | t(29) = 6.18 p < 0.001 | t(29)=7.81 p < 0.001 |
| Congruent Visual-only | t(29) = 1.02 p > 0.50 | t(29) = 3.84 p = 0.002 | t(29) = 6.75 p < 0.001 | t(29) = 8.85 p < 0.001 | |
| Incongruent Visuotactile | t(29) = 1.15 p > 0.50 | t(29) = 2.91 p = 0.027 | t(29) = 5.15 p < 0.001 | t(29) = 7.53 p < 0.001 | |
| Incongruent Visual-only | t(29) = 0.31 p > 0.50 | t(29) = 1.53 p > 0.50 | t(29) = 5.11 p < 0.001 | t(29) = 8.55 p < 0.001 |
Additional files
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Transparent reporting form
- https://doi.org/10.7554/eLife.26022.012
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Body ownership promotes visual awareness
eLife 6:e26022.
https://doi.org/10.7554/eLife.26022
