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. 2020 Jul 8;287(1930):20200825.
doi: 10.1098/rspb.2020.0825. Epub 2020 Jul 8.

Idiosyncratic perception: a link between acuity, perceived position and apparent size

Zixuan Wang  1 , Yuki Murai  1   2   3 , David Whitney  1   4   5
Affiliations

Idiosyncratic perception: a link between acuity, perceived position and apparent size

Zixuan Wang et al. Proc Biol Sci. .

Abstract

Perceiving the positions of objects is a prerequisite for most other visual and visuomotor functions, but human perception of object position varies from one individual to the next. The source of these individual differences in perceived position and their perceptual consequences are unknown. Here, we tested whether idiosyncratic biases in the underlying representation of visual space propagate across different levels of visual processing. In Experiment 1, using a position matching task, we found stable, observer-specific compressions and expansions within local regions throughout the visual field. We then measured Vernier acuity (Experiment 2) and perceived size of objects (Experiment 3) across the visual field and found that individualized spatial distortions were closely associated with variations in both visual acuity and apparent object size. Our results reveal idiosyncratic biases in perceived position and size, originating from a heterogeneous spatial resolution that carries across the visual hierarchy.

Keywords: individual difference; size perception; spatial biases; spatial localization; visual acuity.

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Conflict of interest statement

The authors declare no competing interests.

Figures

Figure 1.
Figure 1.
Experimental paradigm and results for Experiment 1. (a) Left: observers fixated at the centre and a target was displayed briefly at one of five possible eccentricities (depicted by dashed lines, which were not visible in the experiment). Right: after the target disappeared, observers moved the cursor to match the target's location. (b) All nine individual observers' spatial distortion indices plotted as distortion maps. The colour gradient represents the degree of distortion, with blue indicating contracted visual space and red for expanded. See electronic supplementary material, figure S1 for grey-scale luminance-defined distortion maps. (c) Averaged within versus between-subject correlation calculated by bootstrap procedures (see Experiment 1, Method). There was significantly higher within-observer agreement than between-observer agreement, indicating that each observer had a unique pattern of spatial distortions. The error bars represent the bootstrapped 95% CI. (Online version in colour.)
Figure 2.
Figure 2.
Paradigm and results for Experiment 2. (a) Example Vernier stimuli. Stimuli were shown on an invisible circle with a radius of 6 d.v.a. (dotted line). (b) Psychometric curves fitted for one representative subject. The colours of the lines correspond to locations in the visual field that had different types of distortion (blue for compression and red for expansion, as measured in Experiment 1); the weights of the lines correspond to the intensity of the distortion. (c) A visualization of the correlation between Vernier acuity JNDs (Experiment 2) and corresponding spatial distortion indices (Experiment 1) for all 7 observers (represented by different shapes and sizes) collapsed into a single super-subject. Blue shading indicates more contracted locations and red shading indicates more expanded locations from Experiment 1. The black line is the best-fitted linear regression line based on this super-subject data and the grey-shaded area represents the 95% CI of the linear fit. There was a significant positive correlation between the degree of visual space distortion and Vernier JNDs, indicating that better acuity was found at perceptually contracted visual space compared to expanded visual space. (Online version in colour.)
Figure 3.
Figure 3.
Experiment 3 paradigm and results. (a) Example arc stimulus used in the experiment. On each trial, an arc was presented at one of the 20 locations separated by 18° at an eccentricity of 6 d.v.a. Upon the offset of the arc, observers responded whether it was shorter or longer than the average. (b) Top: psychometric curves fitted for all three observers (Subjects 2 and 3 are authors). The abscissa represents the angular size difference between the presented and the mean arc. Colours of the lines correspond to different distortions obtained from individual subjects in Experiment 1 (blue for compression and red for expansion) and the weights of the curves correspond to the intensity of the distortion. Bottom: the association between the idiosyncratic visual space distortions (abscissa, from Experiment 1) and perceived size (ordinate) for each subject. The colour scale corresponds to the extent of compression or expansion quantified by the spatial distortion indices in Experiment 1. The positive correlations indicate that in regions of contracted (expanded) visual space, objects were perceived to be larger (smaller) than their actual size. The grey-shaded area around the regression line demonstrates the 95% CI of the linear regression fit. (Online version in colour.)
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References

    1. Suzuki S, Cavanagh P. 1997. Focused attention distorts visual space: an attentional repulsion effect. J. Exp. Psychol. Hum. Percept. Perform. 23, 443 (10.1037/0096-1523.23.2.443) - DOI - PubMed
    1. Whitney D, Cavanagh P. 2000. Motion distorts visual space: shifting the perceived position of remote stationary objects. Nat. Neurosci. 3, 954–959. (10.1038/78878) - DOI - PubMed
    1. Burr DC, Morrone MC, Ross J. 2001. Separate visual representations for perception and action revealed by saccadic eye movements. Curr. Biol. 11, 798–802. (10.1016/S0960-9822(01)00183-X) - DOI - PubMed
    1. Kosovicheva A, Whitney D. 2017. Stable individual signatures in object localization. Curr. Biol. 27, R700–R701. (10.1016/j.cub.2017.06.001) - DOI - PMC - PubMed
    1. Abrams J, Nizam A, Carrasco M. 2012. Isoeccentric locations are not equivalent: The extent of the vertical meridian asymmetry. Vision Res. 52, 70–78. (10.1016/j.visres.2011.10.016) - DOI - PMC - PubMed

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