About individual differences in vision

In cognition, audition, and somatosensation, performance strongly correlates between different paradigms, which suggests the existence of common factors. In contrast, visual performance in seemingly very similar tasks, such as visual and bisection acuity, are hardly related, i.e., pairwise correlations between performance levels are low even though test-retest reliability is high. Here we show similar results for visual illusions. Consistent with previous findings, we found significant correlations between the illusion magnitude of the Ebbinghaus and Ponzo illusions, but this relationship was the only significant correlation out of 15 further comparisons. Similarly, we found a significant link for the Ponzo illusion with both mental imagery and cognitive disorganization. However, most other correlations between illusions and personality were not significant. The findings suggest that vision is highly specific, i.e., there is no common factor. While this proposal does not exclude strong and stable associations between certain illusions and between certain illusions and personality traits, these associations seem to be the exception rather than the rule. (C) 2016 Elsevier Ltd. All rights reserved.

Tell me about your Ponzo and I will tell you who you are

Aaron Michael Clarke, Lukasz Grzeczkowski, Michael Herzog, Fred Mast

Unlike in cognition, audition and somatosensation, performance between various visual tasks does not correlate. Surprisingly, even tasks that appear similar, like visual acuity and line bisection task do not share much common variance. Similar results were found for visual illusions. For example, the Ebbinghaus and the Müller-Lyer illusions correlate very weakly. The high intra- and inter-observer variability in visual perception is possibly due to perceptual learning, i.e., individual experience shaping perception throughout one’s life time. Here, we studied the relationship between illusion strength and high-level factors such as personality traits (O-Life) and the vividness of mental imagery (VVIQ). In line with previous findings, we found only few correlations between the magnitudes of the visual illusions, despite having high test-retest reliability. More interestingly, we found a high, positive correlation between the magnitude of the Ponzo illusion and vividness of mental imagery. Moreover, the magnitude of the Ponzo illusion was negatively correlated with cognitive disorganization personality trait. These results were specific to the Ponzo-type illusions. Principal component analysis revealed one factor, with high weights mainly on the Ponzo-type illusions, cognitive disorganization and the vividness of mental imagery.

2016

Individual differences in visual (mis)perception: a multivariate statistical approach

Aline Françoise Cretenoud

Common factors are omnipresent in everyday life, e.g., people who do well in one cognitive test are likely to perform well in other cognitive tests as well, and vice versa. In vision, however, there seems to be a multitude of specific factors rather than a strong and unique common factor. For example, only weak correlations were observed between the susceptibility to different visual illusions, suggesting that the structure underlying visual illusions is multifactorial. In this thesis, I first examined the multidimensionality of the structure underlying visual illusions. To this aim, the susceptibility to various visual illusions was measured. In addition, subjects were tested with variants of the same illusion, which differed in spatial features, luminance, orientation, or contextual conditions. In line with previous work, only weak correlations were observed between the susceptibility to different visual illusions (i.e., between-illusion). An individual showing a strong susceptibility to one visual illusion does not necessarily show a strong susceptibility to other visual illusions. In contrast, there were strong correlations between the susceptibility to variants of the same illusion (i.e., within-illusion). Hence, factors seem to be illusion-specific but not feature-specific. In addition, the susceptibility to combinations of two illusions, which I call merged illusions, was measured to investigate how factors for illusions interact. The susceptibility to a merged illusion was strongly predicted from the susceptibility to the two illusions of which it was made, suggesting that factors for illusions combine independently to form complex illusory percepts. Second, I showed that individual differences in the perception of visual illusions are robust across the eye(s) to which the stimulus is presented, over a month, and when measured with an adjustment procedure or a method of constant stimuli. Last, I investigated whether a strong visual factor emerges in healthy elderly and patients with schizophrenia, which may be expected from the general decline in perceptual abilities usually reported in these two populations compared to healthy young adults. Similarly, a strong visual factor may emerge in action video gamers, who, contrary to healthy elderly and patients with schizophrenia, often show enhanced perceptual performance compared to non-video gamers. Hence, healthy elderly, patients with schizophrenia, and action video gamers were tested with a battery of visual tasks, such as a contrast detection and orientation discrimination task. As in control groups, between-task correlations were weak in general, which argues against the emergence of a strong common factor for vision in these populations. While similar tasks are usually assumed to rely on similar neural mechanisms, the performances in different visual tasks were only weakly related to each other, i.e., performance does not generalize across visual tasks. The results presented in this thesis highlight the relevance of an individual differences approach to unravel the multidimensionality of the visual structure.

EPFL2021

Individual differences in visual (mis)perception: a multivariate statistical approach

Aline Françoise Cretenoud

EPFL2021