Visual illusions help reveal the primitives of number perception.

Picon, Edwina L; Dramkin, Denitza; Odic, Darko

doi:10.1037/xge0000553

Cited by 26 publications

(41 citation statements)

References 54 publications

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“…That is, congruity effects may reflect a perceptual interaction between numerical and non-numerical dimensions, wherein the irrelevant dimension influences perception of the relevant dimension, making it difficult to attend to, and judge only, the relevant dimension. Importantly, such effects may also reflect discriminability of the dimensions (with more discriminable dimensions exerting greater influence over less discriminable dimensions), and there may also be entirely different magnitude interactions that arise via non-perceptual mechanisms (e.g., response stage; Picon, Dramkin, & Odic, 2019) such as when judgments of Arabic numerals are affected by the physical sizes of those numerals (e.g., Henik & Tzelgov, 1982). Future work will be needed to directly examine what mechanisms (perceptual vs. non perceptual) underlie specific effects, such as congruency effects on tasks of explicit magnitude comparison, given that the present work provides evidence for perceptual mechanisms underlying some magnitude interactions, not that there are only perceptual mechanisms underlying all magnitude interactions.…”

Section: Discussionmentioning

confidence: 99%

Numerosity and cumulative surface area are perceived holistically as integral dimensions.

Aulet¹,

Lourenco²

2021

Journal of Experimental Psychology: General

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Human and non-human animals have the remarkable capacity to rapidly estimate the quantity of objects in the environment. The dominant view of this ability posits an abstract numerosity code, uncontaminated by non-numerical visual information. The present study provides novel evidence in contradiction to this view by demonstrating that number and cumulative surface area are perceived holistically, classically known as integral dimensions. Whether assessed explicitly (Experiment 1) or implicitly (Experiment 2), perceived similarity for dot arrays that varied parametrically in number and cumulative area was best modeled by Euclidean, as opposed to city-block, distance within the stimulus space, comparable to other integral dimensions (brightness/saturation and radial frequency components), but different from separable dimensions (shape/color and brightness/size). Moreover, Euclidean distance remained the bestperforming model, even when compared to models that controlled for other magnitude properties (e.g., density) or image similarity. These findings suggest that numerosity perception entails the obligatory processing of non-numerical magnitude.

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Section: Discussionmentioning

confidence: 99%

Numerosity and cumulative surface area are perceived holistically as integral dimensions.

Aulet¹,

Lourenco²

2021

Journal of Experimental Psychology: General

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“…This theory ts well with the characteristics of lateral inhibition of neurons in early visual pathways and the known properties of activation as measured with fMRI (Schwarzkopf, Song, & Rees, 2011). Rose and Bressan (2002) researched the Ebbinghaus illusion (see Fig 1B), which is closely related to the Delboeuf illusion (Girgus, Coren, & Agdern, 1972;Mruczek et al, 2017;Picon, Dramkin, & Odic, 2019;Roberts et al, 2005), by same-shape illusions (i.e., with an identically shaped test and inducer) and different-shape illusions (i.e., the test gure was a circle and the inducers were circles, hexagons, triangles, or angular shapes). The results showed that inducer shape had a signi cant effect; same-shape illusions were signi cantly larger than different-shape illusions with circles or triangles as the test stimuli.…”

Section: Introductionmentioning

confidence: 86%

Effect of Shape on the Magnitude of the Delboeuf Illusion

Li¹,

Zhang²,

Yin³

2020

Preprint

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Three experiments to discuss the applicability of the contour attraction and the parallel attraction to different shapes in the Delboeuf illusion. The contour attraction suggests that the contours of the test figure and the inducer have an effect of interattraction in the Delboeuf illusion, and the parallel attraction suggests that the attraction between non-intersecting contours was maximal when they were parallel. In Experiment 1, the shape of the test figures and the inducers changed simultaneously and formed parallel lines. In Experiment 2, the test figures remained circles while the inducers changed shape. Experiment 3 was identical to Experiment 2 except that the areas of the inducers remained equal. The results demonstrated that the illusion is influenced by shape. Importantly, the effect of shape on the magnitude of the Delboeuf illusion is based on the contour attraction and the parallel attraction. Configurations with circles or shapes more similar to a circle were related more to the contour attraction, whereas shapes that were dissimilar to a circle were related more to the parallel attraction. We suggest that the contour attraction may be a circular modality of the parallel attraction.

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“…Visual illusions could be the ideal tool to dissociate the subjective perception of (discrete) numerosity from continuous features because they help to reveal the relationship between physical stimulation (e.g., at the retinal level) and the subjective perception of the visual input. Therefore, they can be used to selectively manipulate a visual feature without compromising other physical visual features in the image (e.g., Picon et al, 2019 ). For instance, the connectedness illusion has been used to manipulate the level of perceived segmentation of the items in a set, keeping constant the low-level features across connectedness levels (Adriano, Girelli, et al, 2021 ; Adriano, Rinaldi, et al, 2021 ; Franconeri et al, 2009 ; Kirjakovski & Matsumoto, 2016 ).…”

mentioning

confidence: 99%

“…Size illusions are perceptual phenomena in which the physical size of a stimulus is altered by contextual cues. For instance, Picon et al ( 2019 ) contingently manipulated numerosity and perceived size, embedding numerical arrays in the classic Ebbinghaus illusion context. Results showed that participants significantly overestimated the number of dots presented in a perceived larger convex hull and underestimated the number of dots presented in the perceived smaller convex hull.…”

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confidence: 99%

Number is not just an illusion: Discrete numerosity is encoded independently from perceived size

2021

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While seminal theories suggest that nonsymbolic visual numerosity is mainly extracted from segmented items, more recent views advocate that numerosity cannot be processed independently of nonnumeric continuous features confounded with the numerical set (i.e., such as the density, the convex hull, etc.). To disentangle these accounts, here we employed two different visual illusions presented in isolation or in a merged condition (e.g., combining the effects of the two illusions). In particular, in a number comparison task, we concurrently manipulated both the perceived object segmentation by connecting items with Kanizsa-like illusory lines, and the perceived convex-hull/density of the set by embedding the stimuli in a Ponzo illusion context, keeping constant other low-level features. In Experiment 1, the two illusions were manipulated in a compatible direction (i.e., both triggering numerical underestimation), whereas in Experiment 2 they were manipulated in an incompatible direction (i.e., with the Ponzo illusion triggering numerical overestimation and the Kanizsa illusion numerical underestimation). Results from psychometric functions showed that, in the merged condition, the biases of each illusion summated (i.e., largest underestimation as compared with the conditions in which illusions were presented in isolation) in Experiment 1, while they averaged and competed against each other in Experiment 2. These findings suggest that discrete nonsymbolic numerosity can be extracted independently from continuous magnitudes. They also point to the need of more comprehensive theoretical views accounting for the operations by which both discrete elements and continuous variables are computed and integrated by the visual system.

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Visual illusions help reveal the primitives of number perception.

Abstract: Grouping effects in numerosity perception under prolonged viewing conditions. PLoS ONE, 14(2), e0207502.

Cited by 26 publications

References 54 publications

Numerosity and cumulative surface area are perceived holistically as integral dimensions.

Numerosity and cumulative surface area are perceived holistically as integral dimensions.

Effect of Shape on the Magnitude of the Delboeuf Illusion

Number is not just an illusion: Discrete numerosity is encoded independently from perceived size

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