Nonsymbolic-Magnitude Deficit in Adults With Developmental Dyscalculia: Evidence of Impaired Size Discrimination but Intact Size Constancy

2021 ◽  
pp. 095679762199520
Author(s):  
Nirit Fooks ◽  
Bat-Sheva Hadad ◽  
Orly Rubinsten
Keyword(s):  
Size Constancy ◽  
Size Discrimination ◽  
Depth Cues ◽  
Developmental Dyscalculia ◽  
Core Deficit ◽  
Depth Ordering

Although researchers have debated whether a core deficit of nonsymbolic representation of magnitude underlies developmental dyscalculia (DD), research has mostly focused on numerosity processing. We probed the possibility of a general magnitude deficit in individuals with DD and asked whether sensitivity to size varied in contexts of depth ordering and size constancy. We measured full psychometric functions in size-discrimination tasks in 12 participants with DD and 13 control participants. Results showed that although people with DD exhibited veridical perceived magnitude, their sensitivity to size was clearly impaired. In contrast, when objects were embedded in depth cues allowing size-constancy computations, participants with DD demonstrated typical sensitivity to size. These results demonstrate a deficit in the perceptual resolutions of magnitude in DD. At the same time, the finding of an intact size constancy suggests that when magnitude perception is facilitated by implicit mandatory computations of size constancy, this deficit is no longer evident.

Developmental Dyscalculia in Adults: Beyond Numerical Magnitude Impairment

2017 ◽  
Vol 51 (6) ◽  
pp. 600-611 ◽  
Author(s):  
Alice De Visscher ◽  
Marie-Pascale Noël ◽  
Mauro Pesenti ◽  
Valérie Dormal
Keyword(s):  
Mental Representation ◽  
Healthy Adults ◽  
Numerical Magnitude ◽  
Developmental Dyscalculia ◽  
Common System ◽  
The Core ◽  
Magnitude Processing ◽  
Core Deficit ◽  
Face Categorization ◽  
Numerical Magnitudes

Numerous studies have tried to identify the core deficit of developmental dyscalculia (DD), mainly by assessing a possible deficit of the mental representation of numerical magnitude. Research in healthy adults has shown that numerosity, duration, and space share a partly common system of magnitude processing and representation. However, in DD, numerosity processing has until now received much more attention than the processing of other non-numerical magnitudes. To assess whether or not the processing of non-numerical magnitudes is impaired in DD, the performance of 15 adults with DD and 15 control participants was compared in four categorization tasks using numerosities, lengths, durations, and faces (as non-magnitude-based control stimuli). Results showed that adults with DD were impaired in processing numerosity and duration, while their performance in length and face categorization did not differ from controls’ performance. Our findings support the idea of a nonsymbolic magnitude deficit in DD, affecting numerosity and duration processing but not length processing.

Neurological models of size scaling

2003 ◽  
Vol 26 (4) ◽  
pp. 425-425
Author(s):  
Helen E. Ross
Keyword(s):  
Perceptual Learning ◽  
Relative Size ◽  
Size Perception ◽  
Size Constancy ◽  
Size Discrimination ◽  
Size Scaling ◽  
Geometrical Illusions

Lehar argues that a simple Neuron Doctrine cannot explain perceptual phenomena such as size constancy but he fails to discuss existing, more complex neurological models. Size models that rely purely on scaling for distance are sparse, but several models are also concerned with other aspects of size perception such as geometrical illusions, relative size, adaptation, perceptual learning, and size discrimination.

The Site of Size Constancy

Perception ◽  
1972 ◽  
Vol 1 (1) ◽  
pp. 111-119 ◽  
Author(s):  
C Blakemore ◽  
E T Garner ◽  
J A Sweet
Keyword(s):  
Visual Cortex ◽  
Spatial Frequency ◽  
Neural Mechanism ◽  
Angular Width ◽  
Size Constancy ◽  
Depth Cues ◽  
Black And White ◽  
Maximum Elevation ◽  
Constancy Scaling ◽  
High Contrast Grating

Under appropriate conditions, with good depth cues, the perception of the bar width or spatial frequency of a pattern of black and white stripes (a grating) shows excellent size constancy. Two gratings at different distances look similar in spatial frequency when the actual width, not the angular width, of their stripes is the same. Adaptation to a high-contrast grating causes a rise in the threshold contrast for detecting gratings of similar orientation and spatial frequency. This aftereffect transfers from one eye to the other, so it probably depends on binocular orientation-selective neurones in the visual cortex. With the adapting grating at three times the distance of the test grating the maximum elevation of threshold occurs for exactly the same angular spatial frequency as that of the adapting pattern. Therefore the neural mechanism for size-constancy scaling probably occurs after the visual cortex, perhaps in the inferotemporal cortex.

scholarly journals Probabilities of perceptual depth ordering in transparent motion and the relative effect of different depth cues

2010 ◽  
Vol 7 (9) ◽  
pp. 744-744
Author(s):  
R. Moreno-Bote ◽  
A. Shipiro ◽  
J. Rinzel ◽  
N. Rubin
Keyword(s):  
Relative Effect ◽  
Depth Cues ◽  
Transparent Motion ◽  
Depth Ordering

The Ponzo Illusion in Virtual Environments: Correctly Applied Size Constancy?

1996 ◽  
Vol 40 (11) ◽  
pp. 551-554
Author(s):  
Robert A. King ◽  
Greg E. Fujawa ◽  
Kelly G. Elliott
Keyword(s):  
Effect Size ◽  
Rating Scale ◽  
Linear Trend ◽  
Relative Size ◽  
Ponzo Illusion ◽  
Linear Perspective ◽  
Size Constancy ◽  
Relative Height ◽  
Significant Linear Trend ◽  
Depth Cues

The perceived size of a stimulus can be greatly influenced by the surrounding depth cues. The effect size of the Ponzo Illusion was tested in a virtual environment with many depth cues (MC) and few depth cues (FC) conditions. The effect of size and the depth cues on the perceived proximal size of the stimulus was measured. Methods. A modified Wheatstone stereoscope was used to present the stimuli on a monitor positioned 80 cm from the subjects. The subjects used a 6AFC confidence rating scale to indicate whether the first or second of two sequentially presented stimuli had a greater proximal extent. The ‘many cues’ (MC) condition included texture, relative height, foreshortening, linear perspective, relative brightness, and relative size. The few cues condition consisted of linear perspective, relative height, and relative size. Stimulus size (proximal extent) was varied independently from all other depth cues. Results. Both depth cue context and proximal size were found to have a significant effect on the perceived proximal size for FC conditions. However, for MC conditions only the depth cues, and not proximal size, had an effect on perceived proximal size. The effect size for both depth cues and proximal size had a significant linear trend. But proximal size had a larger trend that was significantly related to the size constancy function.

Subjective Towers: Depth Relationships in Multilevel Subjective Contours

1982 ◽  
Vol 55 (3_suppl) ◽  
pp. 1247-1256 ◽  
Author(s):  
Billie Salzman ◽  
Diane F. Halpern
Keyword(s):  
Pattern Recognition ◽  
Subjective Contour ◽  
Size Constancy ◽  
Depth Cues ◽  
Depth Processing ◽  
Constancy Scaling ◽  
Significant Size ◽  
Subjective Surfaces ◽  
Depth Effects

The perceived depth associated with subjective contours was studied with a three-level subjective contour configuration. An analysis of subjects' size judgments showed significant size-constancy scaling consistent with the prediction that subjects would perceive the various subjective surfaces as superimposed upon one another in depth. Direct depth estimations, however, showed only weak depth effects, easily reversed by conflicting depth cues, and observed with real, as well as subjective contours. The discrepant results point to the possibility of different functional depth cues for the two tasks. The order of tasks, indicative of priming, further suggested that depth processing may be secondary to pattern recognition rather than being causal in the formation of subjective contours.

scholarly journals Combining depth cues: effects upon accuracy and speed of performance in a depth-ordering task

2004 ◽  
Vol 44 (6) ◽  
pp. 557-562 ◽  
Author(s):  
George Mather ◽  
David R.R Smith
Keyword(s):  
Depth Cues ◽  
Depth Ordering
Sign in / Sign up

Export Citation Format

Share Document