Investigating the crowding effect on letters and symbols in deaf adults.

Reading requires the transformation of a complex array of visual features into sounds and meaning. For deaf signers who experience changes in visual attention and have little or no access to the sounds of the language they read, understanding the visual constraints underlying reading is crucial. This study aims to explore a fundamental aspect of visual perception intertwined with reading: the crowding effect.

Enhancing mathematics learning through finger-counting: A study investigating tactile strategies in 2 visually impaired cases.

Finger-counting plays a crucial role in grounding and establishing mathematics, one of the most abstract domains of human cognition. While the combination of visual and proprioceptive information enables the coordination of finger movements, it was recently suggested that the emergence of finger-counting primarily relies on visual cues. In this study, we aimed to directly test this assumption by examining whether explicit finger-counting training (through tactile stimulation) may assist visually impaired children in overcoming their difficulties in learning mathematics.

Frequency-tagging EEG reveals the effect of attentional focus on abstract magnitude processing.

While humans can readily access the common magnitude of various codes such as digits, number words, or dot sets, it remains unclear whether this process occurs automatically, or only when explicitly attending to magnitude information. We addressed this question by examining the neural distance effect, a robust marker of magnitude processing, with a frequency-tagging approach. Electrophysiological responses were recorded while participants viewed rapid sequences of a base numerosity presented at 6 Hz (e.

Stronger neural response to canonical finger-number configurations in deaf compared to hearing adults revealed by FPVS-EEG.

The linguistic counting system of deaf signers consists of a manual counting format that uses specific structures for number words. Interestingly, the number signs from 1 to 4 in the Belgian sign languages correspond to the finger-montring habits of hearing individuals. These hand configurations could therefore be considered as signs (i.

Deafness and early language deprivation influence arithmetic performances.

It has been consistently reported that deaf individuals experience mathematical difficulties compared to their hearing peers. However, the idea that deafness and early language deprivation might differently affect verbal (i.e.

A shared numerical magnitude representation evidenced by the distance effect in frequency-tagging EEG.

Humans can effortlessly abstract numerical information from various codes and contexts. However, whether the access to the underlying magnitude information relies on common or distinct brain representations remains highly debated. Here, we recorded electrophysiological responses to periodic variation of numerosity (every five items) occurring in rapid streams of numbers presented at 6 Hz in randomly varying codes-Arabic digits, number words, canonical dot patterns and finger configurations.

Impact of deafness on numerical tasks implying visuospatial and verbal processes.

The literature suggests that deaf individuals lag behind their hearing peers in terms of mathematical abilities. However, it is still unknown how unique sensorimotor experiences, like deafness, might shape number-space interactions. We still do not know either the spatial frame of reference deaf individuals use to map numbers onto space in different numerical tasks.

Geometry intuitions without vision? A study in blind children and adults.

Geometry intuitions seem to be rooted in a non-verbal system that humans possess since early age. However, the mechanisms underlying the comprehension of basic geometric concepts remain elusive. Some authors have suggested that the starting point of geometry development could be found in the visual perception of specific features in our environment, thus conferring to vision a foundational role in the acquisition of geometric skills.

Canonical representations of fingers and dots trigger an automatic activation of number semantics: an EEG study on 10-year-old children.

Over the course of development, children must learn to map a non-symbolic representation of magnitude to a more precise symbolic system. There is solid evidence that finger and dot representations can facilitate or even predict the acquisition of this mapping skill. While several behavioral studies demonstrated that canonical representations of fingers and dots automatically activate number semantics, no study so far has investigated their cerebral basis.

Early visual deprivation does not prevent the emergence of basic numerical abilities in blind children.

Studies involving congenitally blind adults shows that visual experience is not a mandatory prerequisite for the emergence of efficient numerical abilities. It remains however unknown whether blind adults developed lifelong strategies to compensate for the absence of foundations vision would provide in infancy. We therefore assessed basic numerical abilities in blind and sighted children of 6 to 13 years old.

Tactile numerosity is coded in external space.

Humans, and several non-human species, possess the ability to make approximate but reliable estimates of the number of objects around them. Alike other perceptual features, numerosity perception is susceptible to adaptation: exposure to a high number of items causes underestimation of the numerosity of a subsequent set of items, and vice versa. Several studies have investigated adaptation in the auditory and visual modality, whereby stimuli are preferentially encoded in an external coordinate system.

How visual is the « number sense »? Insights from the blind.

Is vision a necessary building block for the foundations of mathematical cognition? A straightforward model to test the causal role visual experience plays in the development of numerical abilities is to study people born without sight. In this review we will demonstrate that congenitally blind people can develop numerical abilities that equal or even surpass those of sighted individuals, despite representing numbers using a qualitatively different representational format. We will also show that numerical thinking in blind people maps onto regions typically involved in visuo-spatial processing in the sighted, highlighting how intrinsic computational biases may constrain the reorganization of numerical networks in case of early visual deprivation.

The shared numerical representation for action and perception develops independently from vision.

Humans share with other animals a number sense, a system allowing a rapid and approximate estimate of the number of items in a scene. Recently, it has been shown that numerosity is shared between action and perception as the number of repetitions of self-produced actions affects the perceived numerosity of subsequent visual stimuli presented around the area where actions occurred. Here we investigate whether this interplay between action and perception for numerosity depends on visual input and visual experience.

Investigating the respective contribution of sensory modalities and spatial disposition in numerical training.

Recent studies have suggested that multisensory redundancy may improve cognitive learning. According to this view, information simultaneously available across two or more modalities is highly salient and, therefore, may be learned and remembered better than the same information presented to only one modality. In the current study, we wanted to evaluate whether training arithmetic with a multisensory intervention could induce larger learning improvements than a visual intervention alone.

How visual experience and task context modulate the use of internal and external spatial coordinate for perception and action.

Recent studies proposed that the use of internal and external coordinate systems for perception and action may be more flexible in congenitally blind when compared to sighted individuals. To investigate this hypothesis further, we asked congenitally blind and sighted people to perform, with the hands uncrossed and crossed over the body midline, a tactile temporal order judgment and an auditory Simon task. Crucially, both tasks were carried out under task instructions either favoring the use of an internal (left vs.

Recruitment of the occipital cortex by arithmetic processing follows computational bias in the congenitally blind.

Arithmetic reasoning activates the occipital cortex of congenitally blind people (CB). This activation of visual areas may highlight the functional flexibility of occipital regions deprived of their dominant inputs or relate to the intrinsic computational role of specific occipital regions. We contrasted these competing hypotheses by characterizing the brain activity of CB and sighted participants while performing subtraction, multiplication and a control letter task.

Is Red Heavier Than Yellow Even for Blind?

Across cultures and languages, people find similarities between the products of different senses in mysterious ways. By studying what is called cross-modal correspondences, cognitive psychologists discovered that lemons are fast rather than slow, boulders are sour, and red is heavier than yellow. Are these cross-modal correspondences established via sensory perception or can they be learned merely through language? We contribute to this debate by demonstrating that early blind people who lack the perceptual experience of color also think that red is heavier than yellow but to a lesser extent than sighted do.

Author Correction: How visual experience impacts the internal and external spatial mapping of sensorimotor functions.

A correction has been published and is appended to both the HTML and PDF versions of this paper. The error has been fixed in the paper.

Visual Experience Shapes the Neural Networks Remapping Touch into External Space.

Localizing touch relies on the activation of skin-based and externally defined spatial frames of reference. Psychophysical studies have demonstrated that early visual deprivation prevents the automatic remapping of touch into external space. We used fMRI to characterize how visual experience impacts the brain circuits dedicated to the spatial processing of touch.

How visual experience impacts the internal and external spatial mapping of sensorimotor functions.

Tactile perception and motor production share the use of internally- and externally-defined coordinates. In order to examine how visual experience affects the internal/external coding of space for touch and movement, early blind (EB) and sighted controls (SC) took part in two experiments. In experiment 1, participants were required to perform a Temporal Order Judgment task (TOJ), either with their hands in parallel or crossed over the body midline.

[Numerical cognition: what can we learn from blind people?].

The representation of numbers is assumed to interact with two visuo-motor functions. On the one hand, following the observation that children often use their fingers to learn the counting sequence and basic arithmetic operations, numbers were assumed to interact with finger movements. On the other hand, following the recurrent observation that small numbers are preferentially associated with the left side of space while large numbers are preferentially associated with the right side of space, numbers were assumed to interact with space.

Early but not late blindness leads to enhanced arithmetic and working memory abilities.

Behavioural and neurophysiological evidence suggest that vision plays an important role in the emergence and development of arithmetic abilities. However, how visual deprivation impacts on the development of arithmetic processing remains poorly understood. We compared the performances of early (EB), late blind (LB) and sighted control (SC) individuals during various arithmetic tasks involving addition, subtraction and multiplication of various complexities.

Spatial and numerical processing in children with non-verbal learning disabilities.

Consistently with the idea that numbers and space interact with each other, the present paper aimed to investigate the impact of non-verbal learning disabilities (NVLD) on spatial and numerical processing. In order to do so, 15 NVLD and 15 control children were required to perform different spatial (the line bisection and Simon tasks) and numerical tasks (the number bisection, number-to-position and numerical comparison tasks). In every task, NVLD children presented lower accuracy scores than the control group.

The role of fingers in the development of counting and arithmetic skills.

Interactions between fingers and numbers have been reported in the existing literature on numerical cognition. The aim of the present research was to test whether hand interference movements might have an impact on children performance in counting and basic arithmetic problem solving. In Experiment 1, 5-year-old children had to perform both a one-target and a two-target counting task in three different conditions: with no constraints, while making interfering hand movements or while making interfering foot movements.

Spatial and numerical processing in children with high and low visuospatial abilities.

In the literature on numerical cognition, a strong association between numbers and space has been repeatedly demonstrated. However, only a few recent studies have been devoted to examine the consequences of low visuospatial abilities on calculation processing. In this study, we wanted to investigate whether visuospatial weakness may affect pure spatial processing as well as basic numerical reasoning.