scholarly journals Evidence for an A-Modal Number Sense: Numerosity Adaptation Generalizes Across Visual, Auditory, and Tactile Stimuli

2021 ◽  
Vol 15 ◽  
Author(s):  
Irene Togoli ◽  
Roberto Arrighi

Humans and other species share a perceptual mechanism dedicated to the representation of approximate quantities that allows to rapidly and reliably estimate the numerosity of a set of objects: an Approximate Number System (ANS). Numerosity perception shows a characteristic shared by all primary visual features: it is susceptible to adaptation. As a consequence of prolonged exposure to a large/small quantity (“adaptor”), the apparent numerosity of a subsequent (“test”) stimulus is distorted yielding a robust under- or over-estimation, respectively. Even if numerosity adaptation has been reported across several sensory modalities (vision, audition, and touch), suggesting the idea of a central and a-modal numerosity processing system, evidence for cross-modal effects are limited to vision and audition, two modalities that are known to preferentially encode sensory stimuli in an external coordinate system. Here we test whether numerosity adaptation for visual and auditory stimuli also distorts the perceived numerosity of tactile stimuli (and vice-versa) despite touch being a modality primarily coded in an internal (body-centered) reference frame. We measured numerosity discrimination of stimuli presented sequentially after adaptation to series of either few (around 2 Hz; low adaptation) or numerous (around 8 Hz; high adaptation) impulses for all possible combinations of visual, auditory, or tactile adapting and test stimuli. In all cases, adapting to few impulses yielded a significant overestimation of the test numerosity with the opposite occurring as a consequence of adaptation to numerous stimuli. The overall magnitude of adaptation was robust (around 30%) and rather similar for all sensory modality combinations. Overall, these findings support the idea of a truly generalized and a-modal mechanism for numerosity representation aimed to process numerical information independently from the sensory modality of the incoming signals.

2016 ◽  
Vol 116 (3) ◽  
pp. 1218-1231 ◽  
Author(s):  
Manuel Gomez-Ramirez ◽  
Kristjana Hysaj ◽  
Ernst Niebur

Selective attention allows organisms to extract behaviorally relevant information while ignoring distracting stimuli that compete for the limited resources of their central nervous systems. Attention is highly flexible, and it can be harnessed to select information based on sensory modality, within-modality feature(s), spatial location, object identity, and/or temporal properties. In this review, we discuss the body of work devoted to understanding mechanisms of selective attention in the somatosensory system. In particular, we describe the effects of attention on tactile behavior and corresponding neural activity in somatosensory cortex. Our focus is on neural mechanisms that select tactile stimuli based on their location on the body (somatotopic-based attention) or their sensory feature (feature-based attention). We highlight parallels between selection mechanisms in touch and other sensory systems and discuss several putative neural coding schemes employed by cortical populations to signal the behavioral relevance of sensory inputs. Specifically, we contrast the advantages and disadvantages of using a gain vs. spike-spike correlation code for representing attended sensory stimuli. We favor a neural network model of tactile attention that is composed of frontal, parietal, and subcortical areas that controls somatosensory cells encoding the relevant stimulus features to enable preferential processing throughout the somatosensory hierarchy. Our review is based on data from noninvasive electrophysiological and imaging data in humans as well as single-unit recordings in nonhuman primates.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jacques Pesnot Lerousseau ◽  
Gabriel Arnold ◽  
Malika Auvray

AbstractSensory substitution devices aim at restoring visual functions by converting visual information into auditory or tactile stimuli. Although these devices show promise in the range of behavioral abilities they allow, the processes underlying their use remain underspecified. In particular, while an initial debate focused on the visual versus auditory or tactile nature of sensory substitution, since over a decade, the idea that it reflects a mixture of both has emerged. In order to investigate behaviorally the extent to which visual and auditory processes are involved, participants completed a Stroop-like crossmodal interference paradigm before and after being trained with a conversion device which translates visual images into sounds. In addition, participants' auditory abilities and their phenomenologies were measured. Our study revealed that, after training, when asked to identify sounds, processes shared with vision were involved, as participants’ performance in sound identification was influenced by the simultaneously presented visual distractors. In addition, participants’ performance during training and their associated phenomenology depended on their auditory abilities, revealing that processing finds its roots in the input sensory modality. Our results pave the way for improving the design and learning of these devices by taking into account inter-individual differences in auditory and visual perceptual strategies.


2012 ◽  
Vol 25 (0) ◽  
pp. 100 ◽  
Author(s):  
Mario Pannunzi ◽  
Alexis Pérez-Bellido ◽  
Alexandre Pereda Baños ◽  
Joan López-Moliner ◽  
Gustavo Deco ◽  
...  

The level of processing at which different modalities interact to either facilitate or interfere with detection has been a matter of debate for more than half a century. This question has been mainly addressed by means of statistical models (Green, 1958), or by biologically plausible models (Schnupp et al., 2005). One of the most widely accepted statistical frameworks is the signal detection theory (SDT; Green and Swets, 1966) because it provides a straightforward way to assess whether two sensory stimuli are judged independently of one another, that is when the detectability (d′) of the compound stimulus exceeds the Pythagorean sum of the d′ of the components. Here, we question this logic, and propose a different baseline to evaluate integrative effects in multi-stimuli detection tasks based on the probabilistic summation. To this aim, we show how a simple theoretical hypothesis based on probabilistic summation can explain putative multisensory enhancement in an audio-tactile detection task. In addition, we illustrate how to measure integrative effects from multiple stimuli in two experiments, one using a multisensory audio-tactile detection task (Experiment 1) and another with a unimodal double-stimulus auditory detection task (Experiment 2). Results from Experiment 1 replicate extant multisensory detection data, and also refuse the hypothesis that auditory and tactile stimuli integrated into a single percept, leading to any enhancement. In Experiment 2, we further support the probabilistic summation model using a unimodal integration detection task.


2007 ◽  
Vol 19 (2) ◽  
pp. 315-330 ◽  
Author(s):  
Kurt E. Weaver ◽  
Alexander A. Stevens

Visual deprivation early in life results in occipital cortical responsiveness across a broad range of perceptual and cognitive tasks. In the reorganized occipital cortex of early blind (EB) individuals, the relative lack of specificity for particular sensory stimuli and tasks suggests that attention effects may play a prominent role in these areas. We wished to establish whether occipital cortical areas in the EB were responsive to stimuli across sensory modalities (auditory, tactile) and whether these areas maintained or altered their activity as a function of selective attention. Using a three-stimulus oddball paradigm and event-related functional magnetic resonance imaging, auditory and tactile tasks presented separately demonstrated that several occipital regions of interest (ROIs) in the EB, but not sighted controls (SCs), responded to targets and task-irrelevant distracter stimuli of both modalities. When auditory and tactile stimuli were presented simultaneously with subjects alternating attention between sensory streams, only the calcarine sulcus continued to respond to stimuli in both modalities. In all other ROIs, responses to auditory targets were as large or larger than those observed in the auditory-alone condition, but responses to tactile targets were attenuated or abolished by the presence of unattended auditory stimuli. Both auditory and somatosensory cortices responded consistently to auditory and tactile targets, respectively. These results reveal mechanisms of orienting and selective attention within the visual cortex of EB individuals and suggest that mechanisms of enhancement and suppression interact asymmetrically on auditory and tactile streams during bimodal sensory presentation.


2002 ◽  
Vol 19 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Eynat Gal ◽  
Murray Dyck ◽  
Anne Passmore

AbstractThis study was designed to test whether there is a functional relationship between sensory stimulation and stereotyped movements (SM). Four children with autism and intellectual disability (according to DSM-IV criteria) who showed stereotyped movements were studied. The Short Sensory Profile was used to define whether a child perceived stimulation within each sensory modality as aversive, attractive, or neutral. The Stereotyped and Self-Injurious Movements Interview was used to identify each child's repetitive movements. Children were then exposed to sensory stimuli that were neutral, aversive or attractive. Results indicate that children: (a) initiate or increase stereotyped movements immediately following the onset of an aversive stimulus, (b) terminate or decrease stereotyped movements following the onset of an attractive stimulus and (c) initiate or increase stereotyped movements during periods of neutral stimulation. We conclude that stereotyped movements are functionally related to sensory stimulation; individuals who frequently engage in stereotyped movements may do so in order to cope with under-stimulation and aversive over-stimulation.


2021 ◽  
Vol 15 ◽  
Author(s):  
Midori Tokita ◽  
Sumire Hirota

This study explores whether and how different tasks associated with approximate number system (ANS) ability are related to numeracy and cognitive reflection in adults. We conducted an online experiment using a sample of 300 Japanese adults aged 20–39. Participants were given three ANS tasks (numerosity comparison, numerosity estimation, and proportion estimation) as well as Rasch-based numeracy scale and cognitive reflection test, and we tested the correlation among the measures of these tasks. We explored the hypothesis that the typical measures used to gauge ANS ability, numerosity comparison and numerosity estimation may mediate different cognitive mechanisms in adults. We also introduced a task measuring proportion estimation, added because such estimation requires numerosity perception and the ability to map symbolic numerals. Our findings suggest that there is a weak, but significant correlation among the three ANS-related tasks. Moreover, there is a significant relationship between each of these measures and the numeracy and CRT score, suggesting that the ANS-related ability may be associated with higher cognitive abilities such as numeracy and cognitive reflection. In addition, we found that performances on the numerosity and proportion estimation are more clearly related to CRT score than the numerosity comparison task.


2019 ◽  
Author(s):  
Klaudia Grechuta ◽  
Javier De La Torre ◽  
Belén Rubio Ballester ◽  
Paul F.M.J. Verschure

AbstractThe unique ability to identify one’s own body and experience it as one’s own is fundamental in goal-oriented behavior and survival. However, the mechanisms underlying the so-called body ownership are yet not fully understood. The plasticity of body ownership has been studied using two experimental methods or their variations. Specifically, the Rubber Hand Illusion (RHI), where the tactile stimuli are externally generated, or the moving RHI which implies self-initiated movements. Grounded in these paradigms, evidence has demonstrated that body ownership is a product of bottom-up reception of self- and externally-generated multisensory information and top-down comparison between the predicted and the actual sensory stimuli. Crucially, provided the design of the current paradigms, where one of the manipulated cues always involves the processing of a proximal modality sensing the body or its surface (e.g., touch), the contribution of sensory signals which pertain to the environment remain elusive. Here we propose that, as any robust percept, body ownership depends on the integration and prediction of all the sensory stimuli, and therefore it will depend on the consistency of purely distal sensory signals pertaining to the environment. To test our hypothesis, we create an embodied goal-oriented task and manipulate the predictability of the surrounding environment by changing the congruency of purely distal multisensory cues while preserving bodily and action-driven signals entirely predictable. Our results empirically reveal that the way we represent our body is contingent upon all the sensory stimuli including purely distal and action-independent signals which pertain to the environment.


2021 ◽  
Vol 15 ◽  
Author(s):  
Elisa Castaldi ◽  
Manuela Piazza ◽  
Evelyn Eger

Humans can quickly approximate how many objects are in a visual image, but no clear consensus has been achieved on the cognitive resources underlying this ability. Previous work has lent support to the notion that mechanisms which explicitly represent the locations of multiple objects in the visual scene within a mental map are critical for both visuo-spatial working memory and enumeration (at least for relatively small numbers of items). Regarding the cognitive underpinnings of large numerosity perception, an issue currently subject to much controversy is why numerosity estimates are often non-veridical (i.e., susceptible to biases from non-numerical quantities). Such biases have been found to be particularly pronounced in individuals with developmental dyscalculia (DD), a learning disability affecting the acquisition of arithmetic skills. Motivated by findings showing that DD individuals are also often impaired in visuo-spatial working memory, we hypothesized that resources supporting this type of working memory, which allow for the simultaneous identification of multiple objects, might also be critical for precise and unbiased perception of larger numerosities. We therefore tested whether loading working memory of healthy adult participants during discrimination of large numerosities would lead to increased interference from non-numerical quantities. Participants performed a numerosity discrimination task on multi-item arrays in which numerical and non-numerical stimulus dimensions varied congruently or incongruently relative to each other, either in isolation or in the context of a concurrent visuo-spatial or verbal working memory task. During performance of the visuo-spatial, but not verbal, working memory task, precision in numerosity discrimination decreased, participants’ choices became strongly biased by item size, and the strength of this bias correlated with measures of arithmetical skills. Moreover, the interference between numerosity and working memory tasks was bidirectional, with number discrimination impacting visuo-spatial (but not verbal) performance. Overall, these results suggest that representing visual numerosity in a way that is unbiased by non-numerical quantities relies on processes which explicitly segregate/identify the locations of multiple objects that are shared with visuo-spatial (but not verbal) working memory. This shared resource may potentially be impaired in DD, explaining the observed co-occurrence of working memory and numerosity discrimination deficits in this clinical population.


2019 ◽  
Vol 56 (1) ◽  
pp. 123-141 ◽  
Author(s):  
Dipayan Biswas ◽  
Courtney Szocs

Managers are using ambient scent as an important strategic element in various service settings, with food-related scents being especially common. This research examines the effects of food-related ambient scents on children’s and adults’ food purchases/choices. The results of a series of experiments, including field studies at a supermarket and at a middle school cafeteria, show that extended exposure (of more than two minutes) to an indulgent food–related ambient scent (e.g., cookie scent) leads to lower purchases of unhealthy foods compared with no ambient scent or a nonindulgent food–related ambient scent (e.g., strawberry scent). The effects seem to be driven by cross-modal sensory compensation, whereby prolonged exposure to an indulgent/rewarding food scent induces pleasure in the reward circuitry, which in turn diminishes the desire for actual consumption of indulgent foods. Notably, the effects reverse with brief (<30 seconds) exposure to the scent. Whereas prior research has examined cross-modal effects, this research adopts the novel approach of examining cross-modal sensory compensation effects, whereby stimuli in one sensory modality (olfactory) can compensate/satisfy the desire related to another sensory modality (gustatory).


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