Higher attentional costs for numerosity estimation at high densities

Pomè, Antonella; Anobile, Giovanni; Cicchini, Guido Marco; Scabia, Aurora; Burr, David

doi:10.3758/s13414-019-01831-3

Cited by 38 publications

(32 citation statements)

References 35 publications

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“…Although subitizing was originally thought to be pre-attentive, dependence on attention has become a signature of the subitizing system. Many studies have shown that attention has a much stronger detrimental effect in the subitizing than estimation range, enough to equate subitizing precision and reaction times to those of higher numerosities during dual tasks 10 , 12 , 19 – 21 . The selective detrimental effect of attentional deprivation in the subitizing range was reinforced by a recent clinical single case study with a simultanagnosic patient (PA) 22 , who suffered a severe visual attentional deficit.…”

Section: Discussionmentioning

confidence: 99%

“…However, there is some evidence for interconnection between the systems. Under dual task conditions, sensory thresholds for estimating numerosities in the subitizing range become comparable to those measured in the estimation range, suggesting that the estimation system works even within the subitizing range, but performance for low numbers normally augmented by the automatic deployment of visuo-spatial attentional resources 10 – 12 . The heavy reliance of subitizing on attention may therefore constitute a characteristic feature of this system and explain its higher precision.…”

Section: Introductionmentioning

confidence: 87%

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Grouping strategies in number estimation extend the subitizing range

Moscoso

Castaldi

Burr

et al. 2020

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When asked to estimate the number of items in a visual array, educated adults and children are more precise and rapid if the items are clustered into small subgroups rather than randomly distributed. This phenomenon, termed “groupitizing”, is thought to rely on the recruitment of the subitizing system (dedicated to the perception of very small numbers), with the aid of simple arithmetical calculations. The aim of current study is to verify whether the advantage for clustered stimuli does rely on subitizing, by manipulating attention, known to strongly affect attention. Participants estimated the numerosity of grouped or ungrouped arrays in condition of full attention or while attention was diverted with a dual-task. Depriving visual attention strongly decreased estimation precision of grouped but not of ungrouped arrays, as well as increasing the tendency for numerosity estimation to regress towards the mean. Additional explorative analyses suggested that calculation skills correlated with the estimation precision of grouped, but not of ungrouped, arrays. The results suggest that groupitizing is an attention-based process that leverages on the subitizing system. They also suggest that measuring numerosity estimation thresholds with grouped stimuli may be a sensitive correlate of math abilities.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 87%

Grouping strategies in number estimation extend the subitizing range

Moscoso

Castaldi

Burr

et al. 2020

Sci Rep

Self Cite

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“…Likewise, reaction-times and sensory thresholds for discriminating extremely high numerosities in the density range are elevated when participants have to respond to a visual distractor task first [42]. On the contrary, numerical discriminations in the estimation range are less affected by the deprivation of visual attentional resources [41][42][43]. A recent study has described a patient with an attentional deficit (simultagnosia) who is highly impaired in discriminating very small and very high numerosities, while thresholds for intermediate numerosities are similar to healthy controls, consistent with the notion that numerical comparisons in the estimation range can be performed with minimal reliance on attentional resources [48].…”

Section: Discussionmentioning

confidence: 99%

Fast saccadic eye-movements in humans suggest that numerosity perception is automatic and direct

et al. 2020

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Fast saccades are rapid automatic oculomotor responses to salient and ecologically important visual stimuli such as animals and faces. Discriminating the number of friends, foe, or prey may also have an evolutionary advantage. In this study, participants were asked to saccade rapidly towards the more numerous of two arrays. Participants could discriminate numerosities with high accuracy and great speed, as fast as 190 ms. Intermediate numerosities were more likely to elicit fast saccades than very low or very high numerosities. Reaction-times for vocal responses (collected in a separate experiment) were slower, did not depend on numerical range, and correlated only with the slow not the fast saccades, pointing to different systems. The short saccadic reaction-times we observe are surprising given that discrimination using numerosity estimation is thought to require a relatively complex neural circuit, with several relays of information through the parietal and prefrontal cortex. Our results suggest that fast numerosity-driven saccades may be generated on a single feed-forward pass of information recruiting a primitive system that cuts through the cortical hierarchy and rapidly transforms the numerosity information into a saccade command.

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“…Subitizing is robust, and occurs for both sequential and simultaneous stimuli, in all sensory modalities 3 , 13 – 16 . Subitizing is highly dependent on attention 17 – 24 , and seems to work in parallel with the estimation system, boosting performance at low numerosities.…”

Section: Introductionmentioning

confidence: 99%

“Groupitizing”: a strategy for numerosity estimation

Anobile

Castaldi

Moscoso

et al. 2020

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previous work has shown that when arrays of objects are grouped within clusters, participants can enumerate their numerosity more rapidly than when objects are randomly scattered, a phenomenon termed "groupitizing". importantly, the magnitude of the grouping advantage correlates with math abilities in children. Here we show that sensory precision of numerosity estimation is also improved when grouping cues are available, by up to 20%. The grouping can be induced by color and/or spatial proximity, and occurs in temporal sequences as well as spatial arrays. the improvement is strongest for participants with the highest thresholds in the random, ungrouped conditions. taken together with previous research, our data suggest that measurements correlations between numerosity estimation and formal math skills may be driven by grouping strategies, which require a minimal level of basic arithmetic. When counting is not possible, humans and other animals can rapidly estimate the number of items in any scene to achieve an approximate assessment of their numerosity. The system sustaining this ability is often termed the Approximate Number System (ANS) and, like all sensory systems, is error-prone, with errors increasing proportionally with numerosity, obeying Weber Law 1-4. Importantly, many studies have found a correlation between ANS precision (measured by Weber fraction or Coefficient of variation) and child math abilities, with lower precision associated with poorer performance in math 5-8. Children with dyscalculia, a neurodevelopmental disorder affecting mathematical and numerical learning, often show higher Weber fractions compared to typically developing children 6,9,10. Based on this evidence it has been proposed that the ANS may constitute a foundational non-symbolic system on which the language-based mathematical system could subsequently be built 6. Jevons 11 first reported that estimates of numerosities less than four are fast and error-free, subsequently termed subitizing by Kaufman and Lord 12. Subitizing is robust, and occurs for both sequential and simultaneous stimuli, in all sensory modalities 3,13-16. Subitizing is highly dependent on attention 17-24 , and seems to work in parallel with the estimation system, boosting performance at low numerosities. More recently, Starkey and McCandliss 25 suggested that subitizing mechanisms may also come into play for higher numerosities, a process they term "groupitizing". This is very much like George Miller's well-known notion of "chunking", where complex sets of information such as long telephone numbers can be more easily recalled if parsed into three or four smaller "chunks". Starkey et al. 25 measured counting speed of spatially clustered arrays in school-age children, and found that clustering, or grouping, increased performance. Crucially, both the number of clusters and the number of elements within each cluster was limited to the subitizing range (e.g. 7 = 2 + 2 + 3). Interestingly, the grouping advantage increased with age and correlated with arithmetic abil...

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Higher attentional costs for numerosity estimation at high densities

Cited by 38 publications

References 35 publications

Grouping strategies in number estimation extend the subitizing range

Grouping strategies in number estimation extend the subitizing range

Fast saccadic eye-movements in humans suggest that numerosity perception is automatic and direct

“Groupitizing”: a strategy for numerosity estimation

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