Ancient visual channels have a causal role in arithmetic calculations

Shai Gabay,William Saban,Ran R Hassin,Asael Y Sklar

doi:10.1038/s41598-021-02260-9

Shai Gabay, William Saban + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-02260-9

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Abstract

Humans exhibit complex arithmetic skills, often attributed to our exceptionally large neocortex. However, the past decade has provided ample evidence that the functional domain of the subcortex extends well beyond basic functions. Using a sensitive behavioral method, for the first time, we explored the contributions of lower-order visual monocular channels to symbolic arithmetic operations, addition and subtraction. The pattern of results from 4 different experiments provides converging evidence for a causal relation between mental arithmetic and primitive subcortical regions. The results have major implications for our understanding of the neuroevolutionary development of general numerical abilities–subcortical regions, which are shared across different species, are essential to complex numerical operations. In a bigger conceptual framework, these findings and others call for a shift from the modal view of the exclusive role of the neocortex in high-level cognition to a view that emphasizes the interplay between subcortical and cortical brain networks.

Highlights

Humans exhibit complex arithmetic skills, often attributed to our exceptionally large neocortex
In Experiment 1, we carried out a three-way analysis of variance (ANOVA) with condition (All in one-eye, Solution to a different-eye, Computational term split), operator, and distance as within-subject factors, and reaction time (RT) as the dependent variable
Follow-up planned comparisons analyses of the eye-of-origin effect revealed that the RT was significantly slower when one of the numbers in the arithmetic problem was presented to a different eye compared with the average of the two other conditions (F(1,32) = 9.38, p = 0.004, η2p=0.22, BF10 = 17.53; see Fig. 4; Accuracy: 96.3%, 95.7%, 95.8% in the computational term split, solution to a different eye, and all digits to the same eye conditions, respectively), which were not significantly different from one another (F(1,32) = 0.24, p > 0.25, BF01 = 4.8). one of the numbers

Summary

Introduction

Humans exhibit complex arithmetic skills, often attributed to our exceptionally large neocortex. The possible involvement of primitive subcortical regions, which are shared across different species, remains an open question To examine this question, we explored whether lower visual channels (subcortical and V1 regions) have a functional role in humans’ arithmetic reasoning (calculation and comparison processes). Due to the fact that symbolic arithmetic is a cultural product and a high-level cognitive function, and in accordance with the complexity of arithmetic calculations, the literature has long emphasized the involvement of mostly neocortical regions in symbolic arithmetic. It appears that areas of the neocortex play a critical role in humans’ arithmetic abilities. This overlooking of subcortical regions was previously noted and demonstrated in a review by P arvizi[15], who coined the term “corticocentric” to describe

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