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Magnitudes in the human brain : independent processing of time, space and number

Abstract : If you want to catch your train on time you have to estimate how far the station is from your current position and how long it will take you to go there. A growing body of evidence suggests that interferences may exist in the perception of different magnitude dimensions. These relationships fascinate researchers for decades and led Walsh (2003) to hypothesize that Time, Space and Number were part of a generalized magnitude system which may be located in the parietal cortex. In this thesis, we first investigated the possible existence of such system. Manipulating non-temporal magnitude dimensions did not interfere with duration judgments. Instead, numerical and spatial estimates were biased when we manipulated the rate of accumulation of sensory evidence. In this first experiment we asked whether a generalized Bayesian magnitude estimation system would sample evidence using a common, amodal prior, as expected by a generalized magnitude system. Our results suggested that from a Bayesian perspective, computations would necessitate multiple priors. This work provides substantial evidence against the existence of a generalized magnitude system. To further investigate interferences of numerical magnitude on perceived duration, we built a second experiment in which participants were required to reproduce intervals of time and also judge the numerical magnitude of the stimulus. Our results revealed that the number-time interaction depended on the numerical format that was used. Our work suggests that the numerical magnitude is automatically processed at a non-symbolic level whereas it requires attentional resources when numerical information is symbolically conveyed.
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Submitted on : Friday, April 6, 2018 - 10:08:08 AM
Last modification on : Tuesday, November 16, 2021 - 4:04:22 AM


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  • HAL Id : tel-01760214, version 1


Benoît Martin. Magnitudes in the human brain : independent processing of time, space and number. Cognitive Sciences. Université Pierre et Marie Curie - Paris VI, 2017. English. ⟨NNT : 2017PA066417⟩. ⟨tel-01760214⟩



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