Toward a multiroute model of number processing: Impaired number transcoding with preserved calculation skills.

Abstract

This article describes a patient (S. A. M.), suffering from a progressive neurological degenerative condition of unknown origin, who showed a severe difficulty in number transcoding tasks. S. A. M. could recognize and understand arabic numerals and written number names, but he could neither read them aloud nor write them. However, he had a well maintained ability to perform oral and written calculations. The striking pattern of performance observed in S. A. M. suggests that deficits affecting the ability to produce arabic or verbal numerals can be specific to particular task demands. This observation cannot be easily accommodated by current models of numerical processing. A new multiroute model for numerical processing is proposed to account for S. A. M.'s pattern of performance. This model adds asemantic transcoding pathways to the semantic processing mechanisms proposed by the M. McCloskey model.

Interacting neighbors: A connectionist model of retrieval in single-digit multiplication

“…The basic finding is that multiplication can be (doubly) dissociated from other numerical operations. For example, it can be dissociated from numerical calculation procedures , number comparison (Cipolotti & Butterworth, 1995), and subtraction (Dehaene & Cohen, 1997). Given that the semantic field is specific for multiplication, these findings are easy to incorporate into the framework presented here.…”

Simple arithmetic processing: The question of automaticity

“…For example, in production tasks, crossoperation errors occur where the incorrect solution that is produced represents the correct solution to an alternative operation involving the same operands e.g., 2 + 3 = 6 (Ashcraft, 1992;Campbell, 1987;Cipolotti & Butterworth, 1995). Likewise, in verification tasks, it takes longer to determine that a cross-operation equation is false than it does to determine that an equation with an unrelated solution (e.g., 2 + 3 = 11) is false (Ashcraft, 1992;LeFevre & Kulak, 1994;Winkelman & Schmidt, 1974;Zbrodoff & Logan, 1986).…”

Bilateral field interactions and hemispheric asymmetry in number comparison

“…[20,22,29,34,44,70,71]) in which magnitude representation plays an important role. For example, in 1992, Dehaene [29] proposed a triple-code model in which an analogical magnitude line is one of the three basic representations.…”