University Of Tasmania

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Distinguishing the time-­ and magnitude-­difference accounts of the Simon Effect: Evidence from the reach-to-touch paradigm

journal contribution
posted on 2023-05-18, 15:03 authored by Finkbeiner, M, Heathcote, A
A Simon effect occurs when the irrelevant spatial attributes of a stimulus conflict with choice responses based on non-spatial stimulus attributes. Many theories of the Simon effect assume that activation from task-irrelevant spatial attributes becomes available before the activation from task-relevant attributes. We refer to this as the time-difference account. Other theories follow a magnitude-difference account, assuming activation from relevant and irrelevant attributes becomes available at the same time, but with the activation from irrelevant attributes initially being stronger. To distinguish these two accounts, we incorporated the response-signal procedure into the reach-to-touch paradigm to map out the emergence of the Simon effect. We also used a carefully calibrated neutral condition to reveal differences in the initial onset of the influence of relevant and irrelevant information. Our results establish that irrelevant spatial information becomes available earlier than relevant non-spatial information. This finding is consistent with the time-difference account and inconsistent with the magnitude-difference account. However, we did find a magnitude effect, in the form of reduced interference from irrelevant information, for the second of a sequence of two incongruent trials.


Publication title

Attention, Perception & Psychophysics








Tasmanian School of Medicine


Springer New York LLC

Place of publication

United States

Rights statement

Copyright The Psychonomic Society, Inc. 2015

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  • Restricted

Socio-economic Objectives

Expanding knowledge in psychology

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