Psychonomic Bulletin & Review

, Volume 21, Issue 5, pp 1165–1173

The resurrection of Tweedledum and Tweedledee: Bimodality cannot distinguish serial and parallel processes

Authors

  • Paul Williams
    • University of Newcastle
    • University of Newcastle
    • School of PsychologyUniversity of Newcastle
  • James T. Townsend
    • Indiana University
Theoretical Review

DOI: 10.3758/s13423-014-0599-0

Cite this article as:
Williams, P., Eidels, A. & Townsend, J.T. Psychon Bull Rev (2014) 21: 1165. doi:10.3758/s13423-014-0599-0

Abstract

Simultaneously presented signals may be processed in serial or in parallel. One potentially valuable indicator of a system’s characteristics may be the appearance of multimodality in the response time (RT) distributions. It is known that standard serial models can predict multimodal RT distributions, but it is unknown whether multimodality is diagnostic of serial systems, or whether alternative architectures, such as parallel ones, can also make such predictions. We demonstrate via simulations that a multimodal RT distribution is not sufficient by itself to rule out parallel self-terminating processing, even with limited trial numbers. These predictions are discussed within the context of recent data indicating the existence of multimodal distributions in visual search.

Keywords

ParallelSerialResponse timesBimodality

Copyright information

© Psychonomic Society, Inc. 2014