Australasian Mathematical Psychology Conference 2019

Control failures in Simon and Flanker Tasks

Andrew Heathcote
Psychology, University of Tasmania
Dora Matzke
University of Amsterdam

We examine the complete failure of control within the Conflict LBA model, which explains conflict in Stroop, Simon and Flanker tasks in terms of priming and the control deployed to counter the misleading effects of priming. A key concept for the model is that control is variable, sometimes undercompensating and sometimes overcompensating for priming. Within the context of the Conflict LBA model, we extended MacLeod and MacDonald’s (2000) “inadvertent reading hypothesis” for the Stroop task, that occasional reading rather than colour naming responses explain some portion of incongruent errors and speeding in correct congruent responses, to Simon task data, collected by Forstman, van den Wildenberg and Ridderinkhof (2008), and Flanker data, collected by White, Ratcliff and Starns (2011). Although the probability of complete failures to exercise any control on some trials, causing participants to perform the wrong task (e.g., responding based on location in the Simon task or to the Flankers in the Flanker task), was relatively small, such failures were key to explaining the detailed shapes of conditional-accuracy functions. In the Flanker task, failure probability was found to increase systematically as the proportion of incongruent trials in each block decreased. Estimations issues and the relationships among the parameters of the extended Conflict LBA are discussed.

Forstmann, B. U., van den Wildenberg, W. P., & Ridderinkhof, K. R. (2008). Neural mechanisms, temporal dynamics, and individual differences in interference control. Journal of Cognitive Neuroscience, 20(10), 1854–1865.
MacLeod, C. M., & MacDonald, P. A. (2000). Interdimensional interference in the Stroop effect: Uncovering the cognitive and neural anatomy of attention. Trends in Cognitive Sciences, 4(10), 383–391.
White, C. N., Ratcliff, R., & Starns, J. J. (2011). Diffusion models of the flanker task: Discrete versus gradual attentional selection. Cognitive Psychology, 63(4), 210-238.