Context Effects in Multi-Alternative Decision Making: Empirical Data and a Bayesian Model
Version of Record online: 18 JAN 2012
Copyright © 2012 Cognitive Science Society, Inc.
Volume 36, Issue 3, pages 498–516, April 2012
How to Cite
Hawkins, G., Brown, S. D., Steyvers, M. and Wagenmakers, E.-J. (2012), Context Effects in Multi-Alternative Decision Making: Empirical Data and a Bayesian Model. Cognitive Science, 36: 498–516. doi: 10.1111/j.1551-6709.2011.01221.x
- Issue online: 4 APR 2012
- Version of Record online: 18 JAN 2012
- Received 20 December 2010; received in revised form 10 May 2011; accepted 16 May 2011
- Multi-alternative choice;
- Hick's Law;
- Context effect;
- Speed–accuracy tradeoff;
- Optimal observer
For decisions between many alternatives, the benchmark result is Hick's Law: that response time increases log-linearly with the number of choice alternatives. Even when Hick's Law is observed for response times, divergent results have been observed for error rates—sometimes error rates increase with the number of choice alternatives, and sometimes they are constant. We provide evidence from two experiments that error rates are mostly independent of the number of choice alternatives, unless context effects induce participants to trade speed for accuracy across conditions. Error rate data have previously been used to discriminate between competing theoretical accounts of Hick's Law, and our results question the validity of those conclusions. We show that a previously dismissed optimal observer model might provide a parsimonious account of both response time and error rate data. The model suggests that people approximate Bayesian inference in multi-alternative choice, except for some perceptual limitations.