- Title
- Similarity and number of alternatives in the random-dot motion paradigm
- Creator
- van Maanen, Leendert; Grasman, Raoul P. P. P.; Forstmann, Birte U.; Keuken, Max C.; Brown, Scott D.; Wagenmakers, Eric-Jan
- Relation
- Attention Perception & Psychophysics Vol. 74, Issue 4, p. 739-753
- Publisher Link
- http://dx.doi.org/10.3758/s13414-011-0267-7
- Publisher
- Springer
- Resource Type
- journal article
- Date
- 2012
- Description
- The popular random-dot motion (RDM) task has recently been applied to multiple-choice perceptual decision-making. However, changes in the number of alternatives on an RDM display lead to changes in the similarity between the alternatives, complicating the study of multiple-choice effects. To disentangle the effects of similarity and number of alternatives, we analyzed behavior in the RDM task using an optimal-observer model. The model applies Bayesian principles to give an account of how changes in the stimulus influence the decision-making process. A possible neural implementation of the optimal-observer model is discussed, and we provide behavioral data that support the model. We verify the predictions from the optimal-observer model by fitting a descriptive model of choice behavior (the linear ballistic accumulator model) to the behavioral data. The results show that (a) there is a natural interaction in the RDM task between similarity and the number of alternatives; (b) the number of alternatives influences “response caution”, whereas the similarity between the alternatives influences “drift rate”; and (c) decisions in the RDM task are near optimal when participants are presented with multiple alternatives.
- Subject
- Bayesian modeling; decision making; response time models
- Identifier
- http://hdl.handle.net/1959.13/1302218
- Identifier
- uon:20433
- Identifier
- ISSN:1943-3921
- Language
- eng
- Full Text
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