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Similarity and number of alternatives in the random-dot motion paradigm
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 disenta...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Springer-Verlag
2012
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3310993/ https://www.ncbi.nlm.nih.gov/pubmed/22287207 http://dx.doi.org/10.3758/s13414-011-0267-7 |
Sumario: | 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. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.3758/s13414-011-0267-7) contains supplementary material, which is available to authorized users. |
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