Decision-making with multiple alternatives

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  • A Corrigendum to this article was published on 01 July 2008


Simple perceptual tasks have laid the groundwork for understanding the neurobiology of decision-making. Here, we examined this foundation to explain how decision-making circuitry adjusts in the face of a more difficult task. We measured behavioral and physiological responses of monkeys on a two- and four-choice direction-discrimination decision task. For both tasks, firing rates in the lateral intraparietal area appeared to reflect the accumulation of evidence for or against each choice. Evidence accumulation began at a lower firing rate for the four-choice task, but reached a common level by the end of the decision process. The larger excursion suggests that the subjects required more evidence before making a choice. Furthermore, on both tasks, we observed a time-dependent rise in firing rates that may impose a deadline for deciding. These physiological observations constitute an effective strategy for handling increased task difficulty. The differences appear to explain subjects' accuracy and reaction times.

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Figure 1: Task and performance.
Figure 2: Responses of LIP neurons on the four-choice task are consistent with bounded accumulation.
Figure 3: Neural responses in the pre-motion epoch are larger on the two-choice task.
Figure 4: Neural responses during motion viewing depend on difficulty.
Figure 5: Neural responses just preceding the eye-movement responses.
Figure 6: Firing-rate excursion is larger on the four-choice task.
Figure 7: Neural responses and reaction times are inversely correlated on single trials.

Change history

  • 17 June 2008

    In the version of this article initially published, the panels in Figure 1 were mislabeled. The correct legend should be ‘Psychometric functions for the 29 experiments that included the 90° control are shown in e. Chronometric functions are shown in f ’. This error has been corrected in the HTML and PDF versions of the article.


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We thank A. Boulet, C. Lea, M. Mihali and K. Skypeck for technical assistance. This work was supported by the US National Institutes of Health (EY011378 and RR00166) and the Howard Hughes Medical Institute.

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Correspondence to Anne K Churchland.

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Churchland, A., Kiani, R. & Shadlen, M. Decision-making with multiple alternatives. Nat Neurosci 11, 693–702 (2008) doi:10.1038/nn.2123

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