PT  - JOURNAL ARTICLE
AU  - Yul HR Kang
AU  - Anne Löffler
AU  - Danique Jeurissen
AU  - Ariel Zylberberg
AU  - Daniel M Wolpert
AU  - Michael N Shadlen
TI  - Multiple decisions about one object involve parallel sensory acquisition but time-multiplexed evidence incorporation
AID  - 10.1101/2020.10.15.341008
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.10.15.341008
4099  - http://biorxiv.org/content/early/2020/10/16/2020.10.15.341008.short
4100  - http://biorxiv.org/content/early/2020/10/16/2020.10.15.341008.full
AB  - The brain is capable of processing several streams of information that bear on different aspects of the same problem. Here we address the problem of making two decisions about one object, by studying difficult perceptual decisions about the color and motion of a dynamic random dot display. We find that the accuracy of one decision is unaffected by the difficulty of the other decision. However, the response times reveal that the two decisions do not form simultaneously. We show that both stimulus dimensions are acquired in parallel for the initial ~0.1 s but are then incorporated serially in time-multiplexed bouts. Thus there is a bottleneck that precludes updating more than one decision at a time, and a buffer that stores samples of evidence while access to the decision is blocked. We suggest that this bottleneck is responsible for the long timescales of many cognitive operations framed as decisions.