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SUMMARY:Perception\, action and uncertainty - Prof. Laurence Maloney\, Dep
 artment of Psychology\, NYU
DTSTART:20090119T130000Z
DTEND:20090119T140000Z
UID:TALK13316@talks.cam.ac.uk
CONTACT:John Mollon
DESCRIPTION:In executing any speeded movement\, there is uncertainty about
  the outcome due to spatial and temporal motor variability\; the actual ou
 tcome of the planned movement is typically not completely under our contro
 l.  I will first present a Bayesian decision theoretic (BDT) model of idea
 l movement planning that takes into account a subject’s own spatial and 
 temporal motor uncertainty and the rewards or penalties associated with di
 fferent movement outcomes. Then I will briefly describe two experiments de
 signed to test whether subjects take into account their own motor uncertai
 nty in planning movement. In the first experiment\, subjects are asked to 
 touch targets within  a specified time window (625 – 675 ms). Late or ea
 rly arrivals result in draconian penalties and we examine how these penalt
 ies affect subjects’ planning of movement. In the second of the two expe
 riments the subject must complete the first part of the movement with only
  partial knowledge of the actual location of the target represented as a B
 ayesian prior on possible targets. We find that subjects’ performance is
  typically close to that of a BDT ideal movement planner maximizing expect
 ed monetary reward.\nThis outcome is surprising: these motor tasks are for
 mally equivalent to decision making under risk and subjects making decisio
 ns under risk typically do not maximize expected gain. I’ll describe ver
 y recent work in which we translate classical decision making experiments 
 (concerning the Allais paradox) into motor form and directly compare decis
 ion making under risk to “movement planning under risk” in the same su
 bjects. The results suggest that\, while individuals value rewards identic
 ally in planning movement and in making economic decisions\, their use of 
 probability is markedly different. I will also present fMRI results concer
 ning the neural representation of motor uncertainty.\n\n
LOCATION:Kenneth Craik Room\, Craik-Marshall Building\, Downing Site
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