RT Journal Article
SR Electronic
T1 The Cost of Accumulating Evidence in Perceptual Decision Making
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 3612
OP 3628
DO 10.1523/JNEUROSCI.4010-11.2012
VO 32
IS 11
A1 Drugowitsch, Jan
A1 Moreno-Bote, Rubén
A1 Churchland, Anne K.
A1 Shadlen, Michael N.
A1 Pouget, Alexandre
YR 2012
UL http://www.jneurosci.org/content/32/11/3612.abstract
AB Decision making often involves the accumulation of information over time, but acquiring information typically comes at a cost. Little is known about the cost incurred by animals and humans for acquiring additional information from sensory variables due, for instance, to attentional efforts. Through a novel integration of diffusion models and dynamic programming, we were able to estimate the cost of making additional observations per unit of time from two monkeys and six humans in a reaction time (RT) random-dot motion discrimination task. Surprisingly, we find that the cost is neither zero nor constant over time, but for the animals and humans features a brief period in which it is constant but increases thereafter. In addition, we show that our theory accurately matches the observed reaction time distributions for each stimulus condition, the time-dependent choice accuracy both conditional on stimulus strength and independent of it, and choice accuracy and mean reaction times as a function of stimulus strength. The theory also correctly predicts that urgency signals in the brain should be independent of the difficulty, or stimulus strength, at each trial.