fMRI evidence for a dual process account of the speed-accuracy tradeoff in decision-making.
BACKGROUND
The speed and accuracy of decision-making have a well-known trading relationship: hasty decisions are more prone to errors while careful, accurate judgments take more time. Despite the pervasiveness of this speed-accuracy trade-off (SAT) in decision-making, its neural basis is still unknown.


RESULTS
Using functional magnetic resonance imaging (fMRI) we show that emphasizing the speed of a perceptual decision at the expense of its accuracy lowers the amount of evidence-related activity in lateral prefrontal cortex. Moreover, this speed-accuracy difference in lateral prefrontal cortex activity correlates with the speed-accuracy difference in the decision criterion metric of signal detection theory. We also show that the same instructions increase baseline activity in a dorso-medial cortical area involved in the internal generation of actions.


CONCLUSIONS
These findings suggest that the SAT is neurally implemented by modulating not only the amount of externally-derived sensory evidence used to make a decision, but also the internal urge to make a response. We propose that these processes combine to control the temporal dynamics of the speed-accuracy trade-off in decision-making.
Ivanoff
Jason
J
Department of Psychology, Center for Integrative and Cognitive Neuroscience, Vanderbilt University, Nashville, Tennessee. J.Ivanoff@smu.ca
Branning
Philip
P
Marois
René
R
D000328:Adult; D001931:Brain Mapping; D003657:Decision Making; D004192:Discrimination, Psychological; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D008960:Models, Psychological; D017397:Prefrontal Cortex / Q000502:physiology; D011930:Reaction Time / Q000502:physiology*