A Caltech Library Service

Pupil dilation betrays the timing of decisions

Einhäuser, Wolfgang and Koch, Christof and Carter, Olivia (2010) Pupil dilation betrays the timing of decisions. Frontiers in Human Neuroscience, 4 . Art. no. 18. ISSN 1662-5161. PMCID PMC2831633. doi:10.3389/fnhum.2010.00018.

PDF - Published Version
See Usage Policy.


Use this Persistent URL to link to this item:


The notion of “mind-reading” by carefully observing another individual’s physiological responses has recently become commonplace in popular culture, particularly in the context of brain imaging. The question remains, however, whether outwardly accessible physiological signals indeed betray a decision before a person voluntarily reports it. In one experiment we asked observers to push a button at any time during a 10-s period (“immediate overt response”). In a series of three additional experiments observers were asked to select one number from five sequentially presented digits but concealed their decision until the trial’s end (“covert choice”). In these experiments observers either had to choose the digit themselves under conditions of reward and no reward, or were instructed which digit to select via an external cue provided at the time of the digit presentation. In all cases pupil dilation alone predicted the choice (timing of button response or chosen digit, respectively). Consideration of the average pupil-dilation responses, across all experiments, showed that this prediction of timing was distinct from a general arousal or reward-anticipation response. Furthermore, the pupil dilation appeared to reflect the post-decisional consolidation of the selected outcome rather than the pre-decisional cognitive appraisal component of the decision. Given the tight link between pupil dilation and norepinephrine levels during constant illumination, our results have implications beyond the tantalizing mind-reading speculations. These findings suggest that similar noradrenergic mechanisms may underlie the consolidation of both overt and covert decisions.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle CentralPubMed article
Koch, Christof0000-0001-6482-8067
Additional Information:Copyright: © 2010 Einhäuser, Koch and Carter. This is an open-access article subject to an exclusive license agreement between the authors and the Frontiers Research Foundation, which permits unrestricted use, distribution, and reproduction in any medium, provided the original authors and source are credited. Received: 18 August 2009; paper pending published: 30 September 2009; accepted: 10 February 2010; published online: 26 February 2010. This research was funded by the Mathers Foundation to Christof Koch and NHMRC(Aust) grant-no.: 368525 to Olivia L. Carter.
Group:Koch Laboratory (KLAB)
Funding AgencyGrant Number
Mathers FoundationUNSPECIFIED
Subject Keywords:decision-making, cognition, behavior, pupil, norepinephrine
PubMed Central ID:PMC2831633
Record Number:CaltechAUTHORS:20130816-103358705
Persistent URL:
Official Citation:Einhäuser W, Koch C and Carter. LO (2010) Pupil dilation betrays the timing of decisions. Front. Hum. Neurosci. 4:18. doi: 10.3389/fnhum.2010.00018
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:40677
Deposited By: KLAB Import
Deposited On:10 Feb 2012 23:20
Last Modified:10 Nov 2021 00:07

Repository Staff Only: item control page