Pupil Dilation

The size of the pupil is constantly changing. These changes can reflect an increase/decrease in light levels and also changing levels of noradrenaline in the brain associated with thoughts and emotions. We are particularly interested in the use of pupil dilation to investigate the role of noradrenaline and arousal in decision making. We are also exploring ways to use this signal to communicate with people suffering from severe motor paralysis.

Journal Articles


  • Stoll, J., Chatelle, C., Carter, O., Koch, C., Laureys, S., & Einhäuser, W. (2013). Pupil responses allow communication in locked-in syndrome patients. Current Biology 23(15), R647–8. [PDF]
  • Naber, M., Stoll, J., Einhäuser, W., & Carter, O. (2013). How to become a mentalist: reading decisions from a competitor's pupil can be achieved without training but requires instruction. PLoS One 8(8), e73302. [PDF]


  • Einhäuser, W., Koch, C. & Carter, O. (2010) Pupil dilation betrays the timing of decisions. Front Human Neurosci 4(18): 1-9. [PDF]


  • Einhäuser, W., Stout, J., Koch, C. & Carter, O. (2008) Pupil dilation reflects perceptual selection and predicts subsequent stability in perceptual rivalry. Proc Natl Acad Sci 105(5): 1704-09. [PDF]