Paradoxical evidence integration in rapid decision processes

PLoS Comput Biol. 2012;8(2):e1002382. doi: 10.1371/journal.pcbi.1002382. Epub 2012 Feb 16.


Decisions about noisy stimuli require evidence integration over time. Traditionally, evidence integration and decision making are described as a one-stage process: a decision is made when evidence for the presence of a stimulus crosses a threshold. Here, we show that one-stage models cannot explain psychophysical experiments on feature fusion, where two visual stimuli are presented in rapid succession. Paradoxically, the second stimulus biases decisions more strongly than the first one, contrary to predictions of one-stage models and intuition. We present a two-stage model where sensory information is integrated and buffered before it is fed into a drift diffusion process. The model is tested in a series of psychophysical experiments and explains both accuracy and reaction time distributions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Algorithms
  • Computational Biology / methods
  • Decision Making*
  • Diffusion
  • Discrimination, Psychological
  • Female
  • Humans
  • Male
  • Observer Variation
  • Reaction Time
  • Reproducibility of Results
  • Software
  • Time Factors