Binocular contrast vision at and above threshold

Timothy S. Meese*, Mark A. Georgeson, Daniel H. Baker

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


A fundamental problem for any visual system with binocular overlap is the combination of information from the two eyes. Electrophysiology shows that binocular integration of luminance contrast occurs early in visual cortex, but a specific systems architecture has not been established for human vision. Here, we address this by performing binocular summation and monocular, binocular, and dichoptic masking experiments for horizontal 1 cycle per degree test and masking gratings. These data reject three previously published proposals, each of which predict too little binocular summation and insufficient dichoptic facilitation. However, a simple development of one of the rejected models (the twin summation model) and a completely new model (the two-stage model) provide very good fits to the data. Two features common to both models are gently accelerating (almost linear) contrast transduction prior to binocular summation and suppressive ocular interactions that contribute to contrast gain control. With all model parameters fixed, both models correctly predict (1) systematic variation in psychometric slopes, (2) dichoptic contrast matching, and (3) high levels of binocular summation for various levels of binocular pedestal contrast. A review of evidence from elsewhere leads us to favor the two-stage model. © 2006 ARVO.

Original languageEnglish
Article number7
Pages (from-to)1224-1243
Number of pages20
JournalJournal of Vision
Issue number11
Publication statusPublished - 23 Oct 2006

Bibliographical note

Creative Commons Attribution Non-Commercial No Derivatives License


  • binocular interactions
  • gain control
  • human vision
  • masking
  • model
  • psychophysics
  • summation
  • suppression


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