Research: Seeing is not believing

27 February 2006

In virtual reality experiments, the brain refuses to believe that a room might change in size.

Our visual system enables us to create a representation of the three-dimensional world in our heads. This stored information is constantly updated as we move.

Previous work has shown that the visual system takes account of the distance we have moved and the separation of our eyes when judging the scale and shape of objects and how far away they are.

But using a Wellcome Trust-funded immersive virtual reality suite at the University of Oxford, Dr Andrew Glennerster and colleagues found that our normal 3D vision systems (binocular stereopsis and depth from motion parallax) fail to detect that a room has expanded or contracted.

Subjects were shown a cube on one side of the virtual scene, then the room was expanded or contracted and a similar cube was shown on the other side of the room. All subjects consistently misjudged the relative sizes of the cubes, automatically assuming that the room had stayed the same size.

The researchers suggest that we are far more willing to adjust estimates of distance walked or separation of our eyes than to accept that a scene has changed in size.

External links

• Glennerster A et al. Humans ignore motion and stereo cues in favor of a fictional stable world. Curr Biol 2006;16(4):428–32.