Principles of feature integration in visual perception.

Several recent theories of visual information processing have postulated that errors in recognition may result not only from a failure in feature extraction, but also from a failure to correctly join features after they have been correctly extracted. Errors that result from incorrectly integrating features are called conjunction errors. The present study uses conjunction errors to investigate the principles used by the visual system to integrate features. The research tests whether the visual system is more likely to integrate features located close together in visual space (the location principle} or whether the visual system is more likely to integrate feature,s from stimulus items that come from the same perceptual group or object {the perceptual group principle}. In four target-detection experiments, stimuli were created so that feature integration by the location principle and feature integration by the perceptual group principle made diffe:cent predictions for performance. In all of the experiments, the perceptual group principle pr~ dicted feature integration even though the distance between stimulus items and retinal eccentricity were strictly controlled.