Feature analysis in early vision: evidence from search asymmetries.

  title={Feature analysis in early vision: evidence from search asymmetries.},
  author={Anne Treisman and Stephen P. Gormican},
  journal={Psychological review},
  volume={95 1},
In this article we review some new evidence relating to early visual processing and propose an explanatory framework. A series of search experiments tested detection of targets distinguished from the distractors by differences on a single dimension. Our aim was to use the pattern of search latencies to infer which features are coded automatically in early vision. For each of 12 different dimensions, one or more pairs of contrasting stimuli were tested. Each member of a pair played the role of… 

Asymmetries in visual search: An introduction

  • J. Wolfe
  • Psychology
    Perception & psychophysics
  • 2001
Four of the eight papers in this symposium inPerception & Psychophysics deal with the use of search asymmetries to identify stimulus attributes that behave as basic features in this context, and another two deals with the long-standing question of whether a novelty can be considered to be a basic feature.

Efficient visual search by category: Specifying the features that mark the difference between artifacts and animals in preattentive vision

It is argued that existing theories are helpful in understanding these findings but that they need to be supplemented to account for the specific features that specify categories and to accounts for subjects’ ability to quickly locate targets representing heterogeneous and formally complex categories.

Some evidence for unequal loss of location and feature information as a function of retinal eccentricity in visual search

Abstract Several psychophysical studies suggest that the quality of feature and positional information deteriorates differentially as a function of retinal eccentricity. Nevertheless, current models

Visual search in peripheral vision: learning effects and set-size dependence.

The hemifield preference effect seems related to competition, and perhaps an automatic attention-directing mechanism, and the central presentation set-size independence for feature search was confirmed but found a great difference between large and small arrays when presentation was lateral.

Orientation-selective summing mechanisms revealed in visual search

Visual Representation Determines Search Difficulty: Explaining Visual Search Asymmetries

It is demonstrated that distinct classes of asymmetries may be explained by virtue of a few simple conditions that are consistent with current thinking surrounding computational modeling of visual search and coding in the primate brain.

A diffusion model of early visual search: Theoretical analysis and experimental results

A diffusion model of early visual-search processes that quantitatively describes this evolution of attention in time and space is presented, based on a genuine relation between the spatial and temporal dimensions of the search processes performed.

Are shape differences detected in early vision?

A series of visual search experiments explored whether early visual processes are sensitive to the overall shape of objects. Previous work (Wolfe & Bennett, 1997) has suggested that information

Visual search at different spatial scales.

  • J. Saarinen
  • Psychology
    Scandinavian journal of psychology
  • 1995
In the experiments reported here, the processing of feature conjunctions was studied when the stimulus features of a combination were at different spatial scales, and it is possible that the conjunction search could not be performed in parallel because switches between the two scales are linked to attention and the task required the use of both scales in order to find the target.

Visual search near threshold: Some features are more equal than others.

Accuracy in feature search is a good predictor of accuracy in conjunction search for color but not for size and orientation, and the use of conjunctively tuned channels and differential crowding effects for different features are proposed.



Search asymmetry: a diagnostic for preattentive processing of separable features.

Results are consistent with feature-integration theory, which predicts that a single feature should be detected by the mere presence of activity in the relevant feature map, whereas tasks that require subjects to locate multiple instances of a feature demand focused attention.

Preattentive processing in vision

  • A. Treisman
  • Psychology
    Comput. Vis. Graph. Image Process.
  • 1985

Serial and parallel processing of visual feature conjunctions

It seems that the visual system is incapable of conducting a parallel search over two stimulus dimensions simultaneously, but this conclusion is extended for the conjunction of motion and colour, showing that it requires a serial search.

Searching for conjunctively defined targets.

In an experiment in which the numbers of the two distractors were unconfounded, evidence is found that subjects can search through specified subsets of stimuli, and implications of selective search are discussed.

Detection versus Discrimination of Visual Orientation

The role of focused attention in vision is examined and experiments show that the mixture of a few horizontal and vertical line segments embedded in an aggregate of diagonal line segments can be rapidly counted by a parallel (preattentive) process, while the discrimination between horizontal and Vertical orientation requires serial search by shifting focal attention to each line segment.

Conjunction of color and form without attention: evidence from an orientation-contingent color aftereffect.

  • M. HouckJ. Hoffman
  • Psychology
    Journal of experimental psychology. Human perception and performance
  • 1986
Color and shape appear to be conjoined preattentively, when perceptual aftereffects are used as the measure, and different experimental procedures may be tapping into different stages of preatTentive vision.

A feature-integration theory of attention

Perceptual grouping and attention in visual search for features and for objects.

  • A. Treisman
  • Psychology
    Journal of experimental psychology. Human perception and performance
  • 1982
The effects of perceptual grouping on search for targets defined by separate features or by conjunction of features is explored, suggesting that preattentive grouping creates separate feature maps within each separable dimension rather than one global configuration.

Perception of wholes and of their component parts: some configural superiority effects.

Two patterns which differed only in a single part could be discriminated from each other more quickly than could their distinguishing parts shown in isolation, and the outlines of a model for preattentive feature discrimination are presented.

Principles of feature integration in visual perception

The research tests whether the visual system is more likely to integrate features located close together in visual space (the location principle) or whether theVisual system isMore likely to integrating features from stimulus items that come from the same perceptual group or object (the perceptual group principle).