Feature-based integration of orientation signals in visual search

We have measured orientation discrimination in the presence of a variable number of neutral distracters for two distinct tasks: identification of the orientation of a tilted target and location of its position. Both tasks were performed in the presence of visual noise of variable contrasts. Under a range of conditions, subjects could identify the direction of target tilt at thresholds well below those necessary to locate its position. The location thresholds showed only weak dependency on set-size, consistent with a stimulus uncertainty of parallel search of the output of independent orientation analysers, while the identification thresholds showed a much stronger dependency, varying with the square root of set-size over a wide range noise contrasts. The square root relationship suggests perceptual summation of target and distracters. Manipulating the spread of visual noise suggests that the summation is feature-based, possibly operating on the outputs of first-stage orientation analysers. Pre-cueing the target eliminates the effects of set-size, showing that the summation is under rapid attentional control; the visual system can choose between high performance over a limited area and poorer performance over a much larger area.

[1]  R. Watt,et al.  The computation of orientation statistics from visual texture , 1997, Vision Research.

[2]  M. Morgan,et al.  Visual Search for a Tilted Target: Tests of Spatial Uncertainty Models , 1998, The Quarterly journal of experimental psychology. A, Human experimental psychology.

[3]  M. Morgan,et al.  Contrast discrimination function: spatial cuing effects. , 1997, Journal of the Optical Society of America. A, Optics, image science, and vision.

[4]  R. Parasuraman.  The attentive brain , 1998 .

[5]  J. Palmer,et al.  Measuring the effect of attention on simple visual search. , 1993, Journal of experimental psychology. Human perception and performance.

[6]  U. Neisser.  VISUAL SEARCH. , 1964, Scientific American.

[7]  C. Gilbert.  Horizontal integration in the neocortex , 1985, Trends in Neurosciences.

[8]  Colin Blakemore,et al.  Vision: Coding and Efficiency , 1991 .

[9]  D. Foster,et al.  Limitations of rapid parallel processing in the detection of long and short oriented line targets. , 1999, Spatial vision.

[10]  J. Duncan.  Selective attention and the organization of visual information. , 1984, Journal of experimental psychology. General.

[11]  J. S. Wright,et al.  The oblique effect in orientation acuity , 1997, Vision Research.

[12]  A. Watson,et al.  Quest: A Bayesian adaptive psychometric method , 1983, Perception & psychophysics.

[13]  P. Verghese,et al.  Combining speed information across space , 1995, Vision Research.

[14]  M. Cheal,et al.  Allocation of Attention in Texture Segregation, Visual Search, and Location-Precuing Paradigms , 1994, The Quarterly journal of experimental psychology. A, Human experimental psychology.

[15]  A. Treisman.  Perceptual grouping and attention in visual search for features and for objects. , 1982, Journal of experimental psychology. Human perception and performance.

[16]  James R. Bergen,et al.  Parallel versus serial processing in rapid pattern discrimination , 1983, Nature.

[17]  John Duncan,et al.  Objects and attributes in divided attention: Surface and boundary systems , 1996, Perception & psychophysics.

[18]  M. Eckstein.  The Lower Visual Search Efficiency for Conjunctions Is Due to Noise and not Serial Attentional Processing , 1998 .

[19]  Ken Nakayama,et al.  Attentional requirements in a ‘preattentive’ feature search task , 1997, Nature.

[20]  U. Neisser.  Decision-time without reaction-time: Experiments in visual scanning. , 1963 .

[21]  C. Koch,et al.  Attention activates winner-take-all competition among visual filters , 1999, Nature Neuroscience.

[22]  J. Palmer.  Set-size effects in visual search: The effect of attention is independent of the stimulus for simple tasks , 1994, Vision Research.

[23]  D G Pelli,et al.  Uncertainty explains many aspects of visual contrast detection and discrimination. , 1985, Journal of the Optical Society of America. A, Optics and image science.

[24]  J. Duncan,et al.  Visual search and stimulus similarity. , 1989, Psychological review.

[25]  Stefan Treue,et al.  Feature-based attention influences motion processing gain in macaque visual cortex , 1999, Nature.

[26]  J. Duncan.  Boundary Conditions on Parallel Processing in Human Vision , 1989, Perception.

[27]  B. Dosher,et al.  External noise distinguishes attention mechanisms , 1998, Vision Research.

[28]  D. Pelli.  The quantum efficiency of vision , 1990 .

[29]  D. Regan,et al.  Postadaptation orientation discrimination. , 1985, Journal of the Optical Society of America. A, Optics and image science.

[30]  J. Duncan.  Selective attention and the organization of visual information , 1984 .

[31]  Sir G. Archaeopteryx.  Object-based attention in the primary visual cortex of the macaque monkey , 1998 .

[32]  Pieter R. Roelfsema,et al.  Object-based attention in the primary visual cortex of the macaque monkey , 1998, Nature.

[33]  K. Nakayama,et al.  Stimulus discriminability in visual search , 1994, Vision Research.

[34]  K. Nakayama,et al.  Attention, pattern recognition and popout in visual search , 1998 .

[35]  M. Carrasco,et al.  The contribution of covert attention to the set-size and eccentricity effects in visual search. , 1998, Journal of experimental psychology. Human perception and performance.

[36]  C. Gilbert,et al.  Attention and Perceptual Learning Modulate Contextual Influences on Visual Perception , 1998, Neuron.

[37]  Preeti Verghese,et al.  The psychophysics of visual search , 2000, Vision Research.

[38]  D W Heeley,et al.  Anisotropic Axes in Orientation Perception are Not Retinotopically Mapped , 1993, Perception.