Neither here nor there: localizing conflicting visual attributes.

Natural visual scenes are a rich source of information. Objects often carry luminance, colour, motion, depth and textural cues, each of which can serve to aid detection and localization of the object within a scene. Contemporary neuroscience presumes a modular approach to visual analysis in which each of these attributes are processed within ostensibly independent visual streams and are transmitted to geographically distinct and functionally dedicated centres in visual cortex (van Essen & Maunsell, 1983; Zihl, von Cramon & Mai, 1983; Maunsell & Newsome, 1987; Tootell, Hadjikhani, Mendola, Marrett & Dale, 1998). In the present study we ask how the visual system localizes objects within this framework. Specifically, we investigate how the visual system assigns a unitary location to objects defined by multiple stimulus attributes, where such attributes provide conflicting positional cues. The results show that conflicting sources of visual information can be effortlessly combined to form a global estimate of spatial position, yet, this conflation of visual attributes is achieved at a cost to localization accuracy. Furthermore, our results suggest that the visual system assigns more perceptual weight (Landy, 1993; Landy & Kojima, 2001) to visual attributes which are reliably related to object contours.

[1]  M. J. Morgan,et al.  Motion displacement thresholds for compound stimuli predicted by the displacement of centroids , 1994, Vision Research.

[2]  J J Knierim,et al.  Neural responses to visual texture patterns in middle temporal area of the macaque monkey. , 1992, Journal of neurophysiology.

[3]  D. Levi,et al.  The influence of adaptation on perceived visual location , 1997, Vision Research.

[4]  S. Grossberg,et al.  Neural dynamics of form perception: boundary completion, illusory figures, and neon color spreading. , 1985 .

[5]  H. Wilson,et al.  Fourier and Non-Fourier Pattern Discrimination Compared , 1996, Vision Research.

[6]  D. Badcock,et al.  Global-motion Perception: Interaction of Chromatic and Luminance Signals , 1996, Vision Research.

[7]  J. C. Meadows,et al.  Cerebral color blindness: An acquired defect in hue discrimination , 1979, Annals of neurology.

[8]  R. J. Watt,et al.  Mechanisms responsible for the assessment of visual location: Theory and evidence , 1983, Vision Research.

[9]  I Mareschal,et al.  Cortical processing of second-order motion , 1999, Visual Neuroscience.

[10]  M. Landy,et al.  Measurement and modeling of depth cue combination: in defense of weak fusion , 1995, Vision Research.

[11]  D. Hubel,et al.  Segregation of form, color, movement, and depth: anatomy, physiology, and perception. , 1988, Science.

[12]  Andrew T. Smith,et al.  Evidence for separate motion-detecting mechanisms for first- and second-order motion in human vision , 1994, Vision Research.

[13]  John H. R. Maunsell,et al.  Hierarchical organization and functional streams in the visual cortex , 1983, Trends in Neurosciences.

[14]  George Mather,et al.  Depth cue integration: stereopsis and image blur , 2000, Vision Research.

[15]  M. Just,et al.  Cognitive coordinate systems: accounts of mental rotation and individual differences in spatial ability. , 1985, Psychological review.

[16]  DAVID WHITAKER,et al.  Centroid Analysis Predicts Visual Localization of First- and Second-order Stimuli , 1996, Vision Research.

[17]  H. Wilson,et al.  A psychophysically motivated model for two-dimensional motion perception , 1992, Visual Neuroscience.

[18]  Denis G. Pelli,et al.  Accurate control of contrast on microcomputer displays , 1991, Vision Research.

[19]  G. Sperling,et al.  Drift-balanced random stimuli: a general basis for studying non-Fourier motion perception. , 1988, Journal of the Optical Society of America. A, Optics and image science.

[20]  M. Morgan,et al.  Efficiency of locating centres of dot-clusters by human observers , 1991, Vision Research.

[21]  Isabelle Mareschal,et al.  A cortical locus for the processing of contrast-defined contours , 1998, Nature Neuroscience.

[22]  A. Derrington,et al.  Discriminating the direction of second-order motion at short stimulus durations , 1993, Vision Research.

[23]  D R Badcock,et al.  Independent first- and second-order motion energy analyses of optic flow , 2001, Psychological research.

[24]  Patrick Cavanagh,et al.  Interattribute apparent motion , 1989, Vision Research.

[25]  A. Dale,et al.  From retinotopy to recognition: fMRI in human visual cortex , 1998, Trends in Cognitive Sciences.

[26]  J. Movshon,et al.  Spatial summation in the receptive fields of simple cells in the cat's striate cortex. , 1978, The Journal of physiology.

[27]  D. Hubel,et al.  Receptive fields, binocular interaction and functional architecture in the cat's visual cortex , 1962, The Journal of physiology.

[28]  Josée Rivest,et al.  Localizing contours defined by more than one attribute , 1996, Vision Research.

[29]  David R. Badcock,et al.  Detecting the displacement of periodic patterns , 1985, Vision Research.

[30]  D. V. van Essen,et al.  Antibody labeling of functional subdivisions in visual cortex: Cat-301 immunoreactivity in striate and extrastriate cortex of the macaque monkey , 1990, Visual Neuroscience.

[31]  Norma Graham,et al.  Nonlinear processes in spatial-frequency channel models of perceived texture segregation: Effects of sign and amount of contrast , 1992, Vision Research.

[32]  S. Shipp,et al.  The functional logic of cortical connections , 1988, Nature.

[33]  Suzanne P. McKee,et al.  Integration regions for visual hyperacuity , 1977, Vision Research.

[34]  M J Morgan,et al.  Vernier acuity predicted from changes in the light distribution of the retinal image. , 1985, Spatial vision.

[35]  M. Morgan,et al.  What direction of motion do we see if luminance but not colour contrast is reversed during displacement? psychophysical evidence for a signed-colour input to motion detection , 1994, Vision Research.

[36]  D. Regan,et al.  Vernier step acuity and bisection acuity for texture-defined form , 1997, Vision Research.

[37]  M. J. Morgan,et al.  Stereo and motion disparities interfere with positional averaging , 1993, Vision Research.

[38]  A. Damasio,et al.  Central achromatopsia , 1980, Neurology.

[39]  David Whitaker,et al.  Spatial characteristics of the second-order visual pathway revealed by positional adaptation , 1999, Nature Neuroscience.

[40]  R. Shapley.  Linearity and non-linearity in cortical receptive fields. , 1994, Ciba Foundation symposium.

[41]  N. Mai,et al.  Selective disturbance of movement vision after bilateral brain damage. , 1983, Brain : a journal of neurology.

[42]  M. J. Morgan,et al.  Positional acuity with chromatic stimuli , 1985, Vision Research.

[43]  C L Baker,et al.  A processing stream in mammalian visual cortex neurons for non-Fourier responses. , 1993, Science.

[44]  M S Landy,et al.  Ideal cue combination for localizing texture-defined edges. , 2001, Journal of the Optical Society of America. A, Optics, image science, and vision.