Volume 30 #4

Contents

1. Mysteries of the blind zone and cone-enriched rim at the extreme periphery of the human retina
2. Crowding-effect in the centre of the visual eld in dependence on distractors layout
3. Projectively invariant description of non-planar smooth gures. 1. Preliminary analysis of the problem
4. Comprehensive assessment of the functional suppression scotoma in patients with strabismus
5. Binocular functions developing in patients sith strabismus by means of computerized treatment of the functional suppression scotoma
6. Perception of speech intonation in russian cochlear implant users
7. Auditory discrimination of pulse intensity under forward and backward masking: absolute and relative combination of the induced peripheral reaction
8. Noise estimation for multispectral visualization
9. Gluconobacter cells and thermally expanded graphite based biosensor

In psychophysical experiments we studied the effect of surrounding objects on the recognition of low-contrast foveal test objects. The tests were Landolt rings of size of 1.1 and 1.5 deg. The distractors were similar Landolt rings or full rings without the gaps. The distance between the centers of the test and the additional objects varied from 1 to 2 diameters of the test. The observers' task was to identify the orientation of the test presented at xation. The three experiments differed in the number of distractors and their layout. In the rst experiment, only one distractor was added randomly to the left or right from the test. In the second experiment, two distractors were located symmetrically around the test and were of the same orientation. In the third experiment, the orientation of two symmetrical distractors was random. One distractor impaired recognition of the test at larger separations than did two distractors. Landolt rings were more effective than the rings without gaps. We discuss the contributions of attention and feature integration to crowding effects.

Key words: recognition, crowding-effect, Landolt ring, critical spacing, features integration, attention

References:

• Bondarko V. M., Danilova M. V., Solnushkin S. D., Chikhman V. N. Study of crowding effect for stimuli of low contrast and large sizes at the center of the visual eld // Experimental Psychology. 2015. V. 8. N 2. P. 5–20 [in Russian]
• Danilova M. V., Bondarko V. M. Context effect on the task of discrimination of the rectangular gratings orientation at the resolution limit of the visual system //Sensory Systems. 2002. V. 16. N 2. P. 100–109.
• Chung S. T.L., Levi D. M., Legge G. E. Spatial-frequency and contrast properties of crowding // Vision Res. 2001. V. 41. P. 1833–1850.
• Danilova M. V., Bondarko V. M. Foveal contour interactions and crowding effects at the resolution limit of the visual system // J. Vision. 2007. V. 7(2). P. 1–18.
• Ehrt O., Hess R. Foveal contour interaction: detection and discrimination // J. Opt. Soc. Am. A. 2005. Vol. 22. P. 209– 216.
• Flom M. C. Contour interaction and the crowding effect // Problems in Optometry. 1991. V. 3(2). P. 237–257.
• Flom M. C., Weymouth F. W., Kahneman D. Visual resolution and contour interaction //J.Opt.Soc.Am. 1963. V. 53(9). P. 1026– 1031.
• Freeman J., Chakravarthi R., Pelli D. Substitution and pooling in crowding // Atten. Percept. Psychophys. 2012. V. 74. P. 379–396.
• Hanus D., Vul E. Quantifying error distributions in crowding //J. Vision. 2013. V. 13(4). P. 1–27.
• He S., Cavanagh P., Intriligator J. Attentional resolution and the locus of visual awareness // Nature. 1996. V. 383. P. 334–336.
• Levi D. M. Crowding – an essential bottleneck for object recognition: a mini review //Vision Res. 2008. V. 48. P. 635– 649.
• Levi D. M., Klein S. A., Hariharan S. Suppressive and facilitatory spatial interactions in foveal vision: foveal crowding is simple contrast masking // J. Vision. 2002. V. 2. P. 140–166.
• Pelli D. G. Crowding: A cortical constraint on object recognition //Current opinion in neurobiology. 2008. V. 18. No 4. P. 445–451.
• Pelli D. G., Palomares M., Majaj N. J. Crowding is unlike ordinary masking: distinguishing feature detection and integration // J. Vision. 2004. V. 4. P. 1136–1169.
• Pelli D. G., Tillman K. A. The uncrowded window of object recognition // Nature Neuroscience. 2008. V. 11. P. 1129– 1135.
• Strasburger H., Harvey L. O., Rentchler I. Contrast thresholds for identi cation of numeric characters in direct and eccentric view // Percept. Psychophysics. 1991. V. 49. P. 495–508.
• Strasburger H., Rentchler I., Jüttner M. Peripheral vision and pattern recognition: a review // J. Vision. 2011. V. 11(5). P. 1–82.
• Wetherill G. B., Levitt H. Sequential estimation of points on a psychometric function // British Journal of Mathematical and Statistical Psychology. 1965. V. 18. P. 1–10.
• Woodrow H. The effect of pattern upon simultaneous letterspan //Am. J. Psychology. 1938. V. 51. P. 83–96.