Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Perspective
  • Published:

The uncrowded window of object recognition

Nature Neuroscience volume 11, pages 1129–1135 (2008)Cite this article

An Erratum to this article was published on 01 December 2008

This article has been updated

Abstract

It is now emerging that vision is usually limited by object spacing rather than size. The visual system recognizes an object by detecting and then combining its features. 'Crowding' occurs when objects are too close together and features from several objects are combined into a jumbled percept. Here, we review the explosion of studies on crowding—in grating discrimination, letter and face recognition, visual search, selective attention, and reading—and find a universal principle, the Bouma law. The critical spacing required to prevent crowding is equal for all objects, although the effect is weaker between dissimilar objects. Furthermore, critical spacing at the cortex is independent of object position, and critical spacing at the visual field is proportional to object distance from fixation. The region where object spacing exceeds critical spacing is the 'uncrowded window'. Observers cannot recognize objects outside of this window and its size limits the speed of reading and search.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: An A in chaff.
Figure 2: Effects of crowding.
Figure 3: Crowding in a word.
Figure 4: Faces are like words.
Figure 5: Critical spacing is independent of object and size.
Figure 6: Critical spacing is proportional to eccentricity.
Figure 7: What is your uncrowded span?
Figure 8: The uncrowded window.
Figure 9: Reading speed versus span.
Figure 10: The Rey Complex Figure Test.

Similar content being viewed by others

Change history

  • 13 November 2008

    In the version of this article initially published, the legend to Figure 5 contained several errors. The second sentence should read “Fixating on the red minus, you will be unable to identify the middle object in the first eight rows unless you isolate it by hiding the flanking objects with your fingers (or two pencils). ” The fourth sentence should read “Grating patches, similar to those in the top row, are often taken to be one-feature objects. ” These errors have been corrected in the HTML and PDF versions of the article.

References

  1. Barlow, H.B. Summation and inhibition in the frog's retina. J. Physiol. (Lond.) 119, 69–88 (1953).

    Article  CAS  Google Scholar 

  2. Robson, J.G. & Graham, N. Probability summation and regional variation in contrast sensitivity across the visual field. Vision Res. 21, 409–418 (1981).

    Article  CAS  Google Scholar 

  3. Treisman, A.M. & Gelade, G. A feature-integration theory of attention. Cognit. Psychol. 12, 97–136 (1980).

    Article  CAS  Google Scholar 

  4. Pelli, D.G., Burns, C.W., Farell, B. & Moore-Page, D.C. Feature detection and letter identification. Vision Res. 46, 4646–4674 (2006).

    Article  Google Scholar 

  5. Hubel, D.H. & Wiesel, T.N. Receptive fields, binocular interaction and functional architecture in the cat's visual cortex. J. Physiol. (Lond.) 160, 106–154 (1962).

    Article  CAS  Google Scholar 

  6. Desimone, R. & Duncan, J. Neural mechanisms of selective visual attention. Annu. Rev. Neurosci. 18, 193–222 (1995).

    Article  CAS  Google Scholar 

  7. Ullman, S. High-Level Vision: Object Recognition and Visual Cognition (MIT Press, Cambridge, Massachusetts, 2000).

    Google Scholar 

  8. Parkes, L., Lund, J., Angelucci, A., Solomon, J.A. & Morgan, M. Compulsory averaging of crowded orientation signals in human vision. Nat. Neurosci. 4, 739–744 (2001).

    Article  CAS  Google Scholar 

  9. Motter, B.C. Crowding and object integration within the receptive field of V4 neurons. J. Vis. 2:274, 247a (2002).

    Google Scholar 

  10. Ledgeway, T., Hess, R.F. & Geisler, W.S. Grouping local orientation and direction signals to extract spatial contours: empirical tests of “association field” models of contour integration. Vision Res. 45, 2511–2522 (2005).

    Article  Google Scholar 

  11. Intriligator, J. & Cavanagh, P. The spatial resolution of visual attention. Cognit. Psychol. 43, 171–216 (2001).

    Article  CAS  Google Scholar 

  12. Biederman, I. Recognition-by-components: a theory of human image understanding. Psychol. Rev. 94, 115–147 (1987).

    Article  Google Scholar 

  13. Tanaka, J.W. & Farah, M.J. Parts and wholes in face recognition. Q. J. Exp. Psychol. A 46, 225–245 (1993).

    Article  CAS  Google Scholar 

  14. Martelli, M., Majaj, N.J. & Pelli, D.G. Are faces processed like words? A diagnostic test for recognition by parts. J. Vis. 5, 58–70 (2005).

    Article  Google Scholar 

  15. Geisler, W. & Murray, R. Cognitive neuroscience: practice doesn't make perfect. Nature 423, 696–697 (2003).

    Article  CAS  Google Scholar 

  16. Levi, D.M. Crowding - an essential bottleneck for object recognition: a mini-review. Vision Res. 48, 635–354 (2008).

    Article  Google Scholar 

  17. Pelli, D.G., Palomares, M. & Majaj, N.J. Crowding is unlike ordinary masking: distinguishing feature integration from detection. J. Vis. 4, 1136–1169 (2004).

    PubMed  Google Scholar 

  18. He, S., Cavanagh, P. & Intriligator, J. Attentional resolution and the locus of visual awareness. Nature 383, 334–337 (1996).

    Article  CAS  Google Scholar 

  19. Blake, R., Tadin, D., Sobel, K.V., Raissian, T.A. & Chong, S.C. Strength of early visual adaptation depends on visual awareness. Proc. Natl. Acad. Sci. USA 103, 4783–4788 (2006).

    Article  CAS  Google Scholar 

  20. Bouma, H. Interaction effects in parafoveal letter recognition. Nature 226, 177–178 (1970).

    Article  CAS  Google Scholar 

  21. Freeman, J. & Pelli, D.G. An escape from crowding. J. Vis. 7, 1–14 (2007).

    Article  Google Scholar 

  22. Reddy, L. & VanRullen, R. Spacing affects some, but not all, visual searches: implications for theories of attention and crowding. J. Vis. 7, 1–17 (2007).

    Article  Google Scholar 

  23. Solomon, J.A. & Morgan, M.J. Stochastic re-calibration: contextual effects on perceived tilt. Proc Biol Sci 273, 2681–2686 (2006).

    Article  Google Scholar 

  24. Bouma, H. Visual interference in the parafoveal recognition of initial and final letters of words. Vision Res. 13, 767–782 (1973).

    Article  CAS  Google Scholar 

  25. Bex, P.J., Dakin, S.C. & Simmers, A.J. The shape and size of crowding for moving targets. Vision Res. 43, 2895–2904 (2003).

    Article  Google Scholar 

  26. van den Berg, R., Roerdink, J.B.T.M. & Cornelissen, F.W. On the generality of crowding: visual crowding in size, saturation and hue compared to orientation. J. Vis. 7, 1–11 (2007).

    Article  Google Scholar 

  27. Chung, S.T.L., Li, R.W. & Levi, D.M. Crowding between first- and second-order letter stimuli in normal foveal and peripheral vision. J. Vis. 7, 1–13 (2007).

    Article  Google Scholar 

  28. Pelli, D.G. et al. Crowding and eccentricity determine reading rate. J. Vis. 7, 1–36 (2007).

    Article  Google Scholar 

  29. Huey, E.B. The Psychology and Pedagogy of Reading (Macmillan, New York, 1908).

    Google Scholar 

  30. Legge, G.E., Pelli, D.G., Rubin, G.S. & Schleske, M.M. Psychophysics of reading. I. Normal vision. Vision Res. 25, 239–252 (1985).

    Article  CAS  Google Scholar 

  31. Levi, D.M., Song, S. & Pelli, D.G. Amblyopic reading is crowded. J. Vis. 7, 1–17 (2007).

    Article  Google Scholar 

  32. Vlaskamp, B.N., Over, E.A. & Hooge, I.T. Saccadic search performance: the effect of element spacing. Exp. Brain Res. 167, 246–259 (2005).

    Article  Google Scholar 

  33. Woodworth, R.S. Experimental Psychology (Holt, New York, 1938).

    Google Scholar 

  34. Bouma, H. Visual search and reading: eye movements and functional visual field: a tutorial review. in Attention and Performance VII (Requin, J.) (Erlbaum, Hillsdale, New Jersey, 1978).

    Google Scholar 

  35. Bosse, M.L., Tainturier, M.J. & Valdois, S. Developmental dyslexia: the visual attention span deficit hypothesis. Cognition 104, 198–230 (2007).

    Article  Google Scholar 

  36. McConkie, G.W. & Rayner, K. The span of the effective stimulus during a fixation in reading. Percept. Psychophys. 17, 578–586 (1975).

    Article  Google Scholar 

  37. Engbert, R., Nuthmann, A., Richter, E.M. & Kliegl, R. SWIFT: a dynamical model of saccade generation during reading. Psychol. Rev. 112, 777–813 (2005).

    Article  Google Scholar 

  38. O'Regan, J.K. Eye movements and reading. Rev. Oculomot. Res. 4, 395–453 (1990).

    CAS  PubMed  Google Scholar 

  39. Legge, G.E. Psychophysics of Reading in Normal and Low Vision (Erlbaum, Mahwah, New Jersey, 2007).

    Google Scholar 

  40. Motter, B.C. & Simoni, D.A. The roles of cortical image separation and size in active visual search performance. J. Vis. 7, 1–15 (2007).

    Article  Google Scholar 

  41. Stanovich, K.E., Siegel, L.S. & Gottardo, A. Converging evidence for phonological and surface subtypes of reading disability. J. Educ. Psychol. 89, 114–127 (1997).

    Article  Google Scholar 

  42. Bouma, H. & Legein, C.P. Foveal and parafoveal recognition of letters and words by dyslexics and by average readers. Neuropsychologia 15, 69–80 (1977).

    Article  CAS  Google Scholar 

  43. Prado, C., Dubois, M. & Valdois, S. The eye movements of dyslexic children during reading and visual search: impact of the visual attention span. Vision Res. 47, 2521–2530 (2007).

    Article  Google Scholar 

  44. Kwon, M., Legge, G.E. & Dubbels, B.R. Developmental changes in the visual span for reading. Vision Res. 47, 2889–2900 (2007).

    Article  Google Scholar 

  45. Lévy-Schoen, A. Exploration et connaissance de l'espace visuel sans vision périphérique. Trav. Hum. 39, 63–72 (1976).

    Google Scholar 

  46. Chung, S.T.L., Levi, D.M. & Legge, G.E. Spatial-frequency and contrast properties of crowding. Vision Res. 41, 1833–1850 (2001).

    Article  CAS  Google Scholar 

  47. Toet, A. & Levi, D.M. The two-dimensional shape of spatial interaction zones in the parafovea. Vision Res. 32, 1349–1357 (1992).

    Article  CAS  Google Scholar 

  48. Taylor, S.E. Eye movements in reading: facts and fallacies. Am. Ed. Res. J. 2, 187–202 (1965).

    Article  Google Scholar 

  49. Valdois, S. et al. Phonological and visual processing deficits can dissociate in developmental dyslexia: evidence from two case studies. Read. Writing 16, 541–572 (2003).

    Article  Google Scholar 

  50. Martelli, M., Di Filippo, G., Spinelli, D. & Zoccolotti, P. Crowding, reading and developmental dyslexia. Perception 35, supp 174 (2006).

    Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Psychology and Center for Neural Science, New York University, 6 Washington Place, New York, 10003, New York, USA

    Denis G Pelli & Katharine A Tillman

Authors
  1. Denis G Pelli
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Katharine A Tillman
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Denis G Pelli.

Supplementary information

Supplementary Text and Figures

Supplementary Figures 1–5, Supplementary Discussion and Supplementary Note (PDF 435 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Pelli, D., Tillman, K. The uncrowded window of object recognition. Nat Neurosci 11, 1129–1135 (2008). https://doi.org/10.1038/nn.2187

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nn.2187

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing