Skip to main content
PMC home page
Philosophical Transactions of the Royal Society B: Biological Sciences logoLink to Philosophical Transactions of the Royal Society B: Biological Sciences
. 1997 Aug 29;352(1358):1249–1256. doi: 10.1098/rstb.1997.0107

Vision without knowledge.

A D Milner 1
PMCID: PMC1692005  PMID: 9304691

Abstract

A brain-damaged patient (D.F.) with visual form agnosia is described and discussed. D.F. has a profound inability to recognize objects, places and people, in large part because of her inability to make perceptual discriminations of size, shape or orientation, despite having good visual acuity. Yet she is able to perform skilled actions that depend on that very same size, shape and orientation information that is missing from her perceptual awareness. It is suggested that her intact vision can best be understood within the framework of a dual processing model, according to which there are two cortical processing streams operating on different coding principles, for perception and for action, respectively. These may be expected to have different degrees of dependence on top-down information. One possibility is that D.F.'s lack of explicit awareness of the visual cues that guide her behaviour may result from her having to rely on a processing system which is not knowledge-based in a broad sense. Conversely, it may be that the perceptual system can provide conscious awareness of its products in normal individuals by virtue of the fact that it does interact with a stored base of visual knowledge.

Full Text

The Full Text of this article is available as a PDF (166.4 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Aglioti S., DeSouza J. F., Goodale M. A. Size-contrast illusions deceive the eye but not the hand. Curr Biol. 1995 Jun 1;5(6):679–685. doi: 10.1016/s0960-9822(95)00133-3. [DOI] [PubMed] [Google Scholar]
  2. Baizer J. S., Ungerleider L. G., Desimone R. Organization of visual inputs to the inferior temporal and posterior parietal cortex in macaques. J Neurosci. 1991 Jan;11(1):168–190. doi: 10.1523/JNEUROSCI.11-01-00168.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Brenner E., Smeets J. B. Size illusion influences how we lift but not how we grasp an object. Exp Brain Res. 1996 Oct;111(3):473–476. doi: 10.1007/BF00228737. [DOI] [PubMed] [Google Scholar]
  4. Bridgeman B., Lewis S., Heit G., Nagle M. Relation between cognitive and motor-oriented systems of visual position perception. J Exp Psychol Hum Percept Perform. 1979 Nov;5(4):692–700. doi: 10.1037//0096-1523.5.4.692. [DOI] [PubMed] [Google Scholar]
  5. Bridgemen B., Kirch M., Sperling A. Segregation of cognitive and motor aspects of visual function using induced motion. Percept Psychophys. 1981 Apr;29(4):336–342. doi: 10.3758/bf03207342. [DOI] [PubMed] [Google Scholar]
  6. Carey D. P., Harvey M., Milner A. D. Visuomotor sensitivity for shape and orientation in a patient with visual form agnosia. Neuropsychologia. 1996 May;34(5):329–337. doi: 10.1016/0028-3932(95)00169-7. [DOI] [PubMed] [Google Scholar]
  7. Castiello U., Jeannerod M. Measuring time to awareness. Neuroreport. 1991 Dec;2(12):797–800. doi: 10.1097/00001756-199112000-00017. [DOI] [PubMed] [Google Scholar]
  8. Dijkerman H. C., Milner A. D., Carey D. P. The perception and prehension of objects oriented in the depth plane. I. Effects of visual form agnosia. Exp Brain Res. 1996 Dec;112(3):442–451. doi: 10.1007/BF00227950. [DOI] [PubMed] [Google Scholar]
  9. Dijkerman H. C., Milner A. D. Copying without perceiving: motor imagery in visual form agnosia. Neuroreport. 1997 Feb 10;8(3):729–732. doi: 10.1097/00001756-199702100-00030. [DOI] [PubMed] [Google Scholar]
  10. Faillenot I., Toni I., Decety J., Grégoire M. C., Jeannerod M. Visual pathways for object-oriented action and object recognition: functional anatomy with PET. Cereb Cortex. 1997 Jan-Feb;7(1):77–85. doi: 10.1093/cercor/7.1.77. [DOI] [PubMed] [Google Scholar]
  11. Gentilucci M., Chieffi S., Deprati E., Saetti M. C., Toni I. Visual illusion and action. Neuropsychologia. 1996 May;34(5):369–376. doi: 10.1016/0028-3932(95)00128-x. [DOI] [PubMed] [Google Scholar]
  12. Goodale M. A., Jakobson L. S., Keillor J. M. Differences in the visual control of pantomimed and natural grasping movements. Neuropsychologia. 1994 Oct;32(10):1159–1178. doi: 10.1016/0028-3932(94)90100-7. [DOI] [PubMed] [Google Scholar]
  13. Goodale M. A., Meenan J. P., Bülthoff H. H., Nicolle D. A., Murphy K. J., Racicot C. I. Separate neural pathways for the visual analysis of object shape in perception and prehension. Curr Biol. 1994 Jul 1;4(7):604–610. doi: 10.1016/s0960-9822(00)00132-9. [DOI] [PubMed] [Google Scholar]
  14. Goodale M. A., Milner A. D., Jakobson L. S., Carey D. P. A neurological dissociation between perceiving objects and grasping them. Nature. 1991 Jan 10;349(6305):154–156. doi: 10.1038/349154a0. [DOI] [PubMed] [Google Scholar]
  15. Goodale M. A., Pelisson D., Prablanc C. Large adjustments in visually guided reaching do not depend on vision of the hand or perception of target displacement. Nature. 1986 Apr 24;320(6064):748–750. doi: 10.1038/320748a0. [DOI] [PubMed] [Google Scholar]
  16. Grafton S. T., Arbib M. A., Fadiga L., Rizzolatti G. Localization of grasp representations in humans by positron emission tomography. 2. Observation compared with imagination. Exp Brain Res. 1996 Nov;112(1):103–111. doi: 10.1007/BF00227183. [DOI] [PubMed] [Google Scholar]
  17. Grafton S. T., Fagg A. H., Woods R. P., Arbib M. A. Functional anatomy of pointing and grasping in humans. Cereb Cortex. 1996 Mar-Apr;6(2):226–237. doi: 10.1093/cercor/6.2.226. [DOI] [PubMed] [Google Scholar]
  18. Gregory R. L. Perceptions as hypotheses. Philos Trans R Soc Lond B Biol Sci. 1980 Jul 8;290(1038):181–197. doi: 10.1098/rstb.1980.0090. [DOI] [PubMed] [Google Scholar]
  19. Humphrey G. K., Symons L. A., Herbert A. M., Goodale M. A. A neurological dissociation between shape from shading and shape from edges. Behav Brain Res. 1996 Apr;76(1-2):117–125. doi: 10.1016/0166-4328(95)00190-5. [DOI] [PubMed] [Google Scholar]
  20. Jakobson L. S., Archibald Y. M., Carey D. P., Goodale M. A. A kinematic analysis of reaching and grasping movements in a patient recovering from optic ataxia. Neuropsychologia. 1991;29(8):803–809. doi: 10.1016/0028-3932(91)90073-h. [DOI] [PubMed] [Google Scholar]
  21. Jakobson L. S., Goodale M. A. Factors affecting higher-order movement planning: a kinematic analysis of human prehension. Exp Brain Res. 1991;86(1):199–208. doi: 10.1007/BF00231054. [DOI] [PubMed] [Google Scholar]
  22. Jeannerod M., Decety J., Michel F. Impairment of grasping movements following a bilateral posterior parietal lesion. Neuropsychologia. 1994 Apr;32(4):369–380. doi: 10.1016/0028-3932(94)90084-1. [DOI] [PubMed] [Google Scholar]
  23. Jeannerod M. The formation of finger grip during prehension. A cortically mediated visuomotor pattern. Behav Brain Res. 1986 Feb;19(2):99–116. doi: 10.1016/0166-4328(86)90008-2. [DOI] [PubMed] [Google Scholar]
  24. Landis T., Graves R., Benson D. F., Hebben N. Visual recognition through kinaesthetic mediation. Psychol Med. 1982 Aug;12(3):515–531. doi: 10.1017/s0033291700055616. [DOI] [PubMed] [Google Scholar]
  25. Matsumura M., Kawashima R., Naito E., Satoh K., Takahashi T., Yanagisawa T., Fukuda H. Changes in rCBF during grasping in humans examined by PET. Neuroreport. 1996 Feb 29;7(3):749–752. doi: 10.1097/00001756-199602290-00017. [DOI] [PubMed] [Google Scholar]
  26. Milner A. D. Cerebral correlates of visual awareness. Neuropsychologia. 1995 Sep;33(9):1117–1130. doi: 10.1016/0028-3932(95)00052-5. [DOI] [PubMed] [Google Scholar]
  27. Milner A. D., Goodale M. A. Visual pathways to perception and action. Prog Brain Res. 1993;95:317–337. doi: 10.1016/s0079-6123(08)60379-9. [DOI] [PubMed] [Google Scholar]
  28. Milner A. D., Heywood C. A. A disorder of lightness discrimination in a case of visual form agnosia. Cortex. 1989 Sep;25(3):489–494. doi: 10.1016/s0010-9452(89)80062-0. [DOI] [PubMed] [Google Scholar]
  29. Milner A. D., Perrett D. I., Johnston R. S., Benson P. J., Jordan T. R., Heeley D. W., Bettucci D., Mortara F., Mutani R., Terazzi E. Perception and action in 'visual form agnosia'. Brain. 1991 Feb;114(Pt 1B):405–428. doi: 10.1093/brain/114.1.405. [DOI] [PubMed] [Google Scholar]
  30. Morel A., Bullier J. Anatomical segregation of two cortical visual pathways in the macaque monkey. Vis Neurosci. 1990 Jun;4(6):555–578. doi: 10.1017/s0952523800005769. [DOI] [PubMed] [Google Scholar]
  31. Perenin M. T., Vighetto A. Optic ataxia: a specific disruption in visuomotor mechanisms. I. Different aspects of the deficit in reaching for objects. Brain. 1988 Jun;111(Pt 3):643–674. doi: 10.1093/brain/111.3.643. [DOI] [PubMed] [Google Scholar]
  32. Sparr S. A., Jay M., Drislane F. W., Venna N. A historic case of visual agnosia revisited after 40 years. Brain. 1991 Apr;114(Pt 2):789–800. doi: 10.1093/brain/114.2.789. [DOI] [PubMed] [Google Scholar]
  33. Webster M. J., Bachevalier J., Ungerleider L. G. Connections of inferior temporal areas TEO and TE with parietal and frontal cortex in macaque monkeys. Cereb Cortex. 1994 Sep-Oct;4(5):470–483. doi: 10.1093/cercor/4.5.470. [DOI] [PubMed] [Google Scholar]
  34. Wong E., Mack A. Saccadic programming and perceived location. Acta Psychol (Amst) 1981 Aug;48(1-3):123–131. doi: 10.1016/0001-6918(81)90054-8. [DOI] [PubMed] [Google Scholar]
  35. Young M. P. Objective analysis of the topological organization of the primate cortical visual system. Nature. 1992 Jul 9;358(6382):152–155. doi: 10.1038/358152a0. [DOI] [PubMed] [Google Scholar]

Articles from Philosophical Transactions of the Royal Society B: Biological Sciences are provided here courtesy of The Royal Society

RESOURCES