The case study of John has provided a unique insight into the nature of visual agnosia and more broadly into the underlying processes which support human vision. After suffering a stroke, John had problems in recognizing common objects, faces, seeing colours, reading and finding his way around his environment. A Reader in Visual Agnosia brings together the primary scientific papers describing the detailed investigations for each visual problem which the authors carried out with John, known as patient HJA. This work was summarised initially in To See But Not To See (1987), and 26 years later in A Case Study in Visual Agnosia Revisited (2013).
The chapters are divided into 6 parts corresponding to the key areas of investigation:
Each part contains a short introduction, written by the two leading researchers who worked with John, which highlights the relations between the papers and demonstrates the pathway of the case analysis. The book will be invaluable to students and researchers in visual cognition, cognitive neuropsychology and vision neuroscience.
Part 1: Integrative visual agnosia 1. A case of integrative visual agnosia. (1987), Riddoch, M.J. & Humphreys, G.W. 2. The computation of occluded contours in visual agnosia: Evidence for early computation prior to shape binding and figure-ground coding. (2000), Giersch, A., Humphreys, G.W., Boucart, M. & Kovacs, I. 3. A two-stage account of computing and binding occluded and visible contours: Evidence from visual agnosia and effects of lorazepam. (2006), Giersch, A., Humphreys, G.W., Barthaud, J.C. & Landmanbn, C. 4. The necessary role of the dorsal visual route in the heterarchical coding of global visual pattern: Evidence from neuropsychological fMRI. (2014), Lestou, V., Kourtzi, Z., Humphreys, K.L., Lam, J. & Humphreys, G.W. 5. Parallel pattern processing in visual agnosia. (1992), Humphreys, G.W., Riddoch, M.J., Quinlan, P.T., Price, C.J. & Donnelly, N. Part 2: Seeing the whole 6. The computation of perceptual structure from collinearity and closure: Normality and pathology. (1992), Boucart, M. & Humphreys, G.W. 7. Ventral extra-striate cortical areas are required for optimal orientation averaging. (2007), Allen, H.A., Humphreys, G.W. & Bridge, H. 8. Interactive processes in perceptual organization: Evidence from visual agnosia. (1985), Humphreys, G.W., Riddoch, M.J. & Quinlan, P.T. 9. A tale of two agnosias: Distinctions between form and integrative agnosia. (2008), Riddoch, M.J., Humphreys, G.W., Akthar, N., Bracewell, R.M & Schofield, A.J. 10. The effects of view in depth on the identification of line drawings and silhouettes of familiar objects: Normality and pathology. (1999), Lawson, R. & Humphreys, G.W. 11. The real object advantage in agnosia: Evidence of a role for shading and depth in object recognition. (2001), Chainay, H. & Humphreys, G.W.Part 3: What’s in a face?12. Expression is computed separately from facial identity, and it is computed separately for moving and static faces: Neuropsychological evidence. (1993), Humphreys, G.W., Donnelly, N. & Riddoch, M.J. 13. Exploring the role of motion in prosopagnosia: Recognizing, learning and matching faces. (2004),Lander, K., Humphreys, G.W. & Bruce, V. 14. Recognition impairments and face imagery. (1994), Young, A.W., Humphreys, G.W., Riddoch, M.J., Hellalwell, D.J. & de Haan, E.H.F. Part 4: Colour, movement, action!15. Human colour discrimination based on a non-parvocellular pathway. (1996), Troscianko, T., Davidoff, J., Humphreys, G.W., Landis, T., Fahle, M., Greenlee, M., Brugger, P. & Phillips, W. 16. The neural representation of objects in space: A dual coding account. (1998), Humphreys, G.W. 17. Visual and spatial short-term memory in visual agnosia. (2003), Riddoch, M.J., Humphreys, G.W., Hardy, E., Blott, W. & Smith, A. Part 5: The written word 18. The ‘special effect’ of case mixing on word identification: Neuropsychological and TMS studies dissociating case mixing from contrast reduction. (2006), Braet, W. & Humphreys, G.W.Part 6: Living with agnosia 19. Memories are made of this: The effects of time on stored visual knowledge in a case of visual agnosia. (1999), Riddoch, M.J., Humphreys, G.W., Gannon, T., Blott, W. & Jones, V.