title: Split brain: divided perception but undivided consciousness.
abstract: In extensive studies with two split-brain patients we replicate the standard finding that stimuli cannot be compared across visual half-fields, indicating that each hemisphere processes information independently of the other. Yet, crucially, we show that the canonical textbook findings that a split-brain patient can only respond to stimuli in the left visual half-field with the left hand, and to stimuli in the right visual half-field with the right hand and verbally, are not universally true. Across a wide variety of tasks, split-brain patients with a complete and radiologically confirmed transection of the corpus callosum showed full awareness of presence, and well above chance-level recognition of location, orientation and identity of stimuli throughout the entire visual field, irrespective of response type (left hand, right hand, or verbally). Crucially, we used confidence ratings to assess conscious awareness. This revealed that also on high confidence trials, indicative of conscious perception, response type did not affect performance. These findings suggest that severing the cortical connections between hemispheres splits visual perception, but does not create two independent conscious perceivers within one brain.
authors.affiliation: Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC) Center, University of Amsterdam, The Netherlands.
authors.forename: Yair
authors.initials: Y
authors.lastname: Pinto
authors.affiliation: Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands.
authors.forename: David A
authors.initials: DA
authors.lastname: Neville
authors.affiliation: Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC) Center, University of Amsterdam, The Netherlands.
authors.forename: Marte
authors.initials: M
authors.lastname: Otten
authors.affiliation: School of Psychology, University of Auckland, Auckland, New Zealand.
authors.forename: Paul M
authors.initials: PM
authors.lastname: Corballis
authors.affiliation: Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC) Center, University of Amsterdam, The Netherlands.
authors.forename: Victor A F
authors.initials: VAF
authors.lastname: Lamme
authors.affiliation: Department of Psychology, University of Amsterdam, Amsterdam, The Netherlands.|Amsterdam Brain and Cognition (ABC) Center, University of Amsterdam, The Netherlands.
authors.forename: Edward H F
authors.initials: EHF
authors.lastname: de Haan
authors.affiliation: Epilepsy Center-Neurological Clinic, Azienda 'Ospedali Riuniti', Ancona, Italy.
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Foschi
authors.affiliation: Department of Experimental and Clinical Medicine, Marche Politechnical University, Ancona, Italy.
authors.forename: Mara
authors.initials: M
authors.lastname: Fabri
mesh_terms: D001921:Brain / Q000502:physiology; D003243:Consciousness / Q000502:physiology*; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D050812:Split-Brain Procedure / Q000009:adverse effects*; D058609:Visual Field Tests; D014794:Visual Fields / Q000502:physiology*; D014796:Visual Perception / Q000502:physiology*
keywords: consciousness; epilepsy; neurosurgery; split-brain; visual fields