Split-Brain: What We Know Now and Why This is Important for Understanding Consciousness
Edward H.F. de Haan, Paul M. Corballis, Steven A. Hillyard, Carlo A. Marzi, Anil K. Seth, Victor A. F. Lamme, Lukas J. Volz, Mara Fabri, Elizabeth Schechter, Tim Bayne, Michael C. Corballis, Yair Pinto
Neuropsychology Review May 12, 2020 DOI: 10.1007/s11065-020-09439-3 (opens in new tab)
Study at a glance
AI-extracted from the abstract| Characteristics | Collective review Peer reviewed |
|---|---|
| Keywords | Consciousness Miller Corpus callosum Psychogenic disease Perspective graphical Cognitive psychology Neuropsychology Action physics Cognitive science Epistemology Psychoanalysis Cognition |
| Citations | 86 |
| Key findings | Callosotomy broadly disrupts functional integration but leaves some processes unified; evidence is insufficient to determine whether consciousness is split or unified. |
Abstract
Recently, the discussion regarding the consequences of cutting the corpus callosum ("split-brain") has regained momentum (Corballis, Corballis, Berlucchi, & Marzi, Brain, 141(6), e46, 2018; Pinto et al., Brain, 140(5), 1231-1237, 2017a; Pinto, Lamme, & de Haan, Brain, 140(11), e68, 2017; Volz & Gazzaniga, Brain, 140(7), 2051-2060, 2017; Volz, Hillyard, Miller, & Gazzaniga, Brain, 141(3), e15, 2018). This collective review paper aims to summarize the empirical common ground, to delineate the different interpretations, and to identify the remaining questions. In short, callosotomy leads to a broad breakdown of functional integration ranging from perception to attention. However, the breakdown is not absolute as several processes, such as action control, seem to remain unified. Disagreement exists about the responsible mechanisms for this remaining unity. The main issue concerns the first-person perspective of a split-brain patient. Does a split-brain harbor a split consciousness or is consciousness unified? The current consensus is that the body of evidence is insufficient to answer this question, and different suggestions are made with respect to how future studies might address this paucity. In addition, it is suggested that the answers might not be a simple yes or no but that intermediate conceptualizations need to be considered.