School of Psychology - Leading psychological science, scholarship and practice
PhD (McGill), honorary LLD
FAPA, FAPS, FRSNZ, FAAAS
Phone: +64 9 923 8561
Room: HSB 537
My primary research interests are in cognitive neuroscience, including visual perception, visual imagery, attention and memory. My more specialised interests are in cerebral asymmetry of function and in how people recognise rotated shapes. I investigate these topics through the techniques of basic human experimental psychology, through brain imaging Electroencephalography (EEG) and Functional magnetic resonance imaging (fMRI), and through the study of individuals who have undergone section of the forebrain commissures.
My secondary interest is the evolution of language, and in particular the theory that language evolved from manual gestures.
Processing of rotated shapes
One of the problems of shape recognition is how people recognise shapes that have been rotated away from the upright. Our research suggests that people extract descriptions of shapes that are independent of their orientations, for example, when rotated shapes are presented in rapid sequence, people can usually name the shapes, but cannot tell their orientations. They appear also to be impervious to left-right sense of the shapes (eg, whether a letter such as R is normal or backward). Once identified, the orientation of the shape may then be determined, and only through a later process of mental rotation is its left-right sense established. We are investigating and refining our understanding of these processes both through experimental techniques and through the use of EEG and fMRI to determine which areas in the brain are involved.
Interhemispheric integration in the split brain
Individuals who have undergone section of the corpus callosum (usually for the relief of intractable epilepsy) generally show functional disconnection between the two sides of visual space. There are, however, some exceptions. Our research has shown some low-level visual interactions between the disconnected hemispheres and we are further exploring their nature through the study of several split-brained patients in Italy. This provides insight into the role of subcortical structures in vision.
Evolution of language
Arising from my interest in the connection between handedness and cerebral asymmetry for language, I have developed an old idea that language evolved from manual gestures rather than from animal calls. This idea is supported by studies of the role of manual gesture in normal speech, by investigations of signed languages developed by deaf communities, by attempts to reach language to nonhuman primates and by evidence that the homologues of the speech areas in nonhuman primates has to go with manual action rather than with vocalisation. My current endeavour is to provide a plausible account of how the transition might have occurred, based on the premise that speech itself is a gestural system rather than an acoustic one.
Cerebral asymmetry in twins
This project uses magnetic resonance imaging (MRI) to examine functional and structural asymmetries in twins. A particular focus of interest is on identical twins of opposite handedness (so-called “mirror twins”), who comprise some 22% of the population of identical twins. The question is whether they also show mirroring of various indices of cerebral asymmetry. This project is supported by a Marsden grant, and is also providing general information about the interrelations between handedness and both structural and functional asymmetries.
- Corballis, M. C. 2009. The evolution and genetics of cerebral asymmetry. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 364, 867-879. http://dx.doi.org/10.1098/rstb.2008.0232
- Lewald, J., Peters, S., Corballis, M. C., & Hausmann, M. (2009). Perception of stationary and moving sound following cortectomy. Neuropsychologia, 47, 962-971. http://dx.doi.org/10.1016/j.neuropsychologia.2008.10.016
- Milivojevic, B., Hamm, J. P., & Corballis, M. C. (2009). Functional neuroanatomy of mental rotation. Journal of Cognitive Neuroscience, 21, 945-959.http://www.mitpressjournals.org.ezproxy.auckland.ac.nz/doi/pdf/10.1162/jocn.2009.21085
- Corballis, M. C. (2009). The evolution of language. Annals of the New York Academy of Sciences, 1156, 19-43. http://dx.doi.org/10.1111/j.1749-6632.2009.04423.x
- Suddendorf, T., Addis, D. R., & Corballis, M. C. (2009). Mental time travel and the shaping of the human mind. Philosophical Transactions of the Royal Society of London B: Biological Sciences, 364, 1317-1324. http://dx.doi.org/10.1098/rstb.2008.0301
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