Michael Gazzaniga: Split brains and other heady tales (highlight from the archives)Michael Gazzaniga: Split brains and other heady tales (highlight from the archives)
All In The Mind
Beyond the hype of left brain versus right brain lies the work of acclaimed neuroscientist Michael Gazzaniga. His career was forged in the lab of Nobel laureate Roger Sperry, and together their trailblazing experiments have illuminated the differences between the brain's two hemispheres. Today he's on the US President's Bioethics Council, heads up a major project on neuroscience and the law, and is a prolific writer of popular neuroscience.
30:06•14 Nov 2009
Split Brains, Free Will and Who’s Really in Charge?
Episode Overview
- Split-brain surgery showed that two independent conscious systems can exist within one brain, each with different abilities.
- The left hemisphere acts as an interpreter, constantly inventing explanations for behaviour, even when it lacks the real cause.
- Popular ideas about a highly creative “right brain” and a logical “left brain” are an oversimplification of much more complex differences.
- Neuroscience is still too young to be a reliable guide in most court cases, and brain scans can easily be over-interpreted.
- Much crime in the United States is drug-related, raising deep concerns about addiction, inequality and the use of prisons as de facto psychiatric institutions.
“We’re all dualists. We immediately convert the biological reality of ourselves to personhood, to the fact that we’re talking to people, not brains.”
Gazzaniga talks about early work with split-brain patients like W.J., where a simple flash of an image to one side of the visual field showed that “two conscious systems can be created with the slice of a knife.” One hand knew what the picture was; the speaking half of the brain insisted it “didn’t see anything.” From there, the conversation heads into how the two hemispheres differ, why the left side acts as an “interpreter” constantly stitching together a story about our lives, and how that story is sometimes flat-out wrong.
Curious about how others manage both the mysteries of the brain and big questions about responsibility and choice? This archived highlight from *All In The Mind* brings neuroscientist Michael Gazzaniga together with host Natasha Mitchell for a lively tour through split-brain science, free will and the justice system. Rather than pop-psych quizzes about being "left-brained" or "right-brained", you’ll hear the research that actually started that whole craze.
There’s even a slightly humbling comparison with rats, whose simpler strategy in a betting game actually beats human overthinking. For anyone interested in addiction or compulsive behaviour, the later section on neuroscience and the law hits close to home. Gazzaniga talks about brain lesions, psychopathy, and why prison populations in the United States are so high, noting that much crime is drug-related and that 80% of prisoners are people of colour.
He questions how far brain scans and diagnoses should go in excusing behaviour, while still recognising rare cases where mental illness matters for legal responsibility. You’ll come away questioning ideas about being “wired this way”, what responsibility really means, and how much of your story is your brain filling in the gaps. If the brain can trick you, what else might be shaping the choices you think you freely make?
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