David L. Wilson

Neuroscience and Conscious Will

A review of Who’s in Charge? Free Will and the Science of the Brain. The Gifford Lectures 2009. By Michael S. Gazzaniga. Ecco. New York: HarperCollins Publishers.

Neurobiology of Human Action: Is Downward Causation Necessary?

27.99. ix 260 p.; ill.; index. ISBN: 978-0-06-190610-7. 2011. Gazzaniga has written a book about decisionmaking in the brain and much more—from emergent processes to our legal system. The volume is based on his 2009 Gifford lectures. The book is chock full of interesting studies in neuroscience that give us insights into who we are. He uses these studies as a backdrop for exploring big questions about free will, the relationship between mind and brain, and the role that social interactions play in creating who we are. Many fascinating experimental results are described, from how the brain is organized to innate social predilections, and he has a good set of references for anyone who wants to know more. Gazzaniga has a wide grasp of recent findings in cognitive neuroscience, a field that he helped to create. As his central challenge, the author attempts to unravel the puzzle of how we can have a feeling of being in charge (“free will”) when our brains appear to be physically determined machines. He begins by providing readers with a history of neuroscience views on topics ranging from the roles of nature and nurture in shaping behavior to the nature of brain organization. He presents in some detail the evidence for localization of brain functions to particular parts of the brain. Given the evidence from 19th-century neurologists who identified the specific effects of localized brain damage, it is interesting that the equipotent view of brain function by researchers such as Lashley held any sway in the 20th century. Gazzaniga participated in some of the studies confirming the neurologists’ views when he worked on split-brain patients. We now accept that the brain contains many localized, dynamically interacting systems, both conscious and nonconscious. Gazzaniga identifies one of these as an interpreter module located on the left side of the brain, and suggests that it creates after-the-fact explanations for actions that happen too quickly to be conscious. He suggests that the left-brain interpreter gains input from different parts of the brain and always is trying to weave things into a story. He appears to assume that this is the role of consciousness in most, or all, of our decisions—an after-the-fact role, but there is little evidence to support such an extension from the short response-time experiments that he describes. He does acknowledge the possibility that conscious actions could be involved, in real time, in blocking some fast actions. What is not as clear is whether such an interpreter module, or other conscious brain processes, could influence behavior over the longer term. To some extent, it is evident that the interpreter module can influence behavior, since it can control speech as it describes to others the stories it weaves together! Even given his view of the interpreter module as acting after the fact, the author attempts