Author: Michael S. Gazzaniga
APA Style Citation
Gazzaniga, M.S. (2011). Who`s In Charge: Free Will and the Science of the Brain, Harper Collins, New York, New York.
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The origin of this book is derived from the Gifford lecture series named after Scottish advocate and judge Adam Lord Gifford. These academic lectures have covered a wide variety of topics over the years from acclaimed academics in all areas, including famed psychologist William James. This book is the result of Gazzaniga's own Gifford Lecture.
Gazzaniga opens with an explanation of the unbelievable capacity of the human brain to adapt, process information, and to adjust to trauma or external factors. Gazzaniga discusses the similarities and differences in the brain of human and the brains of other animals. While humans share many similarities with the brains of other animals, the extremely large cerebral cortex (82 percent of the human brain) and forebrain allows for incredibly complex thought and higher-order thinking that significantly exceeds that of all other species.
Gazzaniga then lays out the difference in how psychologists historically believed humans gained information. Those like John Watson believed humans were born a blank slate and experience shaped the individual one was to become through the person`s experience with rewards, punishments and observations. Others believed that genes alone determined one`s intelligence, personality, and other characteristics. Eventually, researchers began the study of individual neurons and brain areas, many of which demonstrated localization of brain function and a more interactionist approach was born.
Gazzaniga provides an example regarding how these interactions help us evaluate stimuli in our environment such as how one determines the brightness of an object. Brightness is in part determined by the amount of light that enters the eye which can in large part be explained by biological factors. However, our experience in the world helps identify a particular color, as well as the other surrounding colors, interact to create our experience of color in the world. Beau Lotto discusses how easily we can be fooled by manipulating environmental factors (see resources for Beau Lotto TED talk). This current interactionist view of how the brain functions is that the large-scale plan is genetic, but the specific connections and functions are a result of both epigenetic functions and experience. Genetics can set boundaries, for example, the process of neurogenesis is highly controlled by DNA and gradually decreases as one ages. Asymmetries such as the localization of language in the left hemisphere and specifically in the language productions area of the left frontal lobe where Broca`s area is located are determined primarily by genetics. However, young children with damage to the left frontal lobe or with hemispherectomies can “rewire” their brain so that language is redirected to the right hemisphere.
Some of our behaviors may not be unique to the genes passed along directly from our parents, but rather from multiple generations as humans have adapted to changing environments. Gazzaniga suggests humans and animals may be born ready to fear animals such as tigers and snakes with front facing eyes and sharp teeth. Even squirrels who are raised in isolation and have never seen a snake before, avoid them when they are presented. Other fears may be learned through negative life experiences, and others still may develop from an interaction between these two factors. These interactionist occurrences even span to moral dilemmas, for example, in the infamous trolley problem, one must decide if they should flip a switch to have the trolley kill one person on the track or leave the switch as is and kill five people working on the tracks. Most people (89%) will choose to flip the switch, but when the situation is changed slightly, and they are asked if they would push a person onto the tracks to save five people 89% of people say “no.” Gazzaniga believes that the altruistic helping behavior may be inborn, the social construct of making the moral dilemma personal or impersonal is likely to be influenced by learning what behaviors are acceptable and which are unacceptable as determining by what we have learned through our experiences. Similarly, we are born with a predisposition to learn language, but our surroundings will determine which language(s) we ultimately master.
Gazzaniga is perhaps most well-known for his research with split-brained patients, having taken the reigns in this area from Nobel prize-winning researcher Roger Sperry who split the brains of severely epileptic patients to save at least one hemisphere from the debilitating epileptic seizures. While some see this treatment as inhumane and unethical, Gazzaniga cites that these patients on average experience a 60-70 percent reduction in the number of seizures they are experiencing and others experienced no further seizures. The corpus callosum is not completely split; but is still connected at the brainstem allowing for basic life functions to reach both hemispheres. There is also some communication that remains between hemispheres because it has been shown that emotional stimuli presented to one hemisphere still impacts the judgment in the other hemisphere. While split-brained patients appear completely normal in most ways, Gazzaniga has designed a unique method to test the experiences of split-brained patients. By presenting a visual stimulus very briefly at the center of a screen, Gazzaniga can control images presented to the patients right or left visual field. Half of all visual information will be directed to the opposite hemisphere of the brain by way of the optic chiasm. The medial (inside) track crosses the optic chiasm to the opposite side of the brain while the lateral (outside) stays on the same side as the incoming message. Since the left hemisphere is superior at language and the right at spatial tasks, it is then possible in split-brained patients to isolate the hemisphere receiving each message. A spoon displayed to the right visual field will be verbally identified but cannot be selected properly from a ruler a pencil or a teacup. Conversely, if the object were displayed to the left visual field, it could be identified spatially but not verbally. These studies are not possible with “normal” individuals because the corpus callosum serves as a conduit between hemispheres.
When applying moral situations to split-brained patients, Gazzaniga poses questions first to a control group with intact brains and then to split-brained patients. When asked about a secretary who accidentally puts poison in her boss`s coffee while intending to put sugar in and another she wants to poison her boss but accidentally puts sugar in his coffee, those with intact brains say the intention is what determines if the action is right or wrong. Those with split-brains, however, indicate that the outcome is what matters, this is likely because likely because belief attribution is located in the right hemisphere of the brain and this cannot be easily integrated moral reasoning components of the brain,
Ultimately, the mind constrains the brain, and social processes constrain individual`s minds. These interactions between organisms and their environments are bidirectional. The organism can change the environment and vice versa. Complete dependency on localization of function in the brain would mean that we are completely beholden to a single malfunction while total reliance on the environment would create a lack of consistency with personality or socialization, this interaction is necessary, it is what makes us human.
Other Related Resources
Diane Rehm Show: Interview with Michael Gazzaniga discussing the book “Who`s in Charge?”
Michel Gazzaniga Website University of California Santa Barbara
The Information Philosopher: Interview with Michael Gazzaniga
Videos on Gazzaniga`s work with Split-brained patients
Beau Lotto: Ted talk on Sensory Perceptions
René Balligeron : Object Permanence
Morality in Chimps: TED talk with Frans de Waal
Law and Neuroscience: Vanderbilt University
Psychological Figures and Concepts
Anterior Cingulate Cortex
False Belief Test
Nature versus Nurture Debate
Sensitive Period (Critical Period)
Stream of Consciousness
Sympathetic Nervous System
Theory of Mind
Transcranial Magnetic Stimulation (TMS)
Ventromedial Prefrontal Cortex
Rene Ballageon (Video of preference of babies for puppets who divide things equally)
Franz Joseph Gall
Hermann von Helmholtz