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My Brain Made Me Do It: The Rise of Neuroscience and the Threat to Moral Responsibility

My Brain Made Me Do It: The Rise of Neuroscience and the Threat to Moral Responsibility

by Eliezer J. Sternberg

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As scientists continue to explore how the brain works, using ever more sophisticated technology, it seems likely that new findings will radically alter the traditional understanding of human nature. One aspect of human nature that is already being questioned by recent developments in neuroscience is free will. Do our decisions arise from purely mechanistic


As scientists continue to explore how the brain works, using ever more sophisticated technology, it seems likely that new findings will radically alter the traditional understanding of human nature. One aspect of human nature that is already being questioned by recent developments in neuroscience is free will. Do our decisions arise from purely mechanistic processes? Is our feeling of self-control merely an illusion created by our brains? If so, what will become of free will and moral responsibility? These thorny questions and many more are examined with great clarity and insight in this engaging exploration of neuroscience’s potential impact on moral responsibility. The author delves into a host of fascinating topics, including:

-the parts of the brain that scientists believe are involved in the exercise of will
-what Parkinson’s, Tourette’s, and schizophrenia reveal about our ability to control our actions
-whether criminal behavior is determined by brain chemistry
-how self-reflective consciousness may have evolved from a largely deterministic brain

Using illustrative examples from philosophy, mythology, history, and criminology, and with thorough discussions of actual scientific experiments, the author explores the threat of neuroscience to moral responsibility as he attempts to answer the question: Are we truly in control of our actions?

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Prometheus Books
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my brain MADE ME DO IT

By Eliezer J. Sternberg

Prometheus Books

Copyright © 2010 Eliezer J. Sternberg
All right reserved.

ISBN: 978-1-61614-165-3

Chapter One


Just after midnight on February 17, 1991, Stephen Mobley walks into a Domino's Pizza in Oakwood, Georgia, holding a silver, semiautomatic pistol in his hand. Only the store manager, twenty-four-year-old John Collins, is inside. Mobley points the gun at Collins and orders him to open the cash register. Collins does as he is told. As Mobley stuffs his jacket with stacks of bills, the store manager retreats to the corner and sits, silently trembling.

Having emptied the cash register, Mobley pauses. He looks over at Collins, who is clutching his hair and on the verge of tears. He barks at the store manager to approach him, ordering him to get on his knees. Now sobbing, Collins obeys. Mobley walks behind his victim and places the weapon against the back of his sweat-soaked head. Collins pleads with him for mercy, begging him to take the money and go. Mobley pulls the trigger.

After being captured one month later, Mobley does not appear to regret the murder. "If that fat son-of-a-bitch had not started crying, I would never have shot him," he says. He tells one of his guards that he plans to apply for the night manager position at Domino's, since he knows there is an opening available. He points to another guard and claims that he is "beginning to look more and more like a Domino's Pizza boy everyday." He keeps an empty Domino's Pizza box with him in his cell.

The task of defending Stephen Mobley is a difficult one. What can one say in favor of a killer who expresses no remorse? Mobley's attorneys begin with the medical examination, giving him a full physical and psychological workup. Their findings are scanty: Mobley does not have any physical, psychological, psychiatric, or neurological diseases. He doesn't have bipolar disorder, or schizophrenia, or Alzheimer's. The medical results return with only one minor discovery: Mobley has a slight deficiency of the enzyme monoamine oxidase A, responsible for breaking down serotonin, dopamine, and several other key neurotransmitters in the brain. The defense counsel knows that this is nowhere near enough to argue that Mobley is insane. Nevertheless, the team of lawyers decides to make a bold move. They declare that communication between neurons in Mobley's brain, influenced by the relative concentrations of neurotransmitters, caused Mobley to murder his victim. Mobley's attorneys release a statement:

Stagnant MOMA [monoamine oxidase A] activity among affected males resulted in the excretion of abnormally high amounts of the neurotransmitters serotonin, norepinephrine, dopamine, and epinephrine, all of which are normally broken down in the body using MOMA.... When these neurotransmitters accumulate in abnormal amounts due to a defect on the MOMA gene, affected individuals will have trouble handling stressful situations, causing them to respond excessively and at times, violently.

Effectively, their position is that Mobley cannot be held fully responsible for his crime because that crime was determined by his brain. His brain made him do it.

In the end, however, the jury was not convinced. Mobley was found guilty and subsequently executed on March 1, 2005.

Looking back on this case, what stands out to me is not the jury's verdict or the judge's sentence, but the defense counsel's strategy. Monoamine oxidase A is an enzyme that operates in every human brain, one of many that regulate the level of neurotransmitters and other brain chemicals, which in turn regulate communication between neurons. The amount of any given neurotransmitter in the brain, such as serotonin, is in a constant state of flux. It changes based on the needs of cells, the strength and number of incoming stimuli from the environment, and the frequency with which certain synapses are activated. The concentrations of chemicals in the brain vary from moment to moment and from person to person.

Are we to believe that one concentration of an enzyme causes a man to commit murder, another level of another enzyme causes him to lie, and another level of yet another enzyme causes him to give to charity?

Mobley's attorneys defended their client by claiming that his crime was caused by the interactions between neurons in his brain, through the exchange of various chemicals such as monoamine oxidase A. They chose this strategy because they assumed, as most people do, that the way a person behaves results from how his brain operates. But how is the case any different for someone with a perfectly healthy brain? The neurons in that person's brain are still firing, presumably generating his behavior.

Take, for example, a perfectly healthy person who tells a lie. What actually causes her to lie? She might provide a detailed rationale about her needs to achieve certain goals or her fear of revealing certain truths, but a scientific investigation will tell a very different story.

Deep within her brain, within the gray and white flesh of the cerebral hemispheres, through the weaves of neurons and glial cells, in between the delicate, arching tendrils of neighboring axons and dendrites, calcium ions are moving in and out of cells, regulating the exchange of tiny packets of the signal molecules known as neurotransmitters. These minute transactions create a signal that travels from the axonal bud of one neuron, down the snaking dendritic fiber of the next, propagating across to the axonal stem that follows, on and on from axon to dendrite and from neuron to neuron until finally the muscles are stimulated and the person speaks.

This woman is not mentally ill, any more than Mobley was as he stood with his gun to the head of his victim, contemplating his next move. Should he shoot Collins or just walk out the door?

When presented with a choice, I, too, may contemplate my next move, as in whether to lie or whether to tell the truth. I may take some time to consciously reflect on which option is best, based on my needs and values, but, at precisely the same time that I am supposedly steeped in reflection, billions of tiny calculations that I am unaware of are occurring in my brain-also resolving what I should do.

But if both these systems are at work, where does the decision come from? Do I control my decisions or does my brain?

Many neuroscientists today are convinced that it is my brain. The scientist Francis Crick writes that "'you,' your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." Neuroscientist Joseph LeDoux simply says, "You are your synapses. They are who you are." Regarding our ability to freely control our actions, neurologist Mark Hallett asserts that "the more you scrutinize it, the more you realize you don't have it." As unnerving as these claims may be, the problem goes deeper still.

In claiming that his brain caused him to murder John Collins, Mobley's lawyers were, philosophically speaking, saying that Mobley was not morally responsible for killing because he was caused to do so by his brain. We can summarize their argument as follows:

1. Neurobiological interactions in Mobley's brain, facilitated by a deficiency in the enzyme monoamine oxidase A, determined that Mobley kill Collins.

2. Determined actions are not free.

3. One cannot be held morally responsible for actions that are not free.

4. Therefore, Mobley cannot be held morally responsible for killing Collins.

However, the jury did hold Mobley responsible. In the jurors' view, Mobley was faced with a moral choice. After robbing the pizza store, he could have left without firing a shot. If he was worried about being recognized or about Collins calling the police, he could have come in wearing a mask and tied the store manager to a table. However, the jury members decided, Mobley chose to kill. They felt justified in blaming him because we hold people legally responsible for their actions, since we assume that people freely choose to act as they do. We assume that every person is a moral agent with the ability to consciously reason through decisions and act according to what he or she believes is right.

But what if the defense counsel was right? What if the complex operations in Mobley's brain caused him to steal? That would mean that his decision was not free, but rather forced upon him by his biological makeup. If everyone's behavior were caused by neurobiological wiring, then no decision could be made freely. It wouldn't matter if you robbed a bank or shot the president, kicked your dog or came late to work-it would all be caused by processes over which you had no control.

If it is the brain that determines our decisions, then each person has at his or her disposal a powerful argument against moral responsibility:

1. Neurobiological interactions in my brain determined that I did X.

2. Determined actions are not free.

3. One cannot be held morally responsible for actions that are not free.

4. Therefore, I cannot be held morally responsible for doing X.

In short, moral responsibility does not exist.

Yet my deepest feelings tell me that every decision I make is mine. I am a moral agent with the power to control my decisions. I have free will. It is my conscious faculties that willfully deliberate, often painstakingly, looking at details and considering principles, until I resolve to act, with the understanding that my action will have consequences for which I may have to answer. These feelings are intimately familiar to me and are essential ingredients of my identity.

On the other hand, my knowledge of brain science tells me that within my skull there exists a biological system more intricate than any other. I know that throughout my conscious deliberation, this dynamic system is firing with activity. Billions of networked entities are exchanging and modifying information in ways that can be correlated with my thought and behavior. I know also that I have neither a complete knowledge of this system's operation nor the power to fully control it.

I believe that both my conscious experience and the principles of neurobiology are true, yet when it comes to the making of a conscious decision, they appear to be fundamentally in conflict-and this conflict may threaten our perception of morality and responsibility. One of the main challenges in discussing this dilemma is deciding how to pose the question clearly, and I think that philosopher John Searle has done it correctly. So using Searle's construction, let me put the problem as precisely as I can.

Suppose that at time A, Mobley (or any person we might choose) is faced with a moral choice: to commit murder or walk away. At this moment, assume Mobley is aware of the reasons for deciding one way or the other and is completely mentally competent. Ten seconds later, at time B, he pulls the trigger and kills his victim. Assume that nothing interferes with his mental decision-making process between times A and B. We are concerned only with Mobley's mind and the choice he makes. If the sum of the neurobiological interactions in Mobley's brain at time A is sufficient to determine that, at time B, he commits murder, then free will and moral responsibility do not exist. He cannot be blamed for his crime because it was determined by his neurobiological circuitry: his brain made him do it. On the other hand, if the sum of the interactions in his brain at time A is insufficient to determine his decision to commit murder ten seconds later, then it is possible, but not certain, that he had free will and was responsible for what he did.

Our belief in moral responsibility, derived from the assumption that we consciously wield control over our thoughts and actions, seems to form the underpinning of nearly every facet of human life. It shapes the way we treat people around us, the hiring and firing of employees, the academic system of grading, the concepts of crime and punishment, and the relationship between parent and child. It is the origin of pride and guilt, care and fellowship. We can scarcely imagine discarding this idea, one so vital to our understanding of people and society.

Yet, in the shadow of emerging developments in the neurosciences, that essential freedom, or what we think of as a freedom, has come under threat. Neuroscience threatens to demonstrate-some say it has already demonstrated-that our sense of conscious will, that feeling which we know most intimately, is an illusion created by our biological machinery, and that we have no more say in the construction of our future than does a rock in its motion down a hill.

If this claim proves true, affirming the contention of Mobley's lawyers that our choices are determined by the rules of neural processing, how are we to understand moral agency, our moral place in the world? This question strikes at the core of who we are, so to peer at it more carefully is of consequence to every person, if only to better understand ourselves.


Excerpted from my brain MADE ME DO IT by Eliezer J. Sternberg Copyright © 2010 by Eliezer J. Sternberg. Excerpted by permission.
All rights reserved. No part of this excerpt may be reproduced or reprinted without permission in writing from the publisher.
Excerpts are provided by Dial-A-Book Inc. solely for the personal use of visitors to this web site.

What People are Saying About This

Jerry Samet
At some point in our lives, we get puzzled about how we can be held responsible for actions seemingly initiated by brain chemistry. My Brain Made Me Do It is a terrific guide for those who are ready to confront this puzzle in its full scientific and philosophical complexity. It clearly explains the fascinating scientific advances in our understanding of the brain-behavior connection, and carefully considers their relevance to the free will question-making these complicated theoretical issues come alive in vivid case studies. (Jerry Samet, Professor of Philosophy and Cognitive Science, Brandeis University)
Joseph LeDoux
My Brain Made Me Do It is a fascinating and subtle account of the mysteries of free will, moral responsibility, and consciousness, topics that are among the most challenging facing neuroscientists, psychologists, and philosophers. (Joseph LeDoux, Professor of Neuroscience, Psychology, and Child and Adolescent Psychiatry New York University, author of The Emotional Brain and Synaptic Self)

Meet the Author

Eliezer J. Sternberg, MD, is a resident neurologist at Yale-New Haven Hospital. With a background in neuroscience and philosophy, he studies how brain research can shed light on the mysteries of consciousness and decision making.  He is the author of Are You a Machine? and My Brain Made Me Do It.

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