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Neuroscience and the Law

The legal implications of mind reading.

The advances in the field of neuroscience during the last decade have been incredible. Increasingly, researchers are understanding the relationships between brain structure and behaviour, and are even starting to read our thoughts. But the improvements in technology are opening up a new range of questions. Just how good are we at reading minds? What can we really tell about both what people are thinking, and how their brain is affecting their behaviour?

These questions are particularly germane to the field of law. A fundamental legal issue is intent: whether or not someone willfully committed a crime. Another is the issue of truth, where knowing someone is lying is critical.

Dr. Owen Jones, from Vanderbilt University, is both a professor of biology and of law. He's closely watching both these fields to try and understand what happens when the two intersect. At present, it's complicated, as the science is maturing, but is still not able to provide definitive answers to legal questions.

One researcher who's developing techniques that are improving our ability to scan brains is Dr. Frank Tong, also from Vanderbilt University. Using techniques that measure changes in blood flow in the brain, he can tell which neurons are working when the brain is active. This technology can already be applied to lie detection, but Dr. Tong is moving beyond that. He's working to increase the finesse with which we can read the mind- looking for very small changes in brain activity. With his current technology he can tell the difference between whether someone's looking at a bird or a chair, but can't tell you what species of bird. It's possible that in the future he'll be able to tell finer details apart, which, from a legal perspective, would improve our lie detection skills.

The other big issue in criminal law is the question of motivation. Why did a person commit a crime? We treat people differently for crimes that are premeditated rather than accidental. The concept of accidental changes when a person has damage to their brain. If injury or disease has changed their personality are they responsible? And more fundamentally, can we even find biological links between behaviour and the brain. Dr. Marc Hauser, a Harvard College Professor, was part of a team that recently documented one such link. They described an area of the brain that, when damaged, impaired a person's ability to make certain decisions that relied on a sense of morals. As we find more of these examples, this will help judges and juries decide responsibility.

Not everyone's convinced we should be rushing to get this evidence into the courtroom. Dr. Lesley Fellows, an assistant professor in the Department of Neuroscience and Neurology at McGill University, doesn't disagree that biology and behaviour are linked, but does think the science isn't mature enough yet to be used as evidence in a trial. For now, it's more applicable in clinical settings, to look at understanding why people commit crimes, rather than to predict whether or not someone is a criminal.

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Related Links

Dr. Hauser's homepage
Dr. Fellows' homepage
Dr. Jones' homepage
Dr. Tong's homepage
An overview of the issue by Dr. Jones
Dr. Hauser's paper in PNAS on neurobiology and morality
Dr. Hauser's paper in Nature on neurobiology and morality

Limb loss in Lizards

Unprepared Adriosaurus microbrachis - Courtesy, University of Alberta

Some things in nature are hard to fathom. You'd think if a species were evolving from walking on four legs, to slithering on none, that either all four legs would be lost at the same time, or the back legs would disappear first. After all, it's easier to pull a piece of string than push it. But that's not the way it happens. In species that evolve to lose their limbs, it's the front legs that go first. A newly recovered fossil, Adriosaurus microbrachis, shows that this type of evolution has been going on for more than a hundred million years, back to the first days of the evolution of snakes. Dr. Michael Caldwell, from the University of Alberta, uncovered this fossil, providing a missing link in legless evolution.

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Related Links

Dr. Caldwell's homepage
The University of Alberta version of the story

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Ice Age Impact

Asteroid impact - Courtesy, NASA

The mystery of what killed the Mammoths and other ice age animals of North America has a new suspect. In fact, it may be a serial killer, since it's the same suspect implicated in the demise of the Dinosaurs. Dr. Luanne Becker, a geochemist at the University of California at Santa Barbara, thinks she has evidence that an asteroid struck the ice sheet that covered Canada about 13,000 years ago. She thinks this impact, which would have been smaller than the one that killed the dinosaurs, would still have been large enough to cause major fires and climatic disruption resulting in the loss of a whole group of large Ice Age mammals.

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Related Links

Abstract for Dr. Becker's paper next week at the Meeting of the American Geophysical Union
Dr. Becker's Web site

Frog Poison

Poison frog with a bunch of mites - Courtesy, Ralph Saporito

When it comes to their place in the food chain, frogs aren't at the bottom, but they're certainly not at the top either. Yet a certain group of frogs in Costa Rica, called poison frogs, has found a way to turn this middle ground into an advantage. While many animals produce poison as a defense, these frogs cannot. Instead, they've found a way to steal the poison from the food they eat in order to prevent themselves from being eaten. For years, scientists thought that frogs were only stealing these poisons from ants. But Ralph Saporito, a graduate student at Florida International University, decided to look closer. What he found was a whole new source of toxic chemicals that the frogs sequester from mites.

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Related Links

Ralph Saporito's Web site
Link to study in PNAS