mind rewriting this statement by one of your colleagues? You do not have to put your name to the anti-American statement, nor tell anyone else of your actions. The Chinese found that this simple step was an important one on the road to collaboration. After a prisoner had taken this act, he was much more likely to begin making his own statements against the United States.15 It seems that simply getting the brain to say or write something begins to change attitudes. A similar logic underlies Dale Carnegies suggestion to get the other person saying, yes, yes immediately.

None of these examples prove that the subconscious is important. Perhaps Professor Marvin Minksy was simply lazy on the morning of his scheduled breakfast with President Ford. Similarly, we cant know for sure why my grandfather was able to stop my hiccups or why saying or writing something changes our opinion. For proof of cause and effect we need to reenter the scientific world.

Studying with people who have some sort of impairment sometimes provides insight into the brains normal function. In our quest to understand split-brain influences, we can learn from people who literally have split brains. In most people the left and right sides of the brain talk to each other via the corpus callosum, which physically connects the two halves. Some people are born without a corpus callosum, and thus the left and right sides of their brains do not know what is going on in the other side. Studies of people with these split brains reveal that conscious parts of our brain are not always in charge. These investigations are described at length in a number of excellent books, including Professor Michael Gazzinigas The Minds Past.16

To investigate brain function, scientists presented signs with written instructions to these patients with split brains. For example, the sign might have said, Please wave now. The patients would comply with these requests.

The interesting aspect of these split-brain studies came when the patients were asked to explain their actions. The scientists made sure that the signs were only seen in the left visual field where it would only

register in the right half of the brain. They made sure that the left hemisphere of the brain, which controls speaking, did not see the requests. Because the brains of these patients were split, one half of the brain knew that the waving was a response to a request. The other half of the brain was completely ignorant of the cause, and this half had to explain the waving.

Why are you waving? Now the speaking part of the brain is faced with a dilemma. It has no information about the cause of the waving. Nevertheless it can sense that the body did just wave. Rather than confess to its ignorance, the language part of the brain makes up a story. For example, it might say, I thought I saw someone I knew. Similarly, when half the brain is instructed to laugh, the ignorant half of the brain makes up an explanation like Im laughing because you are funny guys.

These studies and others lead to a startling conclusion. We are built to cover up the fact that the lizard brain influences us. When we think we have decided to take an action with our rational brain, we often have simply made up a story for the cause of action. As with Professor Minsky, parts of our brain outside the prefrontal cortex often set the course and leave the explaining to other parts.

Another interesting set of studies reveals the limits of our conscious brain. This phenomenon is known as the McGurk effect; if you search the web you should be able to experience it yourself. The McGurk effect demonstrates that before sensations become consciously aware, they have been altered by the nonconscious brain systems. Heres how it works.

When we listen to others speak, we use both our eyes and our ears. This is true even for those of us who have not been trained as lip-readers. In 1976, Harry McGurk and John MacDonald demonstrated this in the following manner. Professors McGurk and MacDonald tape-recorded a person producing the sound Ba and then combined that sound in a precise manner with a film of the same person saying Ga. 17

What do you perceive when you hear the sound Ba while watching lips making the shape of Ga ? The answer is a fused sound best

described as Da. The most interesting aspect of the McGurk effect is that it never goes away. If you watch the video with your eyes closed, it is clear that the sound is Ba ; opening your eyes produces Da. Even after watching the tape for hundreds of times, and even knowing the true sound, the effect exists. We cannot use our rational brains to override the nonconscious preprocessing of the information.

The McGurk effect demonstrates that preconscious processing affects our fundamental perception of the world. Obviously, the prefrontal cortex cannot be in complete control if it has information that is altered and shaped by the other parts of the brain.

What have we learned so far? If we divide the brain into the prefrontal cortex and the lizard brain, we have seen that our prefrontal cortexes are often far from perfect. Next, we have seen that the lizard brain has a powerful influence on our behavior. We are built to make errors and fall into a variety of traps. Finally, we are built to create a cohesive story about our behavior, which makes it hard to understand the sources of our own actions.

The Lizard-Brain Goes to Wall Street

Democracys the worst form of government except for all the others, said Winston Churchill. Similarly, rational investing, using our less than perfect analytic system is the worst way to make money except for the alternative of using our lizard brains. As we will see, the lizard brain pushes us toward destructive acts.

The only thing worse than having a flawed prefrontal cortex exerting weak control is not having the prefrontal cortex in charge. The most famous example of this comes from the sad tale of Mr. Phineas Gage. The incident happened on September 13, 1848, and the original newspaper article in the Free Soil Union tells the story.

Phineas P. Gage, a foreman on the railroad in Cavendish was engaged in tamping for a blast, the powder exploded, carrying an