Monday, December 3, 2012

Does emotion really drive decisions?

I'm a pretty skeptical person. When I hear something that is counter intuitive, I typically don't believe it until I have some evidence that proves the concept is real.

In my study of engineering, economics, and decision sciences, I have been trained to apply logical analysis to decisions, and to block out the influence of emotions. If you're like me, then the idea that decisions and behavior are driven by emotion instead of reason is a tough pill to swallow.

But then I have read about two examples that provide compelling evidence in support of this concept. Antonio Damasio, a professor of neuroscience at USC, uses these stories to illustrate his somatic marker hypothesis, a hypothesized link between the frontal lobes, emotion and practical decision-making.
"Reduction in emotion may constitute an equally important source of irrational behavior."
- Antonio Damasio, Descartes Error

Phineas Gage and the Tamping Rod

Phineas Gage is often referred to as one of the most famous patients in neuroscience. He was a railroad construction foreman who survived an incident in 1848 where an iron rod was driven completely through his head. The injury destroyed portions of his brain's frontal lobe, an important part of brain that processes emotion and decision making. Before the accident, Gage was a responsible, intelligent, and likeable person. After the accident, he still had the same cognitive abilities as before, but he was irresponsible, used profanity extensively, and demonstrated no respect for social customs. His friends commented that “Gage was no longer Gage.” He could not hold the responsible jobs that he had before the accident and wandered around for the next several years. His decision making capability was severely impacted.

Portrait of Phineas Gage with his famous tamping rod.
From the collection of Jack and Beverly Wilgus.

Elliot and the Brain Tumor Surgery

Damasio tells a story about a patient named Elliot who lost a section of his prefrontal cortex during surgery for a brain tumor. Elliot went from being a successful businessman and father to losing everything. His IQ and memory were unchanged, but he became incapable of making the most basic of decisions. Damasio found that Elliott lost the ability to experience emotion as a result of the surgery. Intuition would lead you to believe that he would make better, more rational decisions. However, it was just the opposite. Without emotion, Elliot was unable to gauge what was important and what mattered. He deliberated over simple decisions, unable to reach a conclusion. Elliot's story is described by Jonah Leher in his article, Feeling our Way to Decision.

I found an interview with Antonio Damasio on YouTube where he describes what he has seen with patients that have lost their ability to experience emotion. Not only do they lose the capability to make decisions quickly, but they also make very poor decisions.