Study: Intuition Crucial In Making Sensible Decisions -- Area Of Brain Linked To Hunches

Neuroscientists Thursday reported compelling new evidence that intuition plays a crucial role in helping people make sensible decisions and provides clues to how "gut feelings" work in the brain.

An unusual experiment that compared normal people to those with a specific type of brain damage as they gambled with cards identified a part of the brain that appears necessary for intuition to work, the researchers said.

"We all have examples in our own life where we talk about hunches and gut feelings," said Antonio Dimasio of the University of Iowa College of Medicine, who led the research. "What we were trying to do was get underneath a gut feeling or a hunch."

The findings, published in Friday's issue of the journal Science, may help dispel notions that emotions are unimportant, Dimasio said. "It's an artifact of the hyper-rationalist modern times that we live in that we have become distrustful of intuition," he said.

In the study, the researchers examined 10 normal people and six people who had suffered damage to a brain area called the ventromedial sector of the prefrontal cortex, which is involved in decision-making. Such brain-damaged people have normal intelligence and memory but show little emotion and have trouble making sound decisions.

The researchers gave each of the 16 participants $2,000 in fake money and four decks of cards, and told them they could turn over cards from any deck. They would lose or win depending on the cards they turned up.

Unknown to participants, two decks were stacked to make players lose overall if they picked from those decks, even though those decks would produce payoffs at first. Although the two other decks paid off less at first, they produced winners overall.

Subjects had sensors attached to their skin to detect imperceptible sweating that indicates anxiety. The researchers stopped the game after each subject had taken 20 turns, and then after every 10 turns, to question participants and determine when they became conscious of the best strategy to win.

After losing a few times, the normal people began to show signs of anxiety before picking cards from the losing decks. The subjects also began avoiding those decks well before they consciously became aware that they were losers.

"By about card 50, all normal participants began to express a `hunch' that decks A and B were riskier, and all generated anticipatory (sweating) whenever they pondered a choice from deck A or B," the researchers wrote.

By their 80th turn, seven of the 10 normal participants consciously knew how to win by avoiding the losing decks.

"Remarkably, the three normal participants who did not reach the conceptual period still made advantageous choices," the researchers said, demonstrating that intuitive knowledge was influencing behavior.

In contrast, the brain-damaged people never showed physical signs of anxiety, never expressed a hunch that some decks were losers and continued to pick from the losing decks, demonstrating that they had been unable either to form or gain access to intuitions.

The researchers concluded that normal decision-making requires two "parallel but interacting chains of events." One involves activating a brain circuit that includes the ventromedial frontal cortices, which store knowledge about a person's emotional experiences - his or her intuition.

In normal people, the researchers said, that part of the brain sends signals to other parts of the brain, which recall the overall facts of a situation, including various options and possible outcomes, and use the unconscious knowledge - the intuition - to make the right decision.