**The Iowa gambling test**
The Iowa gambling test reveals how the brain's emotional faculties drive decision-making and the weighting of risk and reward
The Iowa gambling test is an experiment in which a subject is shown four decks of cards on a computer screen and is asked to select a card. Each card has a monetary value on it which can be positive or negative e.g. +$500, -$100, +$50 etc.
Unbeknown to the the subjects, two of the decks are “good” and two are "bad". Picking cards from the "good" decks will overall result in a positive monetary total, while picking from "bad" will result in a negative one.
Researchers found that after playing for a while, people start to gravitate towards the “good” decks. This tendency is not the product of the subject's logic or memory. They aren't consciously choosing based on learned experience.
Rather, a look at their brain activity reveals that stress is the driver. The part of the brain that deals with stress activates when the participant hovers over the “bad” decks, encouraging them to pick from the “good” decks.
The amygdala is part of the limbic system and controls our response and memory of emotions, especially fear. When the experiment is rerun with people who have damaged amygdalae, brain monitoring shows no sign of stress when subjects hover over the “bad” decks. Without this emotional warning, the subjects continue to play the "bad cards" just as regularly as the “good” decks, resulting in a worse end position.
Here we see the subtlety of the link between our emotions and our actions at play in a situation of risk and reward. The rational brain would need to expend an enormous amount of energy, to observe and keep count of the relative success of picking cards from the different decks. It's our system 1's recall of emotion, not rational thought, which is driving us towards the most (emotionally) rewarding outcome.
