Big Idea: Deep Rationality

This idea was contributed by Big Think Delphi Fellow Douglas Kenrick.

What’s the Big Idea?

A new model for understanding human decision-making, called Deep Rationality, acknowledges the irrationality of human decision-making but suggests that it might be rooted in evolution.

Why Is It Groundbreaking?

In the great tradition of the Enlightenment, classical economists once believed that the human mind was gloriously, and perfectly logical, and that the decisions it made were equally sound. Behavioral economists overturned this theory in favor of a darker idea – that humans are essentially irrational idiots, processing tiny bits of information at a time and stumbling more or less by accident through life. But this new perspective, based in evolutionary economic theory, infuses the discussion with a bit of the old enlightenment faith in human ability.

Deep Rationality, as Big Think Delphi Fellow Professor Douglas Kenrick of Arizona State University calls it, acknowledges the behavioral economics belief that “consciousness is limited.” But it then goes on to borrow from neuroscience and psychology the idea that there is much more going on beneath the surface.

According to this model, the brain processes far more than the conscious mind could do alone, and although the conclusions each of us draws may occasionally appear irrational, they “on average, would have resulted in fitness benefits” for the species as a whole. In other words, seemingly irrational behaviors today might have been highly rational to our ancestors, helping them to survive and to breed. 

Why Should You Care?

The first step in changing behavior is understanding what drives that behavior in the first place. “If we realize that an evolved mechanism can steer us wrong in the modern world, we can use conscious processing to over-ride,” says Kenrick. He cites our preference for fatty, high sugar foods, inherited by ancestors who had difficulty procuring such fare, as an example. Although the trait once served humanity in its quest to survive, it is outdated. 

“It seems to me that a lot of the problems of the modern world are because we are designed to live in a different world. I think that although a lot of our programming was adapted for our ancestors, it doesn’t always fit in the modern world.”