64 Thinking Fast in a Complicated World

Economics often imagines decision makers as calm and calculating. They know what they want. They compare options. They choose what maximises their benefit.

But most real decisions do not happen like that.

They happen in supermarkets, on phones, late at night, under time pressure, surrounded by noise, notifications, and uncertainty. People rarely optimise. They cope.

This is where behavioural economics begins.

Rather than assuming perfect rationality, behavioural economics starts from a more honest place. Human beings have limited attention, limited time, and limited cognitive capacity. We cannot process all available information, even when it is technically accessible. Instead, we rely on heuristics, simple rules of thumb that help us make decisions quickly.

Heuristics are not flaws. They are survival tools.

If every choice required full optimisation, everyday life would grind to a halt. Choosing a meal, a route to work, or a product online would become exhausting. So the brain shortcuts.

Sometimes these shortcuts work remarkably well. For example, investors who spread their money equally across different assets often perform as well as, or better than, those following complex optimisation models. Simplicity can outperform sophistication.

But heuristics also create predictable patterns of error.

People judge likelihood based on stories rather than statistics. They confuse what feels representative with what is actually probable. They overestimate rare risks and underestimate slow ones. They mistake confidence for competence.

One famous illustration involves a fictional woman named Linda. When told a story that fits a familiar stereotype, many people judge a more detailed description to be more likely than a simpler one, even though this is mathematically impossible. The story feels right, so it overrides logic.

These are not individual quirks. They are systematic tendencies. And once they are understood, they can be anticipated.

That insight changed economics forever.

Because once behaviour is predictable, it becomes steerable.

Further Reading and Exploration

• Kahneman, D. (2011), Thinking, Fast and Slow

• Simon, H. A. (1957), Models of Man

• Gigerenzer, G. (2007), Gut Feelings: The Intelligence of the Unconscious

• Gigerenzer, G. and Brighton, H. (2009), “Homo Heuristicus”, Cognitive Science

• Thaler, R. (2015), Misbehaving