Behavioural economics
Behavioural economics studies how real human psychology, with its biases and limits, departs from the rational model of choice.
For most of its history, economics assumed people were rational calculators. Behavioural economics is what happened when economists started watching what people actually do.
Behavioural economics studies how real human psychology, with its biases, limits, and quirks, shapes economic decisions, and how systematically those decisions depart from the rational model that standard economics assumes. It marries economics with psychology to describe choice as it is, not as the textbook supposes.
Against the rational actor
Conventional economics built its models on a tidy fiction: a rational agent with stable preferences, unlimited computational power, and pure self-interest. The fiction was useful and often predictive, but it failed in patterned ways. People value losses more than gains, are swayed by how options are framed, weigh the present far above the future, and care about fairness. Behavioural economics took these not as random noise but as regularities worth modelling.
Predictable irrationality
The field's central finding is that human deviations from rationality are not chaotic but systematic and therefore predictable. Anchoring, loss aversion, overconfidence, and the rest recur reliably across people and settings. That predictability is what makes the deviations useful rather than merely interesting: if errors followed no pattern they could not be modelled, but because they do, they can be anticipated, designed around, and sometimes exploited.
Influence and its temptations
Behavioural insights have reshaped policy and business, from default enrolment in pension schemes to the design of choices that gently steer behaviour. This power cuts both ways. The same understanding that helps people save more or eat better can be turned to manipulating them into spending, clicking, or consenting against their interest. The knowledge is neutral; its use is not.
Behavioural economics did not overturn economics so much as make it more honest about its subject. It keeps the rigour of the older approach while replacing the cartoon of the perfectly rational agent with something closer to the strange, biased, but patterned creature that actually makes the decisions economies are built from.