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Behavioral Insights: What is driving our actions?

An excerpt from Behavioral Insights, the newest edition in the MIT Press Essential Knowledge series

The MIT Press Essential Knowledge series offers accessible, concise, beautifully produced books on topics of current interest. One of our newest editions, Behavioral Insights by Michael Hallsworth and Elspeth Kirkman, is a definitive introduction to the behavioral insights approach, which applies evidence about human behavior to practical problems. The excerpt below is taken from the Preface and Introduction.

Explore the book below, or learn more about Behavioral Insights.


Many of us have suddenly stopped and asked ourselves, “Why did I just do that?” We may have paused, looked around, and realized that we made it halfway home while our thoughts were elsewhere. Or maybe we sat next to a purchase we now wonder if we really want or need, having been guided toward it effortlessly by prompts and reassurances.

These instances highlight that our behavior is often influenced by factors that lie outside our conscious awareness. This is not necessarily a problem; we would find it very hard to function if we had to consciously register and approve every single thing we do. But often we tend to underestimate the importance of this “automatic” side of our behavior–and so do governments or other organizations. The result may be ineffective policies, products, or plans.

While these automatic reactions take place outside of our conscious awareness, often they have developed as efficient and powerful ways to accomplish our goals. Consider how much more difficult our lives would be if we had to focus deliberately on each element of tying our shoelaces every morning, or to carefully weigh up the pros and cons of absolutely every food purchase we ever made. This kind of “fast” thinking is what allows us to make thousands of successful judgments and decisions every day, without even realizing we are doing so.

Nevertheless, our lack of awareness also has costs: it means that we usually do not recognize the way these processes are shaping our behavior. In one study, more than half of people who had been deliberately served between 500g and 1,000g of macaroni and cheese for lunch (over the course of a month) failed to notice that their portions had varied at all. Even if we do notice such things, we often come up with alternative explanations for our behavior. For example, we may claim that we ate more than usual because we happened to be particularly hungry. But the same studies show that’s not true: portion sizes, not hunger, caused the increased eating.

Whether we are examining food intake or any other kind of decision, the headline is this: if we do not understand our behavior accurately, then we are likely to adopt the best personal plans or public policies to achieve our goals. We will develop systems and strategies that depend on us pausing and deliberating when the evidence shows we will not. Behavioral insights can show us what is really driving our actions in these cases. In doing so, the approach provides explanations and predictions that guide us to more effective course of action.


Learn more about Behavioral Insights