Nudge, Nudge, Wink, Wink

Passing a smaller plate to someone wanting to lose weight – that’s a nudge. The well-known fly in the urinal, that originated in Schiphol Airport in Amsterdam and is now found in urinals all over the world, is another nudge. Nudges can get people acting in a certain way, without the need for direction, coercion or oversight from us.

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This Pivot: The two ways we all think, and how we can use one of them to influence the behaviour of others.

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When it comes to eating less, researchers have long known that a simple way to cut calories is to use a smaller plate. In one experiment, conducted by Brian Wansink from Cornell University and Koert van Ittersum from the Georgia Institute of Technology, it was discovered that a shift from 12–inch plates to 10–inch plates resulted in a 22% decrease in calories. Assuming the average dinner is 800 calories, this simple change would result in an estimated weight loss of more than 10 pounds over the course of one year. - James Clear

Passing a smaller plate to someone wanting to lose weight - that’s a nudge.

The well-known fly in the urinal, that originated in Schiphol Airport in Amsterdam and is now found in urinals all over the world, is another nudge.

Pre-selecting tick box options on a form is another.

Nudges can get people acting in a certain way, without the need for direction, coercion or oversight from us.

Nudge Theory

Nudge Theory is a collection of ideas put forth by Thaler and Sunstein in their 2008 book, Nudge: Improving decisions about Health, Wealth, and Happiness.

A nudge, as the term is used in the book, is “any aspect of choice architecture that alters people’s behaviour in a predictable way, without removing any options or significantly changing their economic incentives”. Thaler and Sunstein describe a ‘good’ nudge as one that encourages a particular choice, but is still:

  • Transparent. There is no hiding of the other options.
  • Not compulsory. The person is still able to make another choice.
  • Benevolent. There is a good reason to believe that the nudge is worthwhile for the person being nudged.

A test for a 'good' nudge is whether it will work even when people know they are being nudged, and why (by contrast, a manipulative nudge will generally not work once its secret is revealed – sneaky pre-ticked extra charge options by airlines is an example).

To count as a nudge, an intervention must be cheap and easy to avoid.

Why Do Nudges Work?

To see why nudges work, we need to understand how humans think.

The workings of our brains are somewhat bewildering! On the one hand, we can be rational and calculating in our decisions, considering all the alternatives. At the other extreme, we can forget what we went into the other room to get, or why we went to the supermarket. How can we simultaneously be so smart and dumb?

The answer lies in our two kinds of thinking. There is an emerging consensus among psychologists and neuroscientists that we do have two thinking systems: one that is intuitive and automatic, and one that is reflective and rational.

Automatic thinking is believed to be associated with the oldest parts of the brain. It’s what happens when we duck when a ball is thrown unexpectedly, hold out our hand when someone offers to shake hands, or smile at a baby. It’s thinking without thinking.

We can activate reflective thinking at will. It is deliberate and self-conscious; it’s when we are aware that we are thinking. We use reflective thinking when we solve a difficult maths calculation or decide where to go for our vacation. It’s when we analyse and make judgements.

Reflective vs. Automatic

When we speak in our own language, we use our automatic thinking; when we speak in another language we use reflective thinking (genuinely bilingual people use their automatic thinking for both). When we are accustomed to a system of measure (kilometres, kilograms) we use our automatic thinking. We need our reflective thinking to comprehend measurements in another system (miles, pounds).

Although the reflective system might seem superior to the automatic system, it really isn’t. The reflective system is simply too slow and too single minded to handle even a fraction of the alternatives we are faced with every day. The automatic system can handle thousands of problems and alternatives for us without even bothering us with the outcomes.

The two systems generally work well together, allowing us to act quickly and instinctively when required or to call up deep, powerful thought - but they don’t always work well together. The automatic system can even cause the reflective system to falter.

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Examples (try to answer in under 3 seconds):

  • A bat and a ball cost $1.10 in total. The bat cost $1 more than the ball. How much does the ball cost?
  • If it takes 5 machines 5 minutes to make 5 widgets. How long will it take 100 machines to make 100 widgets?
  • If the lily pads in a lake double in size every day, and it takes 48 days to cover a lake, how long will it take to cover half the lake?

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(The answers are - 5 cents, 5 minutes and 47 days.)


Our automatic thinking system is prone to bias. In fact it uses bias to speed up reasoning. But it’s those biases that allow nudges to work.

There are seven kinds of biases referenced in Thaler and Sunstein’s book:

  • Anchoring. Where we rely too heavily on the first piece of information offered (the "anchor") when making decisions. The initial price offered for a used car sets the standard for the rest of the negotiations.
  • Availability. Where we rely on immediate examples that come to our mind when evaluating a specific topic, concept, method or decision. Murders are more sensational (available) than suicides so we think (wrongly) that more people die from homicides.
  • Representativeness. Where we categorise a situation based on a pattern of previous experiences or beliefs. We believe that a very tall person is more likely to be a basketball player than a short person.
  • Optimism and Overconfidence. Where we feel we are better than average and bad things are not going to happen to us. We believe that we are an above average driver, that we have an above average sense of humour, and that we will not get a serious disease.
  • Gains and Losses. Where we hate to give up what we have. As a rule of thumb, losing something makes us twice as miserable as gaining the same thing makes us happy. We have a strong desire to stick to what we already have.
  • Status Quo. Where we want to stick with our current situation. We tend to sit in the same seats in a meeting, and we somehow don’t get around to cancelling that subscription we no longer need.
  • Framing. We reach decisions based on the framework within which the information is presented to us. ‘Of one hundred patients who have this operation, ninety are alive after five years’ gets quite a different reaction in research to the statement, ‘Of one hundred patients who have this operation, ten are dead after five years’.

Other writers add another bias:

  • Social Norms. Where we don’t want to be different from everyone else. Research has shown that people have been made to make obvious errors simply because all the people (actors) before them made the same mistake.

Our automatic thinking system uses these biases to help us make unconscious decisions quickly and with limited effort.

But it’s because of these biases that we can be ‘nudged’.

How Might We Use Nudges?

Keeping in mind our earlier definition of a ‘good’ nudge (one that encourages a particular choice in a way that is transparent, not compulsory and benevolent), how might we ‘nudge’ our parents and caregivers into, say, being more consistent when signing their child in and out of the centre?

We could consider setting up our ‘choice architecture’ in such a way that it makes it easy for the automatic thinking system, while reducing the amount of reflective thinking necessary.

  • We make sure our sign-in sheets are right in the path of people arriving, and in a distraction free area. We make signing in a habit (walk in, sign), putting the status quo bias to work for us.
  • We make sure there is a tethered pen that works (no interruption of the automatic thinking system to find a pen).
  • We locate a digital clock right by the sign-in sheet (no reflective thinking to convert a regular clock to a number to write down).
  • We highlight those who didn’t sign in in the morning so it is obvious they need to sign both in and out at the end of the day (social norm bias).
  • We replace our sign “Please sign your child in” with “XX% of our caregivers always sign in, please help us reach 100%!” (social norm bias).

The power of nudges comes from recognising that people cannot make all their decisions throughout the day in a carefully considered, rational way.

In fact, most decisions are done using the automatic thinking system.

Sometimes we can use that to our advantage.


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Food for Thought…

  • We all have two kinds of thinking: automatic and reflective.
  • Reflective thinking can be called upon at will and we use it to consider and calculate.
  • Automatic thinking makes most of our decisions for us every day.
  • Automatic thinking is prone to bias.
  • We can use our knowledge of human thinking and biases to ‘nudge’ people toward actions.


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