Published on

May 12, 2023

Behavior Science 101: The 5 Most Important Concepts to Understand

"Behavior Science" has entered mainstream thinking, but it's still often explained through unnecessary jargon and inaccessible language. This article addresses that by giving a simple overview of this important topic and it's most key concepts. An 8 minute read.

Published by

Hugo Rourke

Behavior Science. It’s so hot right now.

In the last twenty years, the study of behavior science has moved from the ivory towers of academia and squarely into popular culture. 

If you’re in business, you may have heard pitches like “our team of behavior scientists will tailor your marketing to each individual.” In healthcare you might get “our behavior change AI triggers precision habits in unmotivated patients.” Even governments talk of “nudging people’s behavior” through population-level programs rather than through legislation.

It’s wonderful to see these ideas enter mainstream thinking. But it’s simultaneously frustrating that behavior science is often explained through economic theory, unnecessary jargon and inaccessible language. 

This article seeks to fix that. It covers five concepts that are foundational to understanding behavior science. From the irrationality of humans to how to motivate them, it gives an overarching view of this fascinating topic. Think of it as Behavior Science 101 with Prof Hugo.

And all that in just an 8 minute read! Let’s dive in.

Concept #1: Humans are all Crazy

The first (and most important) concept in behavior science is Behavior ≠ Rational Decision-Making. If you’re the parent of a teenager or live with a grown man who sulks when he drops his hot dog, you may already understand this. 

However, ALL humans are crazy. With enough time and mental bandwidth, humans can make one-off choices fairly rationally (e.g. deciding which cancer treatment to take based on various trade-offs). However, most of our everyday actions are ‘repeat’ behaviors that do not engage rational thinking. This occurs because humans don’t have the mental bandwidth to consider all choices all the time; it’s simply too overwhelming. Instead we use mental shortcuts and rely on ingrained habits, and so make predictably irrational behaviors.

What a terrifying concept. All you Rationalists out there lie down, take a deep breath and recite Pythagorus’ theorem until the world feels OK again.

The good news is that this realization - that humans are irrational in a myriad of ways - drove the development of a whole new domain of science over the last 50 years. That domain is called “behavioral science.”

Concept #2: Driving Behavior Requires 3 Ingredients

So what has behavioral science discovered over the last half decade? Have all those big brains come up with some kind of consensus on what drives human behavior?

Whilst there are numerous models with fun names like “B=MAP Fogg Model” or “B-COM”, the science is largely settled that three elements are needed to drive repeat behavior. These are:

  • Motivation - you need to want to do, ideally as keenly as possible
  • Ability - you need to be able to do it, ideally as easily as possible
  • Triggers - you need to recognise the opportunity to do it, ideally as timely as possible

When a behavior doesn’t occur, at least one of these elements is missing. It’s probably easiest to understand the interrelationship between these three using this fancy diagram from Mr Fogg:

The first thing to note in this diagram is that there is an “action curve” line. When a person is above this line and they get a prompt, the desired behavior is triggered. Below this line (the gray area) the trigger doesn’t work.

The action curve is defined by how motivated a person is, and their ability to do it; essentially is the task easy or hard.

Let’s say the behavior you want is for your child to empty the dishwasher when it’s clean. It’s an easy, 2-minute task so they’ll be to the right on ‘Ability.’

The 'Trigger' ideally would be the little beeps that the machine makes when it is finished, or it could be a subtle reminder from a parent, or it could be when they can’t find a clean plate.

But the 'Motivation' can vary. For example, asking “Can you please empty the dishwasher? It will make my life a little easier” is less motivating than “I’ll give you $5 every time you empty the dishwasher” or adding some social motivation to the incentive “$5 for you or your brother, whoever empties the dishwasher first.” 

High motivation plus an easy task puts your child in the “action” zone, so much so that it might feel like the dishwasher was unstacking itself, save for the $5 bills flowing out of your wallet.

Concept #3: Ability and How To Improve It

Let’s now take a look at Ability, which is a person’s capacity to do a certain behavior.

There is a common misconception in the behavior change industry that Education increases Ability. That is, when a person is educated on how to do a task they will find it easier to do. In this bucket we can put things like coaching programs or courses training new skills.

In healthcare, education could be sending emails that teach a patient the relationship between taking their blood pressure medications and the likelihood of having a heart attack. In our dishwasher example, education would be showing your child the best way to unpack the clean plates.

Whilst education is important, it’s not very effective at training repeat behaviors. In fact, according to Stanford’s Behavior Design Lab, education is the worst way to try to increase Ability. Ugh, those pesky folks at Stanford and their annoying research that undermines a century of health education campaigns.

Instead, the consensus is that 1) giving people the resources and tools to make it easier to do the behavior, or 2) re-designing the behavior so it's easier to complete are what’s needed to increase Ability. This puts the onus back on the designer - not on the user - to make the behavior or task easier to do. 

To go back to our dishwasher example… Is it possible to make unstacking the dishwasher any easier?

You could redesign your kitchen drawers so that your most frequently used cups and plates are stored nearest the dishwasher, thus minimizing unpacking distances. You could add tools like a cutlery caddy to carry more cutlery in small hands. Or even divide up your drawers with graphic labels so each item has a clear home to reduce the mental bandwidth for distraction-prone children.

Do all of the above and you’ll achieve far more than any weekly chore education campaign could ever achieve.

He must have read the brochure

Concept #4: Everyone is Motivated Differently

The fourth concept is about motivation. Motivation is multifaceted and what motivates varies from person to person. Fortunately, there is again pretty good consensus that there are three types of motivation:

  1. Intrinsic
  2. Extrinsic
  3. Social

Intrinsic motivations are those that bring a personal sense of achievement, rather than external rewards. When intrinsically motivated, a person is moved to act for the fun or challenge of a task; losing weight, moving up levels in a game or reading a new book every month. These motivations can be super-charged by giving people a way to see that improvement, like tracking their metrics or achieving streaks.

Like it says on the label, extrinsic motivations are rewards that are external to a person. These include going to work because you earn money, helping others in the hope of praise and going to the same store for the loyalty program rewards. You see that external rewards can be both self-incentives and also altruistic, and both have been shown to work time and time again. Some people worry about extrinsic motivators “crowding out” intrinsic ones. However, dozens of papers over decades of behavioral science research have shown this is often not the case, and indeed extrinsic motivators can set people up with initial motivation and formation of habits that then go on to help them achieve their intrinsic goals.

The third bucket, social motivations, work because humans are a deeply social species; working together has been the key to our evolutionary success. We love engaging with other people, feeling part of a community and being valued by our peers. There are many types of social motivations but a key one is the achievement motive, where we try to meet the standards of friends, family or culture. This can be triggered by being part of a community group of similar people, or establishing what the group is doing and how an individual compares with that.

Concept #5: Only Study Behaviors in the Real World

The last behavior science concept to understand is that it’s a discipline that has to be studied in the real world.

Well, this isn't going to go well

Humans are messy. The environments we move through are messy. Even my hair is messy most days. As a result, trying to improve human behavior using only a text book or talking about it theoretically with PhD peers does not work. Indeed this whole field started in response to seeing economic theory not match real-world observations.

Behavior change is an empirical science. This means it is based on “observation and experience.” Theories that have  been abstracted from observed results are useful as a starting point to design interventions. But ultimately the gold standard is in getting out in the real world with your clipboard and black spectacles, and observing how your intervention is performing in the real world.

A warning, there are also plenty of behavior change theories with little empirical evidence. While these theoretical models might seem attractive and no doubt look visually good on a chart at a conference, they are often quite useless in the real world.

The UK government learned this the hard way. They were frustrated by the results of their health initiatives based on such theoretical models. So the National Institute for Health and Care Excellence (NICE) conducted a review of the most frequently used health behavior change models. They found those models had only weak or small explanatory power in hindsight and little to no value in prospectively designing interventions. In layman’s terms, they all sucked and failed to perform

Thankfully, disappointed with the theoretical approach, NICE went on to commission a meta-analysis of empirically effective tactics for behavior change. They classified 93 effective BCTs (behavior change techniques) into 16 hierarchical groups, which was a huge step forward in understanding which BCTs actually work. Well worth a read with your cocoa in bed.


You are now armed and dangerous with the 5 basic concepts of behavioral science. While you might not yet have your PhD you are well on your way understanding that:

  1. Humans are inherently irrational, but Behavior Science has found predictable ways to influence behavior
  2. Motivation, Ability and a Trigger are needed to create a change in behavior
  3. Ability is improved by making a task easier (not through education), and
  4. Motivation can be Intrinsic, Extrinsic or Social, and everyone is motivated differently
  5. Only pay attention to behavior change interventions based on real-world evidence

If you want to read more on these topics, we recommend Predictably Irrational: The Hidden Forces That Shape Our Decisions by Dan Ariely, and How To Change: The Science of Getting from Where You Are to Where You Want To Be by Katie Milkman.

Habits and how they are used in business

Keep an eye out for the second article in the series; “The Science of Habit Formation.”

The majority of our day-to-day behaviors are subconscious, and if those behaviors are repeated regularly they become habits. Once a habit is formed that behavior is ‘locked in’ and very hard to undo, for better or for worse…

Businesses know this, so they put a lot of time and money into instilling habits to make you a loyal customer. In his next article Hugo pulls back the curtain on how 3 businesses do this.

About the author

Hugo Rourke has a lifelong passion for behavioral science, whether it’s through post-graduate study at Harvard or in practice at McKinsey. He has brought his experience to the field of healthcare as Co-Founder and CEO of Perx Health, a digital health company changing the way health plans engage with their high-risk members.

Perx Health enrolls a higher proportion of members, interacts with them more frequently and keeps them engaged for longer than any other digital health program. They achieve this by tailoring behavioral motivation strategies to the individual, ensuring the completion of 90% of critical daily care tasks like medication adherence, physical therapy and attending appointments. 

Perx Health has already helped over 30,000 patients achieve better health outcomes and partnered with over a dozen healthcare organizations. Email us to learn more. We're always happy to chat.

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