Necessary or Rewarding
Humans only move when movement is required of them or feels good - so engineer one or the other deliberately.
- Difficulty
- Moderate
- Time to result
- ~months to results
- Steps
- 5
- Confidence
- 92%
Lieberman's central behavioural claim is that humans evolved to be physically active for exactly two reasons: when it is necessary, or when it is rewarding. For most of human history necessity did the work - farming, hunting, gathering and walking 5 to 10 miles a day left no choice. Modern life removed the necessity, and the instinct to conserve energy when possible is normal rather than lazy. The framework says stop relying on willpower and instead deliberately rebuild one of the two evolved conditions: make the activity structurally unavoidable, or make it socially rewarding enough that you want it. Lieberman's research now points to the social dimension as the strongest lever for most people.
Origin
The idea crystallised for Lieberman in Mexico while collecting data on the Tarahumara. Interviewing a famous 70-something distance runner about how he trained, he discovered the language has no word for training, and the man's tone conveyed bafflement: why would anybody run if you did not have to? Lieberman realised that voluntary exercise is the historical anomaly, which forced him to ask what actually produced movement before gyms existed.
Core principles
- 01The urge to take it easy is an instinct, not a character defect.
- 02People are physically active for two reasons only: necessity or reward.
- 03Modern environments deleted necessity, so reward has to be manufactured on purpose.
- 04For most people the reward is social rather than physical.
- 05A commitment made to another person survives the moment when motivation does not.
- 06Shaming people for taking the escalator attacks a normal instinct and changes nothing.
How to run it
- 1
Diagnose which lever is missing
Ask honestly whether the activity you are failing to do is currently necessary, currently rewarding, or neither. Almost all abandoned exercise plans are neither, and are running purely on willpower.
Watch out Do not skip to tactics. Choosing a reward mechanism when what you actually need is enforced necessity is how programmes fail twice.
- 2
Manufacture necessity where you can
Build structures that remove the choice: a standing commitment at a fixed time, a scheduled slot that others depend on, a company or household rule, or a rule of your own that you do not permit yourself to break - Lieberman refuses to take an escalator unless he has to.
Pro tip Necessity works best when someone else notices your absence, which is why fixed-time group formats outperform flexible solo plans.
Watch out Imposed necessity has a cost. When the Bjorn Borg CEO mandated exercise, some employees quit.
- 3
Build the social reward deliberately
Attach the activity to other people: a running partner, a group of friends, a team, a class, or dancing - which every culture on earth has and which nobody thinks of as exercise. The friends supply the pull on the mornings when your own motivation does not.
Pro tip Lieberman meets a friend at 6am on a specific street corner. The specificity of the arrangement is what makes it survive the moment he would rather stay in bed.
- 4
Add explicit accountability if the social pull is not enough
Nominate a referee - a friend, partner, parent or paid trainer - who tracks whether you did it. A trainer is, in Lieberman's framing, essentially a mechanism for making you accountable.
- 5
Expect the intrinsic reward to arrive late
Plan for the dopamine response to be absent at the start. If you are unfit or overweight you are relatively insensitive to it, and Lieberman says it can take months or years before a run feels good. The external structures from steps 2 to 4 are what carry you until then.
Pro tip Anything is better than nothing - taking the stairs in your building counts, and the pathway eventually becomes self-rewarding.
Watch out Judging the plan by whether you enjoyed it in the first weeks will make you quit at exactly the point the framework predicts no enjoyment.
In the wild
Lieberman arranges to meet his friend Aaron at 6am on the corner of Mass Ave and Linnaean. He is explicit that the evening before it seems like a great idea, and that at 6am he wants to stay in bed with his wife rather than meet a nasty smelly guy in the cold and dark. He goes anyway, because he agreed to.
→ The run happens on mornings where motivation alone would have failed, and he reports he is usually glad he did it afterwards.
Searching for any company that had made physical activity necessary rather than optional, Lieberman found the Bjorn Borg sports company in Sweden, whose CEO requires every employee to exercise during a sports hour every Friday at 11am. He emailed the company's contact form, was invited by the CEO, flew to Sweden and observed the sessions and interviewed staff across the business. Rank is irrelevant: mail room, CEO or visiting board member, if you are there on Friday you exercise.
→ A number of employees quit when the policy was introduced, but almost everyone remaining told Lieberman it was a pretty damn good thing.
Rather than mandating exercise, Bartlett's roughly 30-person team runs a fitness channel in Slack and the company enables and promotes whatever employees start - a women's football team, a men's football team, a reading club - and pays for costs such as kits and uniforms.
→ Bartlett reports gains in staff retention, connection and community, achieving a reward-side version of the same goal without the resignations that the mandate produced.
Common mistakes
Relying on willpower as the primary mechanism
Willpower is being asked to overcome an evolved instinct to conserve energy, every day, indefinitely. The framework exists precisely because that contest is lost by most people most of the time.
Calling yourself or others lazy
Lieberman is explicit that the people queueing for the escalator are not lazy, they are being normal. Framing it as a moral failing produces shame, and shame demonstrably does not produce movement.
Choosing an activity you do not like because it is optimal
Lieberman's answer to 'what is the best exercise' is the one you like doing. An optimal protocol you find unrewarding removes the only lever you have left once necessity is gone.
Expecting to enjoy it immediately
Unfit and overweight people do not get the dopamine hit that fit people get, and are then made to feel bad for not enjoying it. Building a plan that assumes early enjoyment guarantees an early quit.
Is it for you?
Best for
Anyone who has repeatedly started and abandoned an exercise habit, and leaders or managers designing conditions that get a group of people moving.
Not ideal for
Already-consistent trainees looking for programming or performance optimisation - this framework is about getting movement to happen at all, not about what to do once it does.
From the transcript
“people evolved to be physically active for two reasons and two reasons only. When it's necessary or rewarding. When we don't make it necessary, we…”
“the more I study it, the more I think it's social.”
“the evening before it seems like a great idea to meet Aaron at 6:00 a.m. on the corner of Mass Ave and Linnaean. The next…”
“those people taking the escalators, nothing wrong with them. There's they're not lazy. It's just an instinct, right? It's an instinct to take to take…”
“nobody thinks of dancing as exercise but it's exercise, right?”
From the episode
Harvard Professor: "10,000 Steps A Day" Is A LIE! Revealing The 7 BIG LIES About Exercise, Sleep, Running, Cancer & Sugar!!! Daniel Lieberman
Harvard Professor