Why We Skip the Gym: Commitment Devices

How present bias makes people overestimate how often they'll exercise, and how commitment devices and incentives help people stick to plans.

Many people plan to exercise but don’t follow through.

Present bias

Present bias means we value immediate comfort over future benefits. Exercise costs effort now; benefits come later.

Overestimation

A famous study by economists Stefano DellaVigna and Ulrike Malmendier (“Paying Not to Go to the Gym”, 2006) found that monthly gym members attended so rarely that they paid more per visit than if they’d bought individual passes. They overestimated their future attendance.

Commitment devices

Tools that lock in future behaviour:

Pre-paying for classes.
Workout partners.
Betting money on reaching goals, through apps that take your money if you fail.
Public pledges.

Temptation bundling

Economist Katherine Milkman tested “temptation bundling”: allowing yourself a treat, like a favourite audiobook, only while exercising. It increased gym visits.

Incentives

Small payments for exercising can build habits, though effects may fade when payments stop.

The audiobook rule

A student only listens to her favourite thriller audiobook at the gym. Wanting to know what happens next, she goes more often.

Thinking people skip exercise only because they're lazy

Present bias affects everyone; commitment devices help.

Key takeaways

Present bias makes us favour comfort now over health later.
Gym members often overestimate attendance.
Commitment devices lock in future behaviour.
Temptation bundling and incentives can boost exercise.