Why Confident New Members Quit First
Cary Deck and Klajdi Bregu wanted to know whether overconfidence shortens the time people stick with a hard task. Overconfidence in gym members is common, and is the thing Silicon Valley backs. Moreover, in the gym industry it’s what every sales pitch in January is designed to inflate. What Deck and Bregu ran was a clean lab experiment. They tested whether the same asset gets you through week six.
Participants got puzzles first. The difficulty was tuned so they’d get roughly a third right, because Moore and Healy had already shown that’s where people reliably overrate themselves. Then came the part the study was actually built around. It was a second task where success was uncertain, and each participant chose how long to keep trying before walking away.
The participants who rated themselves highest on the first task quit the second one soonest.
The standard fitness-industry script runs the other way. Belief fuels persistence. You have to believe you can do it before you can do it. Gym operators have been selling that line since the eighties. The confident participants in Deck and Bregu’s study had fully bought it. They’re the ones who walked.
When people do not know whether a goal is actually achievable, overconfidence causes them to give up sooner. Early failures get interpreted as evidence the goal was never possible, which shuts the attempt down. The most self-assured new gym member is often the one who cancels first.
The study
Their paper, in the 2025 Southern Economic Journal, starts with a theoretical point. When you’re trying something and you don’t know whether it’s actually doable for someone like you, every failure is ambiguous. Maybe you’re not capable enough yet, or maybe the thing can’t be done at all. The more confident you are in yourself, the harder it gets to pick the first reading. So you pick the second, and then you stop trying.
In the data, participants who overrated themselves on the puzzles gave up sooner on the second task than participants who had a realistic read on their own performance. Risk aversion pushed the other way. Some people kept trying because they didn’t want to be the person who bailed, and that blunted the effect. However, it didn’t reverse it.
Puzzles aren’t barbells, and the gap between a lab chair and a squat rack is real. What carries across is the underlying shape. A person facing a goal they don’t know is achievable for their particular body, while holding a high opinion of that body, is the position every new member sits in during week one.
The Discouraging Effect of Overconfidence
When someone doesn’t know whether a goal is achievable for them, being overconfident makes them quit sooner than a realistic person would. Each failed attempt gets read as evidence the goal was never possible, so they stop before more effort would have changed the outcome.
Why this runs backwards from the gym industry’s worldview
Most gym marketing sells one idea. Believe you can change your body, and your body will follow. Every transformation post and hype video on the feed is trying to pull that one lever.
Deck and Bregu aren’t saying belief is worthless. They’re saying belief works differently when the person holding it doesn’t know if the goal is actually reachable for them. In that situation, inflated belief doesn’t push you through the wall. It helps you walk away from it.
When someone believes they’re the kind of person who follows through and gets results, they’ve already narrowed where they’ll place the blame if progress disappoints. An honest reading of a slow week six has some obvious internal options on offer: your effort, your consistency, how well you recovered. A confident member has fewer of those available to them, because the confident self-image doesn’t sit comfortably next to “I didn’t try hard enough.” Blame gets routed externally instead. The 2kg on the scale where 10kg was supposed to be becomes a verdict on the program, not the person.
The sentence the member arrives at, usually silently, is that this kind of program doesn’t work for their kind of body.
They leave still thinking well of themselves. The cancellation email to the studio is polite, frames the issue as a fit problem, and never mentions that preserving the self-image is the actual reason they’re going.
The person you know
You know the one. They signed up in January with the energy of someone who had already seen the before-and-after photo in their head. The early questions were about protein and progression. The posts were about the whole project of becoming this new version of themselves. Week three they were still showing up. Week five they were asking thoughtful questions about creatine. Week seven, the gym went quiet on their social feed. Week nine, the key-card stopped appearing in the scanner. Week ten, a polite cancellation email said the program wasn’t quite the right fit for where they were in life.
Notice the language they reach for when they cancel. It points outward, every single time, at the program or at their expectations or at their body refusing to respond. What they almost never land on is that they did not show up enough.
The quieter member is the one who joined without a story attached and without expecting much, and they’re still there on Wednesday mornings. It’s not that they’re more committed. They came in without a prediction, so reality has nothing to underperform. Therefore, a slow week just means a slow week. “This is slow” never has to become “this cannot be done.”
Deck and Bregu studied puzzles, and their participants never touched a barbell. But the mechanism they described is the same one that hollows out your Wednesday six a.m. class between February and April, year after year.
The nuance
Confidence on its own isn’t the problem. What turns fragile is the specific combination of high self-assessment plus real uncertainty about whether the goal is doable for you. A member who has been lifting for two years knows how their body responds to a given program. So there’s no real uncertainty in their picture, and their confidence gets to function the way the motivational industry advertises.
None of this says the fix is to crush new members’ expectations at the sales desk. “Most people fail at this” isn’t a useful onboarding line, and that kind of framing has its own backfire problem. The issue sits further upstream. When a gym sells certainty, it hands the new member the exact combination Deck and Bregu warned about. That is strong belief about what’s achievable paired with no actual evidence the goal is achievable for them.
Risk aversion also muddies the picture. Deck and Bregu found participants were overly reluctant to try the innovation task even when trying was the rational move. That reluctance can coexist with overconfidence inside the same person. This means a new member can be simultaneously too sure they’ll succeed and too afraid of looking foolish if they don’t. A gym owner watching that member hesitate, then overreach, then quit isn’t watching one bias run its course. Instead, they’re watching two biases decide which one gets to end the membership first.
Research summary
| Study | Context | Finding |
|---|---|---|
| Deck & Bregu (2025), Southern Economic Journal | Lab experiment: calibrated puzzle task + innovation task with uncertain success | Participants with higher overconfidence abandoned attempts earlier than those with realistic self-assessments. Effect partially tempered by risk aversion. |
The question
If the members most likely to leave are the ones most sure they’ll succeed, what is the hype-based sales pitch buying you past the first six weeks?
People Also Ask
Does overconfidence always cause people to quit early?
Only when the member doesn’t yet know whether the goal is achievable for them. A returning lifter who’s watched their own body respond to training for two years has real evidence behind the confidence. In such a situation, confidence does roughly what motivational posters promise. The trouble appears in the zone before evidence exists, when a new member is running on belief alone.
How do you help overconfident new members stick around?
The research doesn’t hand you a retention tactic, but it does point at something earlier. The problem sits in the gap between what a new member was told to expect and what week six actually delivers. So expectations framed as certainties become the weak point in any onboarding flow. What a given operator chooses to do with that is up to them.
Isn’t this just about unrealistic expectations?
Partly. Unrealistic expectations are part of what breaks, but they aren’t the whole story. What Deck and Bregu added is a second layer, which is how the person reads their own failure. A member can lower the numbers they’re aiming for and still hold the deeper belief that they’re the sort of person this kind of program works for. That belief is the one that doesn’t survive an ordinary slow week six.
Confidence sells the membership. It can also be what cancels it.
References
Deck, C., & Bregu, K. (2025). The Discouraging Effect of Overconfidence. Southern Economic Journal, 92(3). https://doi.org/10.1002/soej.12788
Moore, D. A., & Healy, P. J. (2008). The trouble with overconfidence. Psychological Review, 115(2), 502-517.
If the members walking away from your gym sound like the one described above, the problem might sit further upstream than your retention email sequence.
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