Broken promises, to other people and to ourselves, tend to get chalked up to a simple lack of willpower or follow-through. Two well-established, quite different bodies of psychological research suggest the real story is more specific, and less about willpower than it might seem.
The first comes from a 2006 meta-analysis by Tracy Webb and Paschal Sheeran, published in Psychological Bulletin. Rather than simply asking whether people with strong intentions behave differently from people with weak ones, which leaves open a lot of other explanations, the researchers specifically pooled 47 experimental studies that had directly manipulated people’s intentions, deliberately strengthening or weakening someone’s resolve to do something, and then measured what they actually did afterward. Even when the intervention succeeded in producing a large, genuine shift in intention, the resulting change in actual behavior was only small to moderate. In plain terms, meaningfully changing someone’s mind about doing something barely moves the needle on whether they go on to do it. This is one of the clearest pieces of experimental evidence behind what researchers call the intention-behavior gap, the well-documented tendency for even a real, sincere resolve to translate into surprisingly little actual follow-through.
A second study offers a plausible piece of the explanation, at least for promises made to ourselves specifically. In a 2011 study by Hal Hershfield, Daniel Goldstein, William Sharpe, Jesse Fox, Leo Yeykelis, Laura Carstensen, and Jeremy Bailenson, published in the Journal of Marketing Research, the researchers ran four separate studies, including one using immersive virtual reality, in which participants interacted with a realistic, age-progressed digital rendering of their own future self. People who had that experience, coming face to face with a believable image of who they’d eventually become, chose to set aside significantly more money for later, compared with people who only saw a current-day image of themselves. The researchers interpreted this as evidence that people commonly treat their future self almost like a stranger, someone psychologically distant enough that promises made on that person’s behalf, save more, exercise more, finish the project, don’t carry the same weight as promises made to someone who feels genuinely present and real.
Together, these two bodies of research suggest broken promises are less a simple willpower failure than a specific, identifiable mismatch. Webb and Sheeran’s research shows that resolve itself, even when it’s real and has been experimentally strengthened, is a surprisingly weak lever on actual behavior. Hershfield and colleagues’ research suggests one likely reason self-directed promises in particular are so easy to break: the future version of a person who will actually benefit from keeping the promise doesn’t feel fully real yet, making it easier to discount their interests in favor of whatever feels more urgent right now. Promises to other people carry an external presence keeping tabs; promises to a distant future self often don’t feel like they have anyone watching at all.
It’s worth being honest about what these studies don’t establish. Webb and Sheeran’s meta-analysis is built from short-term experimental studies measuring behavior over days or weeks, not months or years, so it speaks most directly to near-term follow-through rather than long-running life goals. Hershfield and colleagues’ studies focused specifically on financial savings behavior, so while the future self-continuity concept has been tested in other domains, the strongest, most direct evidence here is about money, and how well the exact mechanism generalizes to promises like exercise, relationships, or personal habits is a reasonable extrapolation rather than something this particular study measured directly.
Within those honest limits, the research supports a specific, more useful way of thinking about broken promises than simply blaming a lack of discipline. Resolve on its own appears to do surprisingly little work, and a meaningful share of the promises people break on their own behalf seem to fail specifically because the person meant to benefit, their own future self, doesn’t yet feel real enough to keep a promise to.
