Most people can think of someone they’ve meant to thank properly but never quite got around to, holding back partly because it feels awkward or unnecessary. Two studies looking at what actually happens when people express gratitude suggest that hesitation is based on a real, measurable miscalculation, and that the impact of simply saying thank you tends to run much deeper than expected.
The clearest evidence comes from a 2018 study by Amit Kumar and Nicholas Epley, published in Psychological Science. Across three experiments, the researchers had participants write genuine letters of gratitude to real people in their lives, then predict how the recipient would react before actually sending the letter. Recipients, in turn, reported their real reactions once the letters arrived. Expressers consistently and significantly underestimated how positive and surprised recipients would feel, and separately overestimated how awkward the exchange would be for both sides. The gap wasn’t small or occasional, it showed up reliably across all three experiments, meaning people carry a systematic, predictable bias against expressing thanks, not just an occasional bout of shyness.
A second study helps show what’s actually lost when that hesitation wins out, using a real workplace setting rather than a one-time letter. In a 2010 study by Adam Grant and Francesca Gino, published in the Journal of Personality and Social Psychology, the researchers ran a field experiment with university fundraisers making solicitation calls. In one condition, a director personally thanked the fundraisers for their effort before they returned to work. In the following week, fundraisers who had been thanked made about 50 percent more solicitation calls than those who hadn’t received that acknowledgment. The researchers traced the effect specifically to increased feelings of social worth, a sense that their contribution genuinely mattered to someone else, rather than to a simple mood boost or increased confidence in their own ability.
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Together, these two studies suggest that expressing gratitude carries real, underappreciated weight on both ends of the exchange. Kumar and Epley’s research shows that the person doing the thanking consistently misjudges how the message will land, expecting awkwardness and getting genuine appreciation instead, a bias that likely keeps a lot of well-deserved thanks unsaid. Grant and Gino’s research shows what’s actually at stake in that hesitation: a brief, sincere thank you measurably changed how much effort people put into their work the following week, driven by a real shift in how valued they felt. Between the two, gratitude looks less like a small social nicety and more like a specific, underused lever, one that people avoid pulling mostly because they misjudge what will happen when they do.
It’s worth being honest about what these two studies don’t establish. Kumar and Epley’s research focused on the emotional reaction to gratitude letters specifically, so while the underestimation effect was strong and consistent, it doesn’t measure how that positive reaction translates into longer-term relationship change beyond the moment of receiving the letter. Grant and Gino’s research was conducted in a specific workplace context with a clear, measurable behavioral outcome, phone calls made, so the size of the effect may look different for less quantifiable forms of appreciation or in relationships outside of work.
Within those honest limits, the research offers a genuinely practical case for saying thank you more often than feels natural. The awkwardness people brace for turns out to be largely imagined, while the appreciation and sense of worth on the other end is real and, in at least one documented case, powerful enough to noticeably change someone’s behavior the following week.