Do self-affirmations work? What the science says

In psychology, self-affirmation means reflecting on a value that matters to you (your family, your creativity, your kindness) and why it matters. It comes from a theory proposed by Claude Steele in the 1980s: we're all motivated to protect our sense of being a good, capable person. When something threatens that (a big presentation, a tough interview), reminding yourself of what you stand for elsewhere makes the threat feel less total.

The point isn't to tell yourself you'll be brilliant. It's to remember that one talk going badly can't touch the things that really define you. Oddly, that makes it easier to do the talk well.

Stress hormones. In a study at UCLA, 85 people either wrote about their most important value or about a value that mattered less to them. They then did a stressful lab task: giving a speech and doing mental arithmetic in front of evaluators. Those who had affirmed their values showed lower cortisol responses to the stress.

Well-being. A 2025 meta-analysis pooled 129 tests of self-affirmation exercises from published research, with 17,748 participants in total. The exercises led to small but significant improvements in how people saw themselves, in general and social well-being, and in negative symptoms like anxiety and low mood. The benefits were still there at follow-up, an average of about two weeks later.

You may know Amy Cuddy's TED talk on “power posing”. A 2010 study she co-authored reported that holding an expansive pose for two minutes raised testosterone, lowered cortisol and made people more willing to take risks.

Those hormone results didn't hold up. A 2015 replication with around 200 people (nearly five times the original sample) found no effect on hormones or risk-taking. In 2016 the original first author, Dana Carney, said publicly that she no longer believed the effects were real. What did replicate was smaller: people who held expansive poses reported feeling more powerful. Cuddy and colleagues have since argued that this effect on feelings is reliable.

The two ideas are different. Power posing works on the body. Self-affirmation works on what a stressful moment means to you. Standing tall won't hurt (good posture also helps your breathing), but for stress itself, values reflection has the stronger evidence.

Repeating positive statements about yourself isn't the same as self-affirmation. In one set of experiments, people with low self-esteem who repeated “I'm a lovable person” felt worseafterwards than those who didn't. A statement that clashes with how you see yourself can remind you of the gap.

Values reflection avoids that trap. You aren't claiming anything you don't believe. You're reminding yourself of something you already do.