Assertiveness gets talked about as a personality trait, something a person either has or doesn’t. A specific clinical trial suggests something more useful: it behaves like a skill, one that can be deliberately trained, with real effects that show up well beyond just seeming more confident.
The clearest evidence comes from a 2023 study by Tobias Hagberg, Per Manhem, Martina Oscarsson, Fanny Michel, Gerhard Andersson, and Per Carlbring, published in Internet Interventions. The researchers randomly assigned 210 adults to one of three groups: an eight-week, therapist-guided online assertiveness training program, an unguided self-help version of the same program, or a wait-list control group that received no intervention. Compared with the wait-list group, both training conditions produced large gains in self-rated assertive behavior, and the gains were still present a full year after treatment ended, not just immediately afterward. The training also measurably reduced social anxiety symptoms and improved participants’ general sense of wellbeing. Between 19 and 36 percent of participants, depending on the specific measure, showed what the researchers classified as reliable clinical recovery. Assertiveness, in other words, responded to structured practice the way a learnable skill does, not the way a fixed trait would.
A second, very different study helps explain why building that skill isn’t always a simple, universally rewarded improvement. In a 2016 meta-analysis by Melissa Williams and Larissa Tiedens, published in Psychological Bulletin, the researchers pooled data from dozens of studies, 63 examining likability and 20 examining hireability, looking at how assertive or dominant behavior gets received differently depending on gender. Explicit assertiveness, direct demands, clearly stated opinions, pushing back openly, reliably hurt women’s likability compared with men displaying the identical behavior, and hurt women’s hireability by a larger margin still. Notably, competence ratings weren’t affected by gender at all, people didn’t see assertive women as less capable, just less likable and less hireable. And the penalty was specific to explicit assertiveness: the same underlying dominance expressed implicitly, through posture, eye contact, or tone, carried no measurable penalty for women at all.
Together, these two studies sketch a more complete, more honest picture of what building assertiveness actually involves. Hagberg and colleagues’ trial shows assertiveness is a genuinely trainable skill with real, durable benefits for anxiety and wellbeing, not something a person is simply born with or without. Williams and Tiedens’s meta-analysis shows that practicing and expressing that skill doesn’t land the same way for everyone, women who express assertiveness explicitly and directly can face a real social penalty that men expressing the identical behavior generally don’t. The skill itself is learnable and beneficial. How it gets received once someone actually uses it depends on more than just how well they’ve learned it.
It’s worth being honest about what these two studies don’t establish. Hagberg and colleagues’ trial measured self-reported assertive behavior and wellbeing rather than independently observed changes in real-world interactions, so it captures how participants perceived their own growth rather than how outside observers might rate it. Williams and Tiedens’s meta-analysis pools studies that vary in method, context, and time period, and while the pattern held up consistently across a large pool of research, meta-analytic effect sizes describe averages across many different situations rather than predicting exactly what will happen in any single specific interaction.
Within those honest limits, the research supports a more complete version of what “the art of being assertive” actually requires than simply learning to speak up. It’s a skill that responds well to real, structured practice, with genuine payoffs for anxiety and wellbeing. But building it well also seems to mean being aware that how it lands can depend on more than the words used, and that the same direct honesty doesn’t always get received the same way for everyone.
