Patterns
Assertiveness: standing up for yourself without attacking the other person
Assertiveness is the best-evidenced foundation for setting boundaries. Not passive, not dominant, but the middle ground: expressing your need clearly and respectfully.
6 min read
Editorial responsibility: Linda Bujitu · Published · Sources and editorial process
Of all the concepts around setting boundaries, assertiveness is the most researched. It is the most direct scientific foundation: the ability to express your needs, rights, and opinions directly and respectfully, without violating another person's rights.
Not passive, not dominant
Assertiveness is not aggression. Modern literature sees it as the middle ground between passivity and dominance. With passivity, your need disappears; with dominance, the other person's disappears. Assertive means: both are allowed to exist.
Assertive is the middle ground: your need counts, and so does theirs.
It can be learned
Assertiveness is described as a transdiagnostic, learnable skill. Assertiveness training typically involves behavioural rehearsal (practising in small steps), modelling (observing how it can be done), and cognitive restructuring (adjusting your thinking about the situation). The fact that it can be trained means that difficulty with boundaries is not a character flaw but a skill you can develop.
Honest about the nuance
Assertiveness training has a solid foundation, but no single technique is a magic solution. Popular slogans like 'no is a complete sentence' may hold true in situations of manipulation or abuse, but as a general rule they are too absolute. Being assertive requires timing and courage, not impulsive hardness.
From understanding to practising
Try it in a concrete situation
Continue with Lotte and Karim: explore responses, reflect on your own habits and choose one small next step.
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Frequently asked questions
What is the difference between assertive and aggressive?
Assertive means expressing your needs clearly and respectfully without violating the other person's rights. Aggressive comes at the other person's expense. Assertiveness is precisely the middle ground between self-erasure and dominance.
Can you learn assertiveness?
Yes. Assertiveness is a learnable skill. Practising in small steps, observing how others do it, and adjusting your thinking about the situation are evidence-based ways to develop it.
Sources
- Grenzen & Groei, internal research report (chapters 2 and 10)
- Yoshinaga, N., & Cooper, S. (2025). The four pathways of assertiveness. Frontiers in Psychology, 16, 1610807.
- Speed, B. C., Goldstein, B. L., & Goldfried, M. R. (2018). Assertiveness training: A forgotten evidence-based treatment. Clinical Psychology: Science and Practice, 25(1), e12216.
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