Understanding Assertiveness

Assertiveness is the ability to express your opinions, needs and boundaries clearly and directly, while respecting those of others. The word comes from to assert (to affirm). The concept emerged in the 1940s–1950s with the psychologist Andrew Salter (Conditioned Reflex Therapy, 1949), then was popularized by Joseph Wolpe, who used the term "assertive behavior" in his work on anxiety.

Assertiveness is neither coldness nor polite aggression: it's a balance between respect for oneself and respect for others. An assertive person defends their viewpoint without attacking, and listens to the other's without erasing themselves.

"You have the right to express your feelings, opinions and needs — and to take responsibility for them." — a central principle of self-assertion, formulated by Manuel J. Smith (When I Say No, I Feel Guilty, 1975).

The four communication styles

Faced with tension, we spontaneously adopt one of four styles. Recognizing them is the first step toward consciously choosing assertiveness.

The passive style avoids immediate conflict but accumulates resentment. The aggressive style sometimes wins in the short term but destroys the relationship. The passive-aggressive style — sarcasm, deliberate lateness, a "yes" followed by a factual no — is the most toxic because it hides the disagreement. Only the assertive style is sustainable.

quadrantChart
    title Styles by respect for self and others
    x-axis "Low respect for others" --> "High respect for others"
    y-axis "Low respect for self" --> "High respect for self"
    quadrant-1 "Assertive"
    quadrant-2 "Aggressive"
    quadrant-3 "Passive-aggressive"
    quadrant-4 "Passive"

What to say / what not to say

Situation: a colleague again asks you to finish their report.

• Passive: "Uh… okay, I'll try to find the time." (then resentment)
• Aggressive: "Figure it out yourself, not my problem, you should organize better."
• Passive-aggressive: "Yeah, yeah, no problem…" (then the report is never done)
• Assertive: "I understand you're under pressure. Right now, I can't take your report on top of mine. I can show you how I structured mine if that helps."

The assertive version says no to the request without saying no to the person: it acknowledges the other, sets a clear boundary and offers an alternative.

Assertiveness and self-esteem: a virtuous cycle

Assertiveness is not just a communication technique; it's tied to self-esteem. Each time we assert ourselves with respect, we send our own brain the message "my needs are legitimate," which builds confidence. Conversely, each passive self-erasure confirms the belief "I don't matter." Practicing assertiveness therefore acts both on the relationship and on the relationship with oneself.

A behavior, not a personality trait

A key point: assertiveness is a situational behavior, not a fixed trait. One can be assertive at work and passive at home, or vice versa. No one is 100% assertive all the time. This changes everything: since it's a behavior, it can be learned and trained, context by context.

Practical exercise

Think back to three recent situations where you didn't express what you thought. For each, identify the style adopted (passive, aggressive, passive-aggressive) and write what an assertive response could have been. Note the emotion you felt afterward in each case.

Summary

Assertiveness is the ability to express oneself with respect for self and others, distinct from passive, aggressive and passive-aggressive styles. Theorized by Salter and Wolpe, popularized by Manuel Smith, it is a situational behavior that can be learned, and maintains a virtuous cycle with self-esteem.