Here’s a word we all use daily: behaviour.

But have you ever stopped to ask what it really means?

In behavioural design, clarity is everything. If you don’t nail down what behaviour is—and what it isn’t—you risk making fuzzy decisions, creating vague solutions, and missing opportunities to influence.

Let’s get crystal clear: what behaviour is, how it differs from related concepts, and why this clarity matters.

What is Behaviour?

Behaviour is action. It’s what people do, whether consciously or automatically.

• Choosing what to wear? Behaviour.

• Jumping at a loud noise? Behaviour.
  

Every decision, reaction, or movement—intentional or instinctive—counts. Behaviour is what happens when thought meets action, or when instinct bypasses thought altogether.

Behaviour vs. What It’s Not

To design for behaviour, you need to know what it isn’t. Here’s where most people trip up:

Behaviour vs. Habits

• Habits are behaviours repeated so often they become automatic.

• Example: Brushing your teeth every morning isn’t a decision anymore—it’s a habit.
  

Habits are a type of behaviour, but not all behaviours are habits.

Behaviour vs. Attitudes

• Attitudes are what people think or feel. Behaviour is what they do.

• Example: Liking jogging (attitude) doesn’t mean you actually jog (behaviour).
  

Your attitude may shape your behaviour, but they aren’t the same thing.

Behaviour vs. Mood

• Mood is your emotional state—how you’re feeling at any given moment.

• Example: Feeling sad (mood) might make you sit quietly (behaviour).

Moods influence behaviour, but they’re not behaviours themselves.

Behaviour vs. Influence

• Influence is the external force that nudges you toward a behaviour.

• Example: An advert that convinces you to buy something is influence. The buying itself? That’s behaviour.

Influence is about what drives behaviour, not the action itself.

Behaviour in Practice

When we talk about behaviour in fields like behavioural design, psychology, or user experience, we’re zooming in on actionable, observable behaviours—the things people do that can be influenced or changed.

Why? Because behaviour is the thing that drives results. It’s what turns theory into outcomes.

Why This Definition Matters

If you misdefine behaviour, you’re designing blind:

• You’ll tackle the wrong problems.

• Create interventions that miss the mark.

• And waste opportunities to make meaningful impact.
  

Getting it right means you can observe, analyse, and guide behaviour with confidence. You’ll know the difference between what you can influence and what you can’t, and focus your efforts where they’ll make the biggest difference.

Spotting Behaviour in Action

Here’s the trick: as projects or conversations evolve, the meaning of “behaviour” can shift without anyone noticing. Suddenly, people are talking about mood, habits, or attitudes instead.

Your job? Bring it back to action.

Ask yourself:

• What’s the behaviour we’re trying to change?

• How does it happen?

• What drives it?

The Bottom Line

Behaviour is what people do. Nothing more, nothing less. Get this clear, and you’re armed to design solutions that actually work.

Misunderstand it, and you’ll chase the wrong problems, craft vague ideas, and miss the chance to create real change.

So next time someone talks about “behaviour,” stop. Define it. Clarify it. Then build solutions that matter.

That’s how you win with behavioural design.

Author

Catch-up

Lauren Alys Kelly

Founder

Lauren makes behaviour behave. As the founder of BehaviourKit and Alterkind, she’s helped teams like Meta and Microsoft tackle behaviour challenges with clarity and impact.