Why behavioural science is the missing link in product growth

How behavioural science can drive user engagement and retention"

Most product teams focus on user experience (UX), conversion rates, and feature sets to drive growth. Yet, despite their best efforts, user engagement plateaus or churn rates remain stubbornly high. Why? Because products are designed for how we think people behave rather than how they actually behave.

Behavioural science provides a powerful framework to bridge this gap. By understanding the subconscious biases and decision-making patterns that influence user actions, you can craft experiences that guide users toward desired behaviours effortlessly.

Unlike traditional UX improvements, behavioural science dives deep into the psychology of decision-making. It explains why users abandon carts, why they procrastinate on account setup, and why they don’t engage with features they originally seemed excited about. When integrated correctly, behavioural science doesn’t just optimise conversions—it fundamentally reshapes user behaviour for long-term growth.

Behaviour: Identify the specific action you want users to take

Most companies focus on outcomes like retention, revenue, or engagement. But growth doesn’t happen in the abstract—it happens through specific user actions. Instead of vague goals like "increase engagement," pinpoint the exact behaviour you want to change.

The key is to define behaviour so specifically that it becomes measurable and actionable.

]Example: Peloton doesn’t just aim for "higher app engagement." Instead, they define success as users completing two 10-minute workouts with two different instructors in the first week.

Why does this matter? Because product teams that specify behaviours with this level of clarity can track and measure them effectively, making it easier to iterate and optimise user experiences.

Barriers: Remove friction ( Logistical and Cognitive)

Users abandon tasks not just because they are hard, but because they feel hard. Behavioral barriers fall into two categories:

• Logistical Barriers: These are obvious hurdles such as lengthy sign-up forms, unclear navigation, or requiring unnecessary information.

• Cognitive Barriers: These are mental and psychological frictions that prevent action. They include uncertainty, decision fatigue, loss aversion, and status quo bias.

Example: One Medical improved appointment bookings by 20% simply by recommending a doctor and limiting appointment choices to just a few immediate slots. This reduced decision fatigue and made scheduling feel effortless.

The lesson here is simple: make your product as easy to use as possible. If a user has to think too much before taking action, they will likely abandon the process.

Benefits: Highlight immediate wins, not just long-term value

Users prioritise now over later—a bias known as present bias. Products need to emphasise immediate benefits, not just long-term value.

Example: Asana leverages "completion bias" by making task completion visually satisfying with checkboxes and animations. This keeps users engaged, reinforcing productive behaviors.

This principle extends beyond gamification. Any product can find ways to make immediate benefits clearer and more tangible.

For example, consider a personal finance app. Instead of framing its value as "helping you save money for the future," it could highlight instant savings insights and daily spending patterns that help users make better decisions now.

Use defaults to drive the right behaviour

People are more likely to stick with the default option. This is why automatic enrollment in retirement savings dramatically increases participation rates.

Tactic: If you want users to enable security features, pre-select them during onboarding instead of requiring them to opt-in.

Example: Credit Karma increased recurring deposits by 18% by setting automatic transfers as the default option.

Another way to leverage defaults is in subscription models. Have you ever noticed how most SaaS platforms default users to an annual plan rather than a monthly one? This isn’t accidental—it capitalises on the status quo bias, reducing the likelihood of cancellation.

Inject friction—But only where It counts

While reducing friction is key to growth, adding friction can sometimes be just as effective in shaping behaviour.

Tactic: If you want to reduce harmful or impulsive actions, introduce a speed bump that forces users to reconsider.

Example: TikTok reduced misinformation sharing by 24% by adding a "confirmation prompt" before users could share flagged content. This simple nudge slowed users down and made them think before acting.

Friction can also be used positively to reinforce commitment. Duolingo, for instance, asks users to set daily learning goals, making them feel more committed to completing their language lessons.

Use social proof to encourage adoption

People are heavily influenced by what others are doing. If they see others engaging in a behavior, they’re more likely to follow suit.

Tactic: Show real-time usage stats or testimonials to reinforce trust and credibility.

Example: FinTech app Steady improved bank account sync rates by showcasing how many users had already completed the process, tapping into social proof to increase conversions.

Airbnb, for example, uses social proof by displaying how many people recently booked a property, creating a sense of urgency and validation that encourages others to book.

So how do you scale it?

For companies looking to integrate behavioural science systematically, here are some advanced approaches:

Conduct behavioural diagnoses

Map out every step a user takes to achieve the desired behavior. Identify drop-off points and determine if they stem from logistical or cognitive barriers.

Leverage behavioural experiments

A/B test different behavioural interventions—like subtle copy changes, different default settings, or various reward structures—to see what drives the most impact.

Align team Incentives with user behaviour

If your growth team is solely focused on increasing sign-ups, they might optimize for a short-term bump rather than sustainable user engagement. Instead, align incentives with behaviours that drive long-term retention.

Product growth isn’t just about better design, faster onboarding, or feature expansion—it’s about understanding people. By leveraging behavioural science, you can guide users toward desired behaviours, reduce friction, and enhance engagement, all while making their experience feel seamless and rewarding.

The best products don’t force behaviour change. They make the right action the easy and natural choice. And that’s the real secret to growth.