Why are some digital products so addictive?

What makes some websites or apps so addictive? I’m sure it’s something a lot of us wonder – I know I have. Nir Eyal’s ‘Hook’ theory attempts to provide an answer, with a four-step cycle of habit-forming behaviour for products.


1. Trigger

Habit-forming products first use external triggers (such as an app icon, an email) to alert users to their existence. Users begin to associate these with behaviours or emotions. We form habits when we are triggered to use the product if we feel a certain way or are doing something in particular – say, someone might feel like checking Twitter when they are feeling lonely.

2. Action

This step requires motivation and the actual ability to take action, as a response to the trigger. For example, tapping on a game app icon because you have spare time to play it on your commute home from work.

3. Variable reward

According to Eyal, unpredictability of rewards increases user anticipation and amplifies the feeling of reward. For example, when using Facebook, you upload an image, but you’re not sure how many likes it will generate.

4. Investment

This is the point where the user has to give something: time, data, effort or money. Through this investment, the user becomes more attached. Eyal provides the example of Pinterest. Re-pinning images and following other pinners enhances a user’s experience, and thus their ties to the service.

Whilst it’s hard to present a one-size-fits-all theory for human behaviours, Eyal’s cycle is a pretty interesting concept. You can read a bit more about the ‘Hook’ theory here.

(I’d also recommend checking out the rest of his blog for some interesting reads).

– Lucy