How product developers hook users

What distinguishes the Hook Model from a plain vanilla feedback loop is the Hook’s ability to create a craving.

Feedback loops are all around us, but predictable ones don’t create desire. The unsurprising response of your fridge light turning on when you open the door doesn’t drive you to keep opening it again and again. However, add some variability to the mix—suppose a different treat magically appears in your fridge every time you open it—and voilà, intrigue is created.

Variable rewards are one of the most powerful tools companies implement to hook users….

Research shows that levels of the neurotransmitter dopamine surge when the brain is expecting a reward.

Introducing variability multiplies the effect, creating a focused state, which suppresses the areas of the brain associated with judgment and reason while activating the parts associated with wanting and desire.

Although classic examples include slot machines and lotteries, variable rewards are prevalent in many other habit-forming products.

Source: Hooked: How to Build Habit-Forming Products by Nir Eyal