It starts with a trigger, a prod that propels users into a four-step loop. Think of the e-mail notification you get when a friend tags you in a photo on Facebook. The trigger prompts you to take an action—say, to log in to Facebook. That leads to a reward: viewing the photo and reading the comments left by others. In the fourth step, you inject a personal stake by making an investment: say, leaving your own comment in the thread. This pattern kicks off a cycle that lodges behaviours in the basal ganglia, the part of the brain where automatic behaviours are stored and where, according to neuroscientists, they last a lifetime.
Yet technologists like Tristan Harris, a design ethicist who is also a product philosopher at Google, warn that growth hacking, taken to its extreme, can encourage sites and apps to escalate their use of persuasive design techniques with potentially unintended consequences for consumers. He compares online engagement maximisation efforts to the techniques some food companies have developed to hook consumers on a stew of fat, salt and sugar. “The ‘I don’t have enough willpower’ conversation misses the fact that there are 1,000 people on the other side of the screen whose job is to break down the self-regulation that you have,” said Mr. Harris.