We are attracted to devices that track our activities

Global sales of wearable devices that track daily activity and allow users to get notifications will reach $1bn by 2022.

One neuroscientist says part of the attraction for users is the way many of these apps 'reward' users. When you see your step count or sleep hours in an app, it creates a feedback loop where you experience an immediate reward. Progress badges can become more important than the outcome itself.