# Uncertainty makes dopamine levels spike [[Dopamine triggers motivational salience]]: it encourages us to initiate behaviours which give us pleasure, and pleasure is associated to something that is beneficial to us. French fries, which have a high energy content, make us release more dopamine in anticipation than leafy greens. Dopamine is therefore a kind of alarm which signals to our brain how likely a behaviour is to be rewarded: it is the hormone of *anticipation of pleasure*. However, dopamine is released in largest quantity when the reward is *unexpected*: indeed, since the brain did not expect to receive pleasure, it signals all the more strongly to itself that the previous behaviour is a good one. That was once very important for our survival: if you randomly stumbled upon food on an unknown path, it was crucial to remember how to find it again. This is how most social networks work: a very simple action — scrolling on a smartphone with your thumb — can sometimes be rewarded with a funny story or a beautiful picture. Emphasis on *sometimes*, because this is what makes it so addictive. --- ## 📚 References - [[@whativelearnedScienceInternetAddiction2017|The Science of Internet Addiction & Willpower]] - [[@whativelearnedHowInternetRuins2016|How the Internet Ruins Productivity (by Design)]]