Jeff Atwood over at CodingHorror recently posted a very interesting scientific basis for what we’ve all probably long suspected: email is addictive.

In the original article, there is a study on two lab rats. The first rat receives food after a fixed number of lever presses. The second rat receives food after a random number of presses. Fixed delivery vs variable delivery.

Intuition would say that the first setup is more addictive, as the rat with fixed delivery can predict and learn that pressing the lever results in food. As he wants more food, he will keep pressing.

But here’s the rub… as soon as the food stopped being dispensed, it was the second rat that kept pressing the lever for a very long time (whereas the first rat quickly gave up). It was addicted by the promise that food could arrive ‘any time now’.


Unfortunately for us, it’s the second rat who has the most email like experience… Replace ‘food’ with ‘new email’, and ‘lever’ with ‘opening/switching-to Gmail’, and you can most probably relate to the study. Conclusion? Email is a Variable Reinforcement Machine.

The heart of the issue is that, despite complaints about email overload, new email is rewarding. It can randomly deliver interesting news and opportunities from beloved contacts. The Variable Reinforcement Machine theory shows why the random nature of email makes checking for that reward so compulsive (even if the reward only rarely arrives).

The second addictive ‘hit’, the one that completes the cycle, is the reward of replying. It’s perhaps harks back to our school days – an opportunity to please teacher – or just the basic human gratification of helping someone else, that means we take pleasure in imaging how much joy our reply will bring the recipient. And so reply we do. And the act of replying brings in more email, and so the cycle repeats.

The real harm to all this checking is the damage to our attention. The inability to easily return our focus back to what we were doing before we checked. (In GTD terms, it’s a “context shift”, and that’s mentally expensive). That’s where the addiction truly hurts us.

The question that’s most interesting to our group is, do you control how often you check email? And if so, why + how? (Reasons not to limit checking would also be very interesting).


This was written by Andy Mitchell