There's a lot of anecdotal evidence suggesting that email addiction leads to stress and unhappiness. Now, for the first time, researchers have tested this idea directly and found that, yep, there are probably positive psychological benefits to intentionally ignoring your email whenever possible. In a new study in Computers in Human Behavior, Kostadin Kushlev and Elizabeth Dunn of the University of British Columbia took a group of workers and, over the course of two weeks, assigned each to one of two conditions: One group was told to keep their email program closed, turn notifications off, and check their email only three times a day, and the other was told to leave notifications on and check their email as often as possible. After the first week, each group switched into the other condition, and each group was regularly surveyed about how often they were checking their email, how stressed they were, and how productive they felt.
Overall, "limiting the number of times people checked their email per day lessened tension during a particularly important activity and lowered overall day-to-day stress," the researchers write, and was associated with various other positive measures of psychological well-being. Those who checked their email a lot also didn't perceive themselves as any more productive than those who were on an email diet.
Now, some of these effects weren't all that big, but they were statistically significant. And this is still a promising study, in part because neither group group fully followed directions: While the baseline level of email checks per day was 15.5, the limited-email group checked email more often than they were supposed to (4.5 times a day instead of 3), and the unlimited-email group still checked theirs less than usual (12.5 times per day). In other words, it might be that if the groups had followed the directions better, there would have been a bigger gap between their email habits and therefore bigger differences in their stress levels (though there's no way to say for sure, of course).
Either way, this study, combined with a lot of prior research into things like the distractions imposed by task-switching, paint a pretty clear picture: Ceaselessly checking your email probably isn't making you more productive, and it probably is making you more stressed.