Med thumb postits

Sleep deprivation and work don’t go together. Caffeine and work do. In asserting these well-founded blanket statements, I’m referring to the job performance of individual employees defeated by exhaustion or jacked-up on coffee. However, the impact of sleep deprivation and caffeine on performance of group tasks, according to a new study published in Personality and Social Psychology Review, is a different story.

Previous research on alcohol illustrates the hairy relationship between individual and group performance. On an individual basis, people work better sober than drunk. But, assemble boozehounds and teetotalers into groups, and the sober sallies lose their edge.

Why? When group members’ individual judgment is impaired, and the group is aware, they alter their strategy for evaluating ideas. Members become less likely to entertain extreme suggestions and, in some cases, improve their coordinated efforts to compensate for clear deficiencies.

So, a sleepless night might severely affect my ability to come up with a clever headline. That doesn’t mean that sleep loss has a commensurate effect on a five-person team tasked with producing five clever headlines. When it comes to executing a task, a group of people isn’t necessarily the sum of its parts.

There isn’t much research on the issue  — we don’t yet understand how being tired or wired affects performance differently when we work solo and put our minds together. But, the current study authors touched on numerous factors relevant to designing groups in a way that protects against the ill-effects of sleep deprivation and capitalizes on caffeine buzzes.

Sleep-deprived workers, according to all sorts of studies and polls, tend to do less and lower-quality work, make more mistakes, incur more injuries and cause more accidents.

They also spend more time at work doing anything but work. The study calls it “loafing.” I call it clicking through the same slideshow of serial killers as children. (Seriously, it’s everywhere.)

Sleep deprivation is also linked to performance impairment on a range of cognitive and motor tasks. Working in groups, they believe, can both exacerbate and minimize the negative impact of sacrificed shut-eye. Here are a few issues to consider:


In many cases, slackers only slack more when they can disappear into a collective. But, certain measures appear to help, such as, publicizing group members’ contributions. People who can’t hide behind anonymity rise to the occasion.


Diversity of restfulness may hurt performance. If everyone’s low on sleep, people may feel inclined to pull one another’s weight, and motivation could spike. I think we call that empathy.

But, if just a few members are dragging, their alert coworkers may feel more annoyed than sympathetic, and show less mercy or willingness to do extra work.

Group Size

The negative impact of sleep deprivation, researchers argue, is amplified in larger groups. Why? Well, consider one thing sleep-deprived people do poorly: focus. If they can’t pitch in because they’re distracted, a larger group offers more distractions and, if everyone’s sleep deprived, more distracted people.

So, while a triumvirate of exhaustion may be more productive than three separate micro-sleeping employees, a 10-person group should divide and conquer.


Low-to-moderate amounts of the world’s most popular psychoactive substance is linked to better moods, sharper perception and improved performance on motor tasks. (Impact on higher-level cognitive thinking is somewhat more contested. We may perceive more benefits than actually exist.)

As with sleep deprivation, the relationship between caffeine and group performance hinges on varied factors, but amplifying caffeine enhancement is a different beast than minimizing impairment, and the optimal group structures differ accordingly.

Social Activity

The most pronounced effect of caffeine consumption is the mood-boost. Caffeinated people, therefore, work better in groups than alone in situations where being social is integral, or at least conducive, to success.