Caffeine makes people more positive by making them more alert
Ohio State University
Researchers found that people gave more positive reviews for
their group's performance on a task -- and their own contribution -- if they
drank caffeinated coffee beforehand.
A second study showed that people talked more in a group setting
under the influence of caffeinated coffee -- but they also were more on-topic
than those who drank decaf.
Coffee seems to work its magic in teams by making people more
alert, said Amit Singh, co-author of the study and a doctoral student in
marketing at The Ohio State University's Fisher College of Business.
"We found that increased alertness was what led to the positive results for team performance," Singh said.
"Not surprisingly, people who drank caffeinated coffee
tended to be more alert."
Singh conducted the study with Vasu Unnava and H. Rao Unnava,
both formerly at Ohio State and now with the Graduate School of Management at
the University of California, Davis. The study appears online in the Journal
of Psychopharmacology.
While many studies have looked at how caffeine affects
individual performance, this is the first to examine the impact it has on
teams, Singh said.
The first study involved 72 undergraduate students who said they
were coffee drinkers. They were instructed not to drink coffee before the
experiment.
Half of them first participated in what they were told was a
coffee-tasting task. They were split into groups of five.
After drinking a cup of coffee and rating its flavor, they were given 30 minutes of filler tasks to give the caffeine a chance to kick in. The other half of the participants did the coffee tasting at the end of the experiment.
After drinking a cup of coffee and rating its flavor, they were given 30 minutes of filler tasks to give the caffeine a chance to kick in. The other half of the participants did the coffee tasting at the end of the experiment.
Each group then read about and were asked to discuss a
controversial topic -- the Occupy movement, a liberal movement that highlighted
social and economic inequality. After a 15-minute discussion, group members
evaluated themselves and the other group members.
Results showed that those who drank the coffee before the
discussion rated themselves and their fellow team members more positively than
did those who drank coffee after the discussion, Singh said.
The second study was similar, except that 61 students all drank
coffee at the beginning of the study. However, half drank decaf and the others
drank caffeinated brew.
Those who drank caffeinated coffee rated themselves and their
fellow group members more positively than those who drank decaf.
It had to do with alertness.
All participants rated how alert they felt at the end of the
study, and those who drank the caffeinated coffee rated themselves as more
alert than the others.
A key finding was that people who rated themselves as more alert
-- whether they drank caffeinated coffee or not -- also tended to give higher
marks to themselves and their fellow group members.
This suggests that any intervention that increases alertness (such as exercise) may also produce similar results, which the authors propose in the paper as a future research topic.
"We suspect that when people are more alert they see
themselves and the other group members contributing more, and that gives them a
more positive attitude," Singh said.
But the caffeine does more than just increase good feelings. The
researchers did an analysis of the group discussion in the second study, rating
how much each group member talked and stayed on topic.
Results showed that people tended to talk more after drinking
caffeine, but they also tended to stay more on topic.
"They're talking about more relevant things after drinking
caffeinated coffee," he said.
One might think that if people are talking more about a
controversial topic like the Occupy movement, that may cause friction in the
group. But that's not what the study suggests.
People who drank caffeinated coffee were more likely than those
who drank decaf to say they would be willing to work with their group again.
"Even though they are talking more, agreeing and
disagreeing, they still want to work with them again," Singh said.
"Coffee didn't seem to make group discussions too
uncomfortable and disagreeable."