2016-04-29 09:04:43
Scott Berinato
From the May 2016 Issue
The Research: Rebecca Spencer of UMass Amherst and her coresearchers, Uma
Karmarkar of Harvard Business School and Baba Shiv of Stanford Business School,
conducted a study in which they asked people to evaluate laptop cases for
potential purchase. First, subjects were given pros and cons of the products to
review. Some received the information late in the evening, shortly before they
went to sleep, and others in the morning, when they had their day ahead of
them. Twelve hours later, they were asked to choose a case and were also
surveyed about the products and their satisfaction with their selections. The
people who slept on their decision tended to feel worse about it.
The Challenge: Is the folk wisdom about thinking more clearly after a good
night s rest just a fable? Could it actually make your judgment worse?
Professor Spencer, defend your research.
Spencer: It was evident that the people who made a decision the same day felt
better about their choice than those who had slept on it. However, those who d
slept on it remembered more about the bags attributes. That surprised us. The
fact that they knew more about the products would suggest they d be happier
with their decisions, but they weren t.
HBR: Congratulations, your research invalidates age-old wisdom about making big
decisions.
I wouldn t say that. I wouldn t say there s no value to sleep with regard to
decision making. We know that when we sleep, the brain is doing some processing
that helps give us a clean slate. At a neurological level, information begins
to get cleared out of the short-term memory space and moved into long-term
memory space. So the proverbial belief that sleep gives you a fresh start is
true. It not only impacts how we take on new information but also appears to
have some surprising influence on past information.
How does it influence past information?
It wasn t just that people who slept on it remembered more information. When we
controlled for the number of positive and negative attributes in a follow-up
study, we saw that folks who slept on it were more likely to remember the
positive features and less likely to remember the negative ones.
Sleep makes us more positive?
That s what was so surprising. Many studies have shown that we remember more
negative things after sleeping. Then again, many of those studies were
comparing negative with neutral, not negative with positive. So in the context
of decision making, maybe sleep does make us focus on the good.
Why would people who remembered more good things be less satisfied with their
choices?
It might be more difficult to make a decision by comparing good things with
other good things than by comparing good with bad. I suspect that people are
conflicted because after the fact, they think about the good things they didn t
choose. It may be and this is something to study that when we asked them,
people felt they had made a poor decision, but over time they would come to
decide that it was good.
I d like to find a way to use your research to institute mandatory naps during
the workday.
We have done a lot with naps. Naps are beneficial to adults, just as they are
to little kids. What differs is that wakefulness is more detrimental to memory
and information processing in kids, so it appears that naps do more for them.
In this particular study, though, we eliminated people in the awake group who
had taken a nap, so I can t help you.
Choosing a laptop bag isn t exactly a high-stakes problem. When we talk about
sleeping on it, we re often wrestling with a big life choice or, say, a
decision on which people to fire. Maybe sleeping on it is better in those
situations?
It s true that our subjects were probably somewhat hesitant because they weren
t really in the market for laptop bags. What we want to do now is put people in
real-world situations say, catch them when they re actually shopping for a
camera online where there are actual needs and more information that could
affect decision quality. But the picture is more complicated when you get to
even bigger decisions, like laying off people. Maybe a decision occurs after
multiple nights of sleep. You re doing a lot of processing, moving a lot of
things to long-term memory. But if it s true that we tend to remember more of
the positive after sleeping, think about that firing decision. It becomes more
stressful because you re comparing positives. I can imagine how that might lead
to less satisfaction with the decision.
What if you added a deadline for the decision?
Well, stress impairs sleep. And lack of sleep has all kinds of negative
effects. The combination of deadline stress, decisions, and lack of sleep is a
bad one. We were looking at a less toxic combination in this study.
Some people wear insomnia like a badge of honor. I m guessing you d say getting
sleep is more important.
We know a lot about this now, and there s no question you need sleep. Pulling
an all-nighter will not help you. The tendency is to go as hard as you can and
brag about it, but research shows that you will be less able to attend to
detail and will react more slowly. You ll also respond more emotionally to
negative stimuli. Sleep keeps you on an even keel, and when you don t sleep,
things go bad fast. We can see this in fMRI studies. New information comes into
the hippocampus; if it s emotional, the amygdala gets involved, too, and may
trigger an overreaction. But sleep moves information out of the hippocampus so
that when you wake, you have a clean slate, and you experience new emotional
challenges with less baggage.
And what about all the talk of blue light from screens? Is that hurting our
sleep?
It s a little blown out of proportion. At sleep time, all light is bad; blue
light is a little worse. More important is the idea that sunlight is good. When
you re sitting in a windowless conference room during a meeting, melatonin is
trickling out of you. You re draining your stores, so at the end of the day,
they won t be there and you won t be sleepy. If you work in an office, you need
to expose yourself to more sunlight during the day.
I haven t decided whether or not we ll use this interview. I think I ll sleep
on it.
Great! When you wake up, you ll remember all the good parts.
A version of this article appeared in the May 2016 issue (pp.30 31) of Harvard
Business Review.
Scott Berinato is a senior editor at Harvard Business Review and the author of
Good Charts: The HBR Guide to Making Smarter, More Persuasive Data
Visualizations, forthcoming from Harvard Business Review Press and available
for pre-order now.