What strategy do you use when making complex decisions? Do you burn the midnight oil to carefully weigh the pros and cons of each alternative? Or do you take your mind off the decision and follow the age-old wisdom of "sleeping on it"?
“Careful consideration of all the options can be done by our unconscious mind”
Both decision-making methods have strengths and weaknesses, says Harvard Business School postdoctoral fellow Maarten Bos. Our conscious mind is pretty good at following rules, but our unconscious mind—our ability to "think without attention"—can handle a larger amount of information. Studying the unconscious mind offers exciting new avenues for research, including creativity, decision making, and sleep.
Research by Bos and his colleagues suggests that unconscious thought supports the kind of mental organization needed for making complex decisions. In addition, unconscious thought might be more dependable than conscious thought when we are low on energy. Preliminary research also indicates that using odor or sound cues during sleep might activate our unconscious mind and improve creativity and innovation.
Bos, a social psychologist, conducts his research at HBS, in close collaboration with Harvard Medical School. In addition to researching sleep, creativity, and decision making, he studies influence, persuasion, voice and facial categorization, and communication.
Martha Lagace: What do you mean by unconscious thought?
Maarten Bos: We define unconscious thought as a goal-dependent, deliberative process in the absence of conscious attention. Most people attribute a lot of their actions to a conscious process, but there are scores of processes that operate unconsciously. Getting dressed in the morning, for example, is largely an unconscious process. So is driving to work—many people get to work without entirely remembering how their drive was and what they saw on the road.
Lots of processes are automated and therefore very efficient. Our research shows thinking and deciding can also often be left successfully to the unconscious mind.
Here is an example of unconscious thought. Imagine you are listening to a song and can't remember the name of the artist. You try to think hard, but are still unable to come up with it. So you tell yourself, "I'll stop thinking about it, and it will come to me in a minute." This is fascinating. In fact, there is an automatic process that continues to work on your question in the back of your mind. We call that process "unconscious thought."
Unconscious thought can do more than just help you remember facts. It actually has the power to fuel the creative process. Have you ever found yourself struggling with the wording while writing a paper, but after taking time away from it, you're able to quickly find the right words? This is your unconscious mind at work.
While our conscious mind is focused on other matters, our unconscious mind can process the relevant information we need to make important decisions.
Q: As you highlight in an article about one of your research studies, "sleeping on it" is good folk wisdom for making decisions. Yet people often feel the need to carefully ponder all options and thus choose rationally. What does your research suggest about trying to navigate these two seemingly contradictory views?
A: Yes, there seems to be a discrepancy. People think, on the one hand, they should carefully consider all options before making a decision, but on the other hand, we say that we should 'sleep on our decisions.' My colleagues and I think both are true, and that careful consideration of all the options can be done by our unconscious mind.
Both conscious and unconscious thought have strengths and weaknesses. There are decisions where we believe conscious thought outperforms unconscious thought. For example, when a decision requires application of very strict, mathematical rules, we hypothesize that conscious thought is beneficial. But when it comes to integrating a large amount of information, we think unconscious thought, which gives rougher estimates, is more beneficial (see our article in Science for more information).
In recent work, we combined both conscious and unconscious thought and showed exactly that: Conscious thought was very good at selecting options that conformed to a certain decision rule. Since the study was about apartment selection, our participants had been told not to choose an apartment on the ground floor, for instance. It was unconscious thought that proved to be good at selecting options with the best aggregated information. (In the case of this study, participants were asked to choose an apartment with many positive, important attributes.) Yet it was the combination of both unconscious and conscious thought that produced the best results overall. It resulted in participants choosing options that were both compliant with the decision rule and had a high number of positive attributes.
Q: One way you and colleagues have tried to sort out the mechanisms of conscious or unconscious thought yielding better results in particular decisions has been by running experiments that alter blood glucose levels. Could you tell us more about that?
A: We ran experiments where we manipulated the amount of sugar people ingested in a three-hour time period. We showed that while giving people a drink with sugar helps conscious thought—not a strange finding, considering our brain is fueled by glucose—surprisingly, unconscious thought performs better when people receive a drink without sugar in it. It seems that unconscious thought is not as dependent on glucose as conscious thought.
Other research conducted by [Mareike] Wieth and [Rose] Zacks has shown people are very good at making intuitive decisions at times when they are not at their best according to their circadian clock. In this research participants showed greater insight and creative problem-solving performance during nonoptimal times of day compared to optimal times of day. It seems that conscious thought sometimes gets in the way of making good decisions.
Q: You and your colleagues also study sleep and creative performance, as you write in an article in the Journal of Sleep Research. You take the interesting tack of studying odor. Why?
A: We used odor as a cue to reactivate thoughts about a task. This cue has the potential to increase information processing during sleep—a finding with powerful practical applications.
First, the cue is paired with a task, then the cue is repeated during sleep. To give an example: Imagine that you are reading materials for an important meeting right before you go to sleep. While you are reading, a cue is produced—either a smell is dispersed in the room or a distinct sound is played. Then during the night, that same cue is produced. The cue reactivates the reading you did before going to sleep and improves your memory of the information. This strategy could potentially act as a study aid for students and professionals alike.
So far, though, we have only found results for creativity. People were given instructions for a creativity task, paired with a cue, before they went to sleep. Those participants who were given the same cue at night were more creative the next morning.
Q: What are you working on next?
A: These are very exciting times. There is so much to do! One question we are investigating is which sleep phases are most sensitive to these conditioned cues I just mentioned. Replaying a cue all night might make the cue less effective. (Imagine putting on cologne in the morning. After about 20 seconds you don't smell it anymore because you've gotten used to it.) We don't know if this replaying affects the effectiveness of the cue. We also don't know if people get used to sounds or music in the same way. If we find out in which sleep phase these cues are most effective, then we may learn more about memory processing during sleep. We also need to do more research to find out if sleep quality is adversely affected by the cues, but no results so far indicate that sleep is disrupted.
“We could tap into the vast potential of the unconscious, while we're comfortably sleeping in our beds”
Another route we're investigating is whether this cue-activated boost works for decision making like it did for creativity. Creativity can be a very divergent process, while decision making is a more convergent process. We don't know for sure if sleep works the same, or as beneficially, for both of these processes.
I'm also working on various other lines of research that are less related to sleep. But whether it's sleep research (with Harvard Medical School's Robert Stickgold and Harvard Kennedy School's Todd Rogers, HBS PhDOB'08), influence and persuasion research (with my main collaborator at HBS, professor Amy Cuddy), voice analysis research (with Amy Cuddy and Cornell's Tanzeem Choudhury and her student Mashfiqui Rabbi), decision-making research (with Radboud University's Ap Dijksterhuis and Kellogg's Loran Nordgren), creativity research (with Harvard Psychology's Adrian Ward and Catalyst's Anna Beninger), or body posture research (with Amy Cuddy and MIT's Ehsan Hoque), almost all the research I do is about the unconscious and cognitive performance, and I really think it's fascinating stuff.
I'll leave you with this. We sleep about a quarter to a third of our lives. Imagine how powerful it would be if we could make that time more useful? If the reactivation works the way we think it does—and the way our data show it works—then the applications are endless. We could tap into the vast potential of the unconscious, while we're comfortably sleeping in our beds.