SHANKAR VEDANTAM, HOST: This is HIDDEN BRAIN. I'm Shankar Vedantam.(SOUNDBITE OF SNORING)VEDANTAM: Maybe your mornings sound like this.(SOUNDBITE OF PHONE ALARM)VEDANTAM: You wake up to your alarm ringing. You turn it off and bring your phone back to bed with you. You scroll through email and social media, squinting through one eye to see what you've got to get done and what's happening in the news. When you finally get up and start getting ready, maybe you have some music going.(SOUNDBITE OF MUSIC)VEDANTAM: Or your favorite TV channel.(SOUNDBITE OF NEWS CHANNEL)UNIDENTIFIED REPORTER: And we continue to follow that breaking news in south Charlotte...VEDANTAM: Many of us are voracious consumers of information, and we're always looking for new ways to take in even more.(SOUNDBITE OF ARCHIVED RECORDING)UNIDENTIFIED WOMAN #1: Alexa, what's the weather today?ALEXA: In Charlotte, N.C., it's 63 degrees with mostly sunny skies.VEDANTAM: But even as we savor good news about the weather or the stock market or weekend plans, we're also regularly confronted by stuff that's unpleasant.(SOUNDBITE OF ARCHIVED RECORDING)SIMULATED VOICE: To listen to your unread voicemails, press one.VEDANTAM: Unpleasant information creates a paradox for the brain. This kind of information is often very important.(SOUNDBITE OF ARCHIVED RECORDING)SIMULATED VOICE: First message.UNIDENTIFIED MAN #1: This is the principal calling from your son's school. Please contact us so we can arrange a time to discuss your son's behavior.VEDANTAM: But this kind of information also produces psychic pain. And one of the oldest rules in the brain is to avoid things that are painful.(SOUNDBITE OF ARCHIVED RECORDING)SIMULATED VOICE: Second message.UNIDENTIFIED WOMAN #2: This is the doctor's office. Your test results have come in. Pleas call us back immediately.VEDANTAM: The tension between what we rationally know to be important and what we emotionally experience as painful is the subject of our episode today.(SOUNDBITE OF ARCHIVED RECORDING)SIMULATED VOICE: Third message.UNIDENTIFIED WOMAN #3: Hey, just call me back as soon as you get this. I've - OK, I saw your wife kissing somebody. Sorry. Just give me a call.VEDANTAM: It's about why we sometimes...(SOUNDBITE OF ARCHIVED RECORDING)SIMULATED VOICE: Message deleted. Message deleted. Message deleted.VEDANTAM: ...Shut it all out. Why we look away and the consequences of doing so, this week on HIDDEN BRAIN.(SOUNDBITE OF MUSIC)VEDANTAM: There's an old theory in economics about information. It goes like this. You should always be willing to hear information about your finances or your health. For example...UNIDENTIFIED WOMAN #4: Hey, Antonio (ph), help yourself to anything in the fridge. But heads up, sniff the milk first. I think it's getting close to the expiration date.VEDANTAM: Maybe this information is useful. Maybe it's not.ANTONIO: Oh, I'm fine. I'm actually lactose intolerant.VEDANTAM: No matter how you feel about the information, there's one thing you should never do.JOSHUA TASOFF: A person should never avoid information because information can never hurt a decision.VEDANTAM: This is Josh Tasoff.TASOFF: I'm a assistant professor of economics at Claremont Graduate University.VEDANTAM: Josh says less is never more when it comes to information. We always should want to know if our 401(k) is about to take a nosedive or if we're at risk of contracting a disease. But here's the thing. Humans aren't always rational. And when it comes to information...TASOFF: Information can be anxiety-provoking. It can be depressing.VEDANTAM: What do we do when something makes us sad or depressed? We turn away from it. When the thing that's depressing is information, we say, I don't want to hear about it. Social scientists call this behavior information aversion. More commonly, it's called the ostrich effect. The term comes not from birds, but investors.TASOFF: So when the stock market goes down, people check their portfolio less frequently than when the stock market is going up.VEDANTAM: And why would that be?TASOFF: Well, the interpretation is that the information causes sort of an immediate pain just from hearing it, right? People are anticipating sort of their future losses. Of course, they don't actually have any losses yet. But they're anticipating those future losses, and that causes an emotional pains - obtaining that information.VEDANTAM: Information aversion is one of many, many domains where human behavior seems to deviate from the models of economists. Instead of doing the rational thing, learning as much as possible about something, many of us do the opposite. We stick our heads in the sand. And this is true for more than just financial information. A couple of months ago, we asked HIDDEN BRAIN listeners to call in and tell us about their news consumption.ANNIE: Hi, Annie (ph) here.NANCY WALTER: Hello, my name is Nancy Walter (ph).JASON FLAKES: Hi, Shankar. This is Jason Flakes (ph).VEDANTAM: Jason, Nancy and Annie are all addicted to the news.WALTER: My husband and I are news junkies.FLAKES: I love listening to the news every day.ANNIE: Checking it every few hours.VEDANTAM: Or at least, they were addicted to the news until Donald Trump caught them by surprise and won the 2016 presidential election.WALTER: I hadn't anticipated Donald Trump winning. So I went on a complete news blackout.FLAKES: Just because of the frustration that I was feeling.ANNIE: And actually had a lot of anxiety because of it. I have dramatically changed the way I read the news following the election.VEDANTAM: These listeners had their fingers on the pulse of political news before the election, when Hillary Clinton appeared to be poised for victory. But in the days and weeks after Trump's surprising win, Jason, Nancy and Annie began to avoid the news. It was like the investors who stare lovingly at their portfolios when the stock market's on the rise but avoid looking whenever the market dips. Headlines about the Trump administration stressed these listeners out. It caused them pain. And that's a key marker of information aversion.Now, there are times when people avoid information when it's simply too much to digest. Let's say you're studying for a big test. And after hours and hours of reading, you close your textbooks and take a break. This is information overload. You're burnt out from taking in so much stuff. With information aversion, the driver isn't that there's too much information. It's that the information is unpleasant. If you were to tell these people about pleasant things, they'd be glad to listen all day.TASOFF: People want information - want more information about happier future experiences than less happy future experiences.VEDANTAM: Josh wanted to see how much people prefer happy information to unpleasant information. He wanted to test that age-old theory, you should always be willing to hear information about your finances or your health. So he teamed up with a colleague.ANANDA GANGULY: I'm Ananda Ganguly. I am at Claremont McKenna College.VEDANTAM: And he asked participants to come in and sit at a desk for 20 minutes.TASOFF: And posted in - at their cubicle in front of them were two envelopes - one labeled big and one labeled small.VEDANTAM: They told the volunteers that there was a 10 percent chance the envelopes were filled with cash.TASOFF: But if the big envelope contains money, it contains $100. If the small envelope contains money, it contains $10.VEDANTAM: The volunteers would get to open the envelopes at the end of 20 minutes and pocket the contents. Now, if 20 minutes was too long to wait, Josh and Ananda said the volunteers could pay money to open one of the envelopes immediately.GANGULY: 83.4 percent paid money to affect the timing.VEDANTAM: Did you actually physically observe the volunteers? Did you notice anything as they were dealing with this? Could you actually see the dilemma on their faces?GANGULY: Yeah. They were in the computer - they were in a computer lab and doing this. And absolutely, I mean, there was - it was almost like in a casino. But immediately, they would start tearing the envelopes open and immediately very excited about it. And, you know, F-words would fly.VEDANTAM: (Laughter) And would F-words fly once they'd open the envelopes or before?GANGULY: After they opened the envelopes (laughter) - it's the disappointment or the surprise.VEDANTAM: Here's the trick in the experiment. Remember that there were two envelopes - one big, one small. Big envelopes carry the potential of a big sum of money. Small envelopes carry the potential of a small sum of money. You can guess which ones the volunteers wanted to open.TASOFF: What we find is that people are twice as likely to open up the big envelope over the small envelope. The interpretation is that winning $100 is a lot more happy and a lot more exciting than winning $10. And so people's demand for that information, even though it's completely useless in their decision-making, is much higher.VEDANTAM: I'm not sure I fully followed that. Walk me through that again.TASOFF: Well, the information here is completely useless for making any decisions. So no matter what, they're going to get this money or not get the money, right? But they're just going to sit there for 20 minutes. And so receiving this information, unlike, you know, other decisions in our life, like - and you could think in our daily life, if you're going to get a raise or anything like this - that information can be very useful because it'll help you improve your purchase decisions right now in the present.But here, they're basically stuck sitting in the lab in a seat. And so receiving this information 20 minutes earlier is completely useless. They can't use it to make - improve any decisions in that short interim period.VEDANTAM: Even if receiving the information earlier was useless, lots of volunteers were perfectly willing to pay to find out what was inside the envelope sooner. The bigger the potential good news, the more likely volunteers were to pay. The studies show that people are hungry for information when information is pleasant. Now, there's one important detail we haven't told you yet. The amount of volunteers had to pay wasn't very much - just 50 cents to open an envelope. Since the big envelope could hold as much as $100, you might say that paying 50 cents was a trivial cost.TASOFF: We wanted to look at something that had greater real-world stakes.VEDANTAM: We know people want pleasant information. But are they willing to pay to avoid unpleasant news, like information about a disease? Josh and Ananda decided to find out. They thought about the health concerns you might see on a college campus.TASOFF: The sample that we have access to are college undergrads, right? And so we could do something like a cancer test, but I don't think college undergrads are terribly concerned about that. I think what college undergrads tend to be typically concerned about is STDs.VEDANTAM: STDs - sexually transmitted diseases. One of the most stigmatized and common diseases on college campuses is herpes. It's caused by the herpes simplex virus, or HSV.GANGULY: We chose HSV because the prevalence - the rate of prevalence of HSV in this population is rather high. I mean, rough numbers are around 50 percent. Chances are every other person has it. So they would have it. And then the other attractive thing of - about HSV for us is it had this kind of two levels, kind of parallel to our $10 - $10 and $100 thing.TASOFF: There's herpes simplex virus 1 and herpes simplex virus 2. Herpes simplex virus 1 is typically associated with cold sores. And herpes simplex virus 2 is typically associated with genital herpes.GANGULY: HSV-1, that's the oral herpes, is less - considered to be less severe or less stigmatic or whatever in the population.VEDANTAM: Ananda and Josh asked college students to come back to their lab. This time, volunteers were asked to sit through a webinar about herpes.GANGULY: We actually gave them photographs of sores on the lips and photographs of sores on male and female genitalia with a discussion of HSV-1 and HSV-2.VEDANTAM: And these pictures were graphic?GANGULY: These pictures were very graphic. In fact, we don't know that we'll be able - we want to put it in the paper. They were completely clinical graphic.VEDANTAM: Since Josh and Ananda knew that some people avoid getting tested for herpes because they don't want to deal with a blood test, volunteers were told they had to have their blood drawn in order to stay in the study. The researchers told volunteers they could have the blood tested for free for both kinds of herpes. Volunteers were assured confidentiality.GANGULY: They were allowed to call into the lab with their initials and four randomly selected numbers of their own choice. Even the doctor would not know who they were.VEDANTAM: So to recap, students were given graphic information about two forms of herpes. The researchers then proceeded to eliminate all the usual reasons someone might not want to get tested for the sexually transmitted disease. It was mandatory for the volunteers to get their blood drawn. The test was free, and the results would be obtained confidentially.Would volunteers elect to find out if they had herpes, or would they choose to bury their heads in the sand? To test for information aversion, the researchers told the volunteers that they would have to pay $10 to not get their blood tested. A significant number of volunteers elected to pay this money. And just as the researchers had expected, volunteers were more likely to pay money to avoid getting highly unpleasant information about genital herpes than the less unpleasant information about oral herpes.Tell me about those people. So they just - did that happen in front of them? Or how did that happen?GANGULY: So the phlebotomist drew the blood. And we said, OK, so this was your choice. You had chosen not to be tested. So now this blood would be discarded. Would you please drop it down the sink and wash it up?VEDANTAM: And they did.GANGULY: They did. They would drop the tube into the sink and turn on the faucet, and it would go.VEDANTAM: I mean, at some level, that has to be a little bit disturbing, right? - the idea that you're drawing blood and throwing it down the sink.GANGULY: Yes, absolutely. And that's kind of the point here though. So they are going to have the blood drawn. So you'd rather pay money, waste that blood, than know what your test results were.VEDANTAM: Did any of the students give you verbal feedback about what happened and their impressions of it? Did any of them explain why they declined to be tested? I mean, they obviously must have thought about what the implications were as they made the choice.TASOFF: Oh, yeah, so as - yeah, we actually asked them, what was their motivation? 85.7 percent, the most common explanation, was because, quote, "it will cause me unnecessary stress or anxiety if I test positive."VEDANTAM: It's worth pointing out that lots of students elected to receive the information about whether they had herpes. In fact, a majority of students elected to do the rational thing and get their blood tested. But that isn't surprising. The surprising thing is that that number wasn't 100 percent because you should always be willing to hear information about your finances or your health.As many as 20 percent of the students were willing to pay cold, hard cash to avoid finding out that they had genital herpes. Another thing the researchers found - students who were in a good mood were more likely to avoid information than those in a bad mood. This may seem surprising, but it actually makes complete sense. When you're in a good mood, do you really want to ruin how you feel by discovering you have herpes?TASOFF: It's like an ignorance-is-bliss result.VEDANTAM: Think for a moment about the implications of information aversion. So many health and well-being messages are premised on the idea that people will act rationally when it comes to preserving their health. What if that isn't true for a sizable number of people?GANGULY: I think that we should consider whether scare tactics in advertising and things like that. I mean, whether that is a good technique to encourage people to get tested or not is questionable.VEDANTAM: When we come back, we're going to leave the lab and head out into the real world to see how information aversion plays out in everyday life. Stay with us.(SOUNDBITE OF MUSIC)VEDANTAM: This is HIDDEN BRAIN. I'm Shankar Vedantam. There's no question that fear is an effective way to change how people behave. When a parent tells a kid to fall in line or risk losing iPad privileges for a week, or when a boss tells an employee to come into work on time or risk getting fired, these often produce the desired effect. We use scare tactics in public service announcements all the time, like in this road safety commercial from Thailand...(SOUNDBITE OF CAR HORN AND TIRES SCREECHING)VEDANTAM: ...Where a speeding car runs into a group of pedestrians. Or this anti-smoking advertisement from Poland...(SOUNDBITE OF STRIKING A MATCH)VEDANTAM: ...Where a lit cigarette is transformed into a candle at the base of a tombstone.(SOUNDBITE OF CROWS CAWING)VEDANTAM: In Josh and Ananda's study, the majority of volunteers chose to get tested after being exposed to graphic images of herpes. This makes sense, says University of Illinois psychology professor Dolores Albarracin.DOLORES ALBARRACIN: If you induce a significant level of fear, you're going to get a comparable reaction on the behavioral side.VEDANTAM: Dolores and a team of researchers analyzed 250 studies done about the effectiveness of fear in transforming behavior. While the research shows fear, indeed, is effective, Dolores says it has limitations.ALBARRACIN: It does work better for one-time behaviors. So getting vaccinated - if I have a threat and there is an effective vaccine right after, and I just go in and get it one time, that's easy to do. The behavior is done right after you experience the emotion. Emotions are not that long-lasting, so it's going to have an effect. But if it comes down to following the right diet, we all know how difficult that is. And whatever fear you might experience at one point is gone the next day.VEDANTAM: This is the crux of the issue. If you want someone to do something one time, frightening them into doing it could be very effective. But if you want them to do something regularly and over a long period of time, fear might not be effective. In fact, some research suggests it could be counterproductive.Let me just have you start, if you don't mind, by just introducing yourself. And tell me your name.RITESH BANERJEE: Sure. My name is Ritesh Banerjee. I'm an economist.VEDANTAM: A few years ago, Ritesh and his colleague Giulio Zanella began looking at data about 3,000 American women who all worked at a large company. All the women were between the ages of 50 and 64, and they were all covered by an insurance plan that provided a free mammogram every year.BANERJEE: Which is perceived to be an important tool in the fight against breast cancer.VEDANTAM: This company made a real push to help women get screened for breast cancer. It would automatically schedule mammograms for staffers and then remind women about upcoming appointments. Screenings were conducted right at the company, so they were easy to get to. And the wait times were minimal. In other words, many of the barriers that keep women from getting tested were absent at this company.Ritesh wanted to find out how the decisions of women to get screened for breast cancer were shaped by information aversion. He obtained detailed information from the company about employees, including their health status and where they physically sat in relation to one another. He discovered that when one staffer was diagnosed with breast cancer, this dramatically changed the behavior of other women who worked in her vicinity.BANERJEE: We find that on average, when a woman is diagnosed with breast cancer, her coworkers - her immediate coworkers - female coworkers reduce their propensity to have a breast screening in the year in which the diagnosis takes place. And this impact is persistent for at least two more years after the diagnosis for that woman. Women in the closest proximity to the woman who was diagnosed with breast cancer learn of this information, their willingness to screen falls the most.VEDANTAM: Ritesh found that the severity of the disease was key. Women who had a coworker diagnosed with early-stage breast cancer were less likely to skip their annual screenings. But if a woman had a more aggressive case of breast cancer, her colleagues were the ones who were more likely to skip the screenings.BANERJEE: So it appears, in our data, that in groups where the stage of the cancer is late-stage, so not an earlier stage of cancer, that the avoidance behavior that we're observing is stronger.VEDANTAM: Women who knew a coworker who was dying from breast cancer were the most likely to skip their mammograms. Seeing a colleague suffer may have frightened these women from obtaining information about their own health.(SOUNDBITE OF MUSIC)VEDANTAM: Not long ago, I was playing sports with a friend on a weekend. I was trying to change directions quickly when my ankle gave out from under me. I felt a sharp pain and collapsed. In a matter of moments, my ankle started to swell up. It was like watching a balloon inflate. I got some ice on the ankle right away. But when the pain and swelling didn't subside and I found I could put no weight on the ankle, I decided I had to go to the emergency room. The pain in my ankle as my friend drove me to the ER was nowhere as bad as the pain in my head. Already, I had visions of needing surgery and being incapacitated for a long period of time. I desperately wanted to believe my injury wasn't serious.When I got to the ER, the triage nurse took one look at my ballooned ankle and told me it was broken. I argued with her and told her the pain wasn't that bad. When someone took my blood pressure and found that it was high, I insisted they measure it again until they got a lower reading. I didn't think of it at the time, but what I was experiencing was information aversion. I knew I had hurt myself, but I didn't want to know how badly. As it turned out, the ankle wasn't broken. It was just a very bad sprain.In the grand scheme of things, an ankle sprain is a trivial problem. It isn't cancer or heart disease or a serious infection. It isn't bankruptcy or like losing a job. But it made me realize that if I could experience information aversion for something so small, it's hardly surprising that people experience much more information aversion when the stakes are higher.People who avoid information rationally know that they would be better off if they fully understood the bad news. You should always be willing to hear information about your finances or your health. But deep in the brain, there are rules that tell us to avoid things that are unpleasant, painful or scary. Like listeners Jason, Annie and Nancy, we shut out the news we'd rather not hear. If we want people to pay attention to negative information, we can't assume that they will behave like rational robots. We have to communicate information accurately but also give people the capacity to process and deal with psychological pain. Fighting the ostrich effect means fighting a myth. Avoiding information doesn't mean you're a fool. It means you're human.(SOUNDBITE OF MUSIC)VEDANTAM: This episode of HIDDEN BRAIN was produced by Parth Shah. Our team includes Tara Boyle, Maggie Penman, Jenny Schmidt, Rhaina Cohen, Renee Klahr and Gabriela Saldivia. For more HIDDEN BRAIN, you can follow us on Facebook, Twitter and Instagram and listen for my stories on your local public radio station.Our unsung hero this week is Sarah Gilbert. Sarah's the executive producer of Morning Edition at NPR, and she's played an important role in getting HIDDEN BRAIN on the air. She's a very effective leader, decisive and clear and always empathetic to the concerns of people around her. She's British and tends to call people ducky. I thought I'd return the favor today. Thanks, Ducky. I'm Shankar Vedantam, and this is NPR.(SOUNDBITE OF MUSIC)VEDANTAM: Before we go, one absolutely vital piece of information. The term the ostrich effect isn't fair to ostriches. It turns out they don't shove their heads in the sand out of fear. Ostriches have underground nests. When they burrow their faces in the ground, they're actually checking on their eggs. It seems like even the ostrich knows while ignorance might be bliss, knowledge is power. Transcript provided by NPR, Copyright NPR.