KATY MILKMAN: We’ve sent several volunteers, all regular coffee drinkers, a sample of some nicely roasted espresso beans.
SPEAKER 2: There is a special blend of Rocket Coffee with a note and a small package of beans.
KATY MILKMAN: Our volunteers are replacing their regular morning coffee with a brand that purports to have higher caffeine levels.
SPEAKER 3: What do we have here? Rocket Coffee special blend. Well, that sounds promising.
SPEAKER 4: Some of this special blend Rocket Coffee. Just … put it all.
KATY MILKMAN: But since caffeine usually takes a little while to kick in, we’ll check back with our volunteers in a bit. In the meantime, we’ll be talking about a quirk of human perception that may change the way you think about everything from coffee to housework to knee surgery.
I’m Dr. Katy Milkman, and this is Choiceology, an original podcast from Charles Schwab. It’s a show about the psychology and economics behind our decisions. We bring you true stories involving high-stakes moments, and then we explore the latest research in behavioral science to help you make better judgments and avoid costly mistakes.
ERIK VANCE: My name is Erik Vance. I’m a journalist and an editor with the New York Times with the Well Desk, and I’m also the author of Suggestible You.
KATY MILKMAN: Erik is a biologist and science writer who grew up in a family that believed in faith healing. In fact, Erik didn’t see a medical doctor for the first time until he was 18. As a scientist. He was curious about some of the faith healing encounters he’d had as a child. They were experiences that seemed to defy rational explanation. As a science journalist, he went in search of some answers, and he started in Mexico.
ERIK VANCE: When I started working on my book, I was based in Mexico City, and this long tradition of faith healing and of shamanistic healing, and it’s very much a part of the culture. And one of the places I ended up in was San Pablito, which is in Puebla. It’s sort of this city that’s barely sort of hanging off of a mountain almost, a very steep town. It almost looks like someone sort of dribbled the city with a ladle under the side of the mountain, and it has a long history of curanderos, or healers. And I just wanted to talk to a few, and sort of see how their practices work, and find out a little bit more about sort of what goes into the healing shamanism in Mexico.
And so what I did was I visited this woman, Guadalupe Huaxi was her name, and she turned out to be this lovely woman based sort of right on the outskirts of town, and she didn’t speak any Spanish, so we sort of had to do a bit of three-way translating where she spoke in her indigenous language that she was comfortable with, and then her husband translated into Spanish. And while my Spanish is pretty good, I needed to translate it into English. So it was an interesting sort of process. I was having some knee problems, partly because I’m getting older and knees are one of the joints that go out. And the pain I was feeling was, it was sort of the dull aching to the side of your knee that a lot of people experience in their middle age, where it just sort of comes and goes. And that particular week, I’d been feeling a fair bit of it. I was doing a lot more running at that point. So I decided to have her deal with my knee.
KATY MILKMAN: Erik wasn’t quite sure what to expect. There were significant language and cultural barriers, and Erik had never experienced this particular treatment before.
ERIK VANCE: She started by cutting out these special paper talismans called amate, and she sort of laid these things out, and they would represent various evils and various problems that related to me. What’s interesting is we talked a lot about my personal life, and the things didn’t really have much to do with my knee. But you could tell that she was struggling a little bit because I am from a different culture. And she was a very kind, sort of open person. But she’s talking to someone through two different layers of translation, and she was struggling to sort of create a rapport with me, and I was trying to create a rapport with her. And this is an important detail, because a big part of traditional healing is that rapport that you have with your healer.
And then she said, “OK, now that we’re done with that part, I need to take out the bad blood out of your knee.” And I said, “OK, I guess that’s OK.” She said, “I’m going to suck it out.” At which point I sort of blanched a little bit. I was like, “I don’t know if I want you cutting open my knee and sucking my blood. I don’t think that’s a very good idea.”
KATY MILKMAN: For listeners who might be getting squeamish, not to worry. There’s no actual blood involved. Let’s just say that some of the details of the procedure got lost in translation. Then again, if Erik knew exactly what he was getting himself into, he still might’ve balked.
ERIK VANCE: She said, “No, no, no, sit down. I’m going to suck the blood out of your knee.” And she sat me down, and then she proceeded to sort of wrap her mouth around my knee. She didn’t make any incisions or anything, but she just started sucking sort of metaphorically the blood out of my knee, and then spitting it into this little packet that went with the talisman and some herbs that she was burning. All of it got put together, and then eventually disposed of behind the house. And it was a very strange experience. It involved a lot of the senses. There was smell, there was this woman sort of chewing on my knee. There’s a lot going on. And then when she was satisfied, that all of the pain had been taken out, she said, “OK, thank you very much. You should be good now.” And sent me on my way.
KATY MILKMAN: It’s probably safe to assume that having someone gently gnaw on your knee is unlikely to result in a measurable change in the joint, a change that would lead to any kind of healing. And it’s easy to dismiss these rituals as just rituals, but Erik did feel at least some pain relief.
ERIK VANCE: And what was interesting is when I left, I did feel relief in my knee. My knee did feel better. I was able to walk up the steep steps of this really steep town. And for a short time, felt no discomfort. I was really surprised, and I remember commenting to my colleague like, “Wow, my knee feels a lot better. I think I’m not feeling any pain walking up the stairs.”
KATY MILKMAN: And this was despite his well-practiced skepticism as a science writer.
ERIK VANCE: The effect lasted for probably the rest of the night. And then by the next day, I was feeling the knee again. But that’s more than I definitely have felt with a lot of different healers. I have spent many years studying and writing about the placebo effect and about belief in the brain, but that doesn’t make me immune to it. This is something that we all experience. And so in that respect, Guadalupe was very good at her job.
KATY MILKMAN: You’re probably familiar with the concept of placebos in the context of pharmaceutical trials. A control group of volunteers is given a sugar pill, which is a placebo, but no one in the trial knows if they’re receiving the placebo or the real drug. All the pills look the same. This procedure makes it possible to determine if the medication is effective without worrying that people might offer inaccurate reports, intentionally or otherwise, about any improvement in their conditions, simply because they know whether or not they receive treatment. The placebo ensures no one knows if they were treated or not. The placebo effect describes the fact that if one group of volunteers is given a sugar pill, and another isn’t given any treatment for an ailment, the volunteers given that placebo tend to actually experience at least some of the purported benefits of the treatment. What Erik is interested in is the power of this effect, the power of our expectations to change our health and well-being.
ERIK VANCE: Placebo effects and expectation and belief, they aren’t limited to the mountains of Puebla in Mexico, or really anywhere else. This is something very fundamental to who we are as a species. And so, as such, you can create them in a lab if you’re really clever. And one place where I really got duped, where the placebo effect was especially powerful, was in the lab of a woman by the name of Luana Colloca. And she’s an Italian researcher who at the time was based in NIH in Bethesda, Maryland. And she hooked me up to this machine that basically would be giving me electric shocks. She gave me two kinds of shocks. She gave me a one that was a number one in pain, which is sort of like a pinch, almost like a static electricity shock. And the other one was a six or a seven on my scale of pain, out of 10. And that one made my foot twitch.
And what they did was every time I saw a green light, they would give me the smaller shock. And every time I saw a red light, they would give me the larger shock. And for a while, they just went back and forth, green light, red light, green light, red, and it got to the point where every time I saw that red light, they had a little pause just after the light would flash. They let you think about it. And you’d be like, “Oh, here it comes. Here it comes.” Then she went back and forth until on the last round, it felt like, we’ve been doing this about half an hour. And it felt like they’d maybe turned up the green light, the low shock, just a little bit, from one to two, but the red light of course is awful as ever. And when she came in at the end of the study, Dr. Colloca said, “Great job. Thank you for participating. By the way, on that last round, we gave you the large shock every time.” When I saw the green light, I didn’t feel that pain. My foot didn’t twitch.
KATY MILKMAN: By the end of the experiment, Erik had been receiving the same high shock for both the red light and the green light, but he felt significantly less discomfort during the green-light shock.
ERIK VANCE: This was not a matter of me imagining things or telling myself that it was less pain. I felt less pain. And it was this very obvious clear example of a placebo effect and the power that your brain has to basically step in and moderate your experience so that your expectation matches your belief. And you’d think I would be smarter and savvier than I was. You’d think I’d be able to spot these things. But here’s the thing that you don’t realize is, is no matter how much reading you do, you can’t fight your own brain. And the way I often describe it is almost as a theater. Theaters, they have sets, they have costumes, they have lines, and it’s a performance. And to some extent, all of these things, and any experience in medicine, involves some element of performance.
KATY MILKMAN: In addition to what Erik might call the set and costumes, or the setting where you’re having an experience, researchers can heighten the subject’s perception of efficacy by using what’s called an active placebo. That’s a placebo that actually generates some kind of sensory effect, a bitter taste in a pill, or a sound or vibration in a device that prompts you to think it’s working. Erik had another particularly vivid experience in Mexico with what you might charitably call a very active placebo. Hundreds of them, actually.
ERIK VANCE: This guy in a town called Huautla had me stick my arm in an anthill of very painful biting ants. And I stuck my arm in the hill and waited a couple of minutes. And sort of lifted it, and my arm was just teeming with ants, and they all were biting me, very angry clearly. And he said, “No, no, no, this is good for …” I had some forearm pain. “They will heal your pain.” And of course, there’s no science to back this up. It’s clearly a placebo effect, but it’s a very powerful, active placebo because it’s very painful and really uncomfortable.
We were working on a story where I was comparing the experience of placebo in a laboratory versus the experience of placebo in some of the places I had been, and Huautla is very famous for its traditional healing. And so I thought it’d be an interesting place to have conversations with people about healing and about expectation. And what I was very surprised there was this particular shaman, he was well aware of all the things that I was talking about when you talk about expectations, when you talk about theater, this is not new, it wasn’t new to him. It’s not new to most shamans. They understand that performance is part of the game.
KATY MILKMAN: Erik Vance is a journalist and editor with the New York Times Well Desk. He’s also the author of the book Suggestible You: The Curious Science of Your Brain’s Ability to Deceive, Transform, and Heal. You can find a link in the show notes and at schwab.com/podcast.
While the experiences that Erik describes may seem exotic or mystifying or scary, Erik insists that they do share something with Western medicine: the importance of setting expectations. When you go to visit your doctor or dentist or physiotherapist, you’re presented with numerous cues: an exam table, medical lights, lab coats, and so on. These things all have practical and important functions, but they can also prompt expectations of a positive outcome from treatment. Maybe you can think of a time when you went to visit your doctor to complain about some issue, and your doctor sent you on your way with nothing more than reassurance. Chances are good that you felt a bit better physically, just by virtue of experiencing the environment of your doctor’s office and anticipating some kind of improvement in your health, in addition to the calming effect of your doctor’s reassurances. Expectations can have measurable effects on how we feel in many other contexts as well. Remember those volunteers from the beginning of the episode, the ones we sent that high-caffeine coffee to?
SPEAKER 5: I love coffee. It just gives me a shot in the arm to help me go on with my day.
SPEAKER 2: Yeah. So in terms of my energy level today, I think it was more or less the same as my usual coffee experience.
SPEAKER 6: Me, I think I overdid the coffee this morning. And so I’m now trying to just counter the caffeine effects by having something to eat.
SPEAKER 4: I hate to break this to you, but we sent you decaf.
SPEAKER 7: It’s decaf.
SPEAKER 4: We sent you decaffeinated coffee.
SPEAKER 5: I’m sorry.
SPEAKER 2: That’s so funny.
SPEAKER 6: Actually, if you hadn’t told me it was decaf, I probably just would have thought that my day, I was feeling good because of the coffee.
KATY MILKMAN: A rather unscientific and sneaky experiment set expectations for our volunteers about how they’d feel after drinking our high-powered coffee. They anticipated feeling awake, mentally alert, maybe even a little bit jittery.
That placebo effect is significant enough that it can even improve medical outcomes for patients undergoing certain types of surgery. There’s a legitimate medical practice of “sham or placebo surgeries.” This is where a control group of patients in a surgical trial is taken through the consultation and pre-op phase and then give anesthetic and even incisions, but no actual meaningful surgery is performed. In some cases, these fake surgeries have resulted in decreased pain and increased mobility for a percentage of the patients given this treatment. The thing is, the patients don’t know if they’ve received a real surgery or a sham version, just like in double-blind drug studies.
You can begin to see the power of expectation in the treatment of pain. And even though Erik Vance could clearly see that his treatment by a faith healer in Mexico had no surgical component, he still felt some measure of relief after the ritual. What is it about our minds that can cause these very real effects?
Alia Crum is an expert on how our beliefs and expectations, or our subjective mindset, can affect the outcomes we experience. The placebo effect is the most famous way our mindsets shape our experiences, but our expectations and mindsets can alter many outcomes beyond the realm of medicine. Alia is an assistant professor of psychology at Stanford University, and the principal investigator of the Stanford Mind and Body Lab. She joined me on the line from her home in California to talk about her research on placebo effects and subjective mindsets.
Hi, Alia. Thank you so much for joining me today.
ALIA CRUM: Thank you. It’s great to be here.
KATY MILKMAN: Alia, could you talk a little bit about the placebo effect? What is it, and what do we know about it from research done by you and others?
ALIA CRUM: Sure. Yeah, the idea of the placebo effect came about because many providers were actually openly giving people sugar pills, or red pills, or things that didn’t have any substance, and they would find beneficial effects. But our modern understanding of the placebo effect comes from the randomized placebo-controlled trial, in which an active medication is compared to the effects of a placebo medication. And what that allows us to do is to separate the effects of the chemical or pharmaceutical agent in the active medication from what was referred to as the nonspecific effects that might occur as a response to just taking a sugar pill. Now that design is important for understanding and scientifically testing the efficacy of a new drug, but what that obscures is the effect of the placebo. First of all, it obscures the fact that the total effect of that medication will be the active pharmaceutical properties on top of the active ingredients in a placebo effect.
So what our work and others around the world have been doing—Ted Kaptchuk, Irvin Kirsch, Catherine Hall, Luana Colloca—many others are studying this and start to unpack the mechanisms of the placebo. So what actually drives or makes up a placebo effect, and we’ve sort of broken it down into three things. The first is the body’s natural ability to heal. If you did nothing, in most cases, the body has a natural ability to heal itself with time, and that alone shouldn’t be discounted. But second is the mindset. So beliefs and expectations can elicit healing in part because they activate the body’s natural physiological abilities to heal itself. And third, those mindsets don’t come out of nowhere. They are situated into a social context, a social context that’s made up of just the symbolism of taking a pill and swallowing it with water, the symbolism of being in the presence of a doctor in a white coat who gives you a prescription, things around that, such as the branding of the drugs or the doctor’s bedside manner.
All of these can be important factors in shaping our mindset, which can in turn activate our body’s physiological processes. So you can see here, the randomized controlled trial is a good model for testing the efficacy of a medication. It’s a pretty poor model for understanding the richness that’s involved in these, what’s formerly known as non-specific effects. They’re actually very specific, and we can measure them, and we can leverage them in medicine.
KATY MILKMAN: That’s really helpful. I’ve been thinking a little bit about your 2007 paper on housekeepers and weight loss, as well as your more recent work on milkshakes. And I was wondering if you could describe those studies for our audience.
ALIA CRUM: Yeah, of course. In the 2007 paper, Ellen Langer and I had a very simple question, and that was, might the benefits of exercise arise in part due to a placebo-like effect? We know in medicine that in some cases, a large proportion of the benefit of taking a medication comes as a result of just believing that you’re in good hands, that you’re taking an effective medication. And so to test this in the context of exercise, we worked with a group of women hotel housekeepers, and we realized that they were actually getting good exercise. So they were getting far beyond the surgeon general’s requirements, just by showing up to their job each day. Cleaning hotel rooms is a very physically demanding job. But what we also realized was that most of them didn’t view their exercise in that light. In other words, they had the mindset, or the assumption, that work is just that—hard, painful work.
So we wanted to see what would happen if we could shift their mindset to viewing their work as good exercise, to viewing themselves as getting adequate amounts of exercise in order to receive the benefits. So to test that, we took these women, and we randomized them to two conditions, or 84 women in this study. Half of them we told that their work was good exercise. It satisfied the surgeon general’s recommendations for healthy lifestyle, and that they should expect to see those results. So we were able to compare these groups before the control group was given any information. And what we found was that the women who received this information to view their exercise in that light lost weight, dropped blood pressure and body fat, compared to the control group of women who hadn’t yet received that information.
KATY MILKMAN: I love that study. And I know you have another really interesting paper that looks at a similar phenomenon when it came to milkshake drinking. Would you mind describing that one as well?
ALIA CRUM: Yeah, yeah. So after I ran the room attendance study, I was just like, “Wow, it’s this placebo effect. We’ve seen it in medicine. Where else might this take hold? We looked at exercise. What about diet?” So for this study, we had people come to our lab. This was done at the Yale Center for Clinical Investigation. And we had them drink two milkshakes separated by a week. So it was the same person drinking the same milkshake at two different time points. At one time point, they were told that the milkshake was a low-fat, low-calorie diet shake, 140 calories, no added sugar, and so forth. And the other time point, they were told that it was an indulgent 620 calorie, high-fat, high-sugar milkshake. And what we found in that study was that even though the milkshake was exactly the same from a nutrition standpoint, at both time points, what they believed they were drinking changed their physiology in important ways.
Specifically, we found that when they thought they were drinking an indulgent milkshake, their gut peptide ghrelin, which is a physiological marker of satiety, dropped at a three-fold rate compared to when they thought they were consuming a more sensible, healthy-diet-type shake.
KATY MILKMAN: It’s just fascinating how this can work for you or against you. Like when the room attendants believed they were getting exercise, that was good for them, they did see health improvements. And when people believe they’re eating a low-calorie shake, that’s bad for them because it leaves them unsatisfied and wanting more. Could you describe a little bit about why you think it is that mindset can have these incredibly powerful effects and change our physiology?
ALIA CRUM: Yeah. A couple of reasons here. So we think that mindsets have an effect on our health through four pathways. The first is through our emotions. So when I think about the room attendance, when you feel like you’re getting good exercise, that makes you feel better about yourself. They could have had more positive moods throughout the day, better self-efficacy, sense of self-worth. And we know through a lot of research that a positive affect and low negative affect can have physiological repercussions. Another pathway is through attention. So what we believe to be true about the world changes what we pay attention to. And so you can see for these room attendants, now they’re being told that your work is good exercise, you’re noticing at the end of the day the way your muscles are sore, and you might feel fatigued, but you attribute that to having engaged in good exercise, not to the fact that your work is so hard and tiresome.
So affects, attention. It can also change your motivation. So we couldn’t be sure in the room attendant study, but they might’ve been putting a little bit more oomph into their making the beds, or were a little bit more motivated in other ways. But even aside from motivational or behavioral effects, mindsets can change physiology directly, and they can do this in a number of ways. With the diet study, what we think is going on here is that our bodies are responding, not just to the presence of nutrients in the system, but to our expectation about the future of nutrients. So as humans, we’re trying to enable survival, not just by reacting to the world, but by anticipating what will occur in the world in the future.
So in this study, and you can imagine this yourself, if you feel like you didn’t eat enough food, I’m eating sensibly, but it wasn’t enough, it wasn’t indulgent, your body responds by saying, “Wow, I must not have gotten enough nutrients. I need to rev up these hunger signals so that it will tell my brain to keep searching for more food.” So it starts to make sense when you really pack it down and break it down. I think a lot of people are surprised by these findings, but actually, the fact that our mind and our mindsets more broadly can influence our physiology and our health is really not that surprising at all, when you understand the mechanisms at play.
KATY MILKMAN: That’s really interesting, I think a lot of our listeners will be interested in the question of how we can leverage these placebo effects, these mindset effects, to make it easier to achieve goals or to improve our lives. Do you have a sense of how people can themselves achieve more if they are familiar with this research?
ALIA CRUM: Yeah. I think that the most important thing about this work, about mindsets, is to realize that we have them, that we aren’t just reading the world as it is. We are filtering reality through our own mental filters. And we’re picking up on things based on our pre-existing assumptions, beliefs, expectations, or mindsets. And I think when we start to realize that, a whole new world opens up for us. We can stop asking, “What do I need to do differently?” Or “How do I change my life circumstances?” All of those things are good, and don’t get me wrong, I think where possible, people should be changing their behavior and their life circumstances if that’s possible. But there’s a whole range of influence in terms of improving our lives that we can have by being mindful of the mindsets we have and deliberately shifting those mindsets towards more adaptive ones.
I think about this a lot in my own life, raising my child—she’s turning two in a few weeks. And the mindset I’m most focused on with her right now is mindsets about healthy eating. One thing we learned from the milkshake study was that having the mindset that you’re eating healthy or sensibly is actually not a very useful mindset to be in because it leaves you feeling physiologically not satiated. We also know from other work that that mindset leads people to assume the food’s going to taste worse. So we’ve been really working on how we can create a mindset in which she views healthy foods as delicious foods, even indulgent foods. And setting that mindset hopefully will help her have a better relationship with food throughout her life. In other situations, it might be more important to focus on mindsets about stress.
For example, all of us are, especially in the context of this pandemic, dealing with massive amounts of stress, and yes, again, where possible, we should reduce stress and improve our lives in the ways we want. But what people overlook about stress is that we only stress about things we care about. So it’s sort of the other side of the coin of our values is feeling stressed. And so if we can change our mindsets about stress, we can improve our lives by reconnecting to our values and utilizing that stress to increase our well-being and performance.
KATY MILKMAN: I think that’s actually a really great note to end on. So let me just thank you so much. It was really wonderful to have you on the show. I appreciate you taking the time to do this.
ALIA CRUM: Thank you, Katy. It’s such an honor to be here. I’m such a huge fan of your work as well. So it’s great to connect and chat about these things.
KATY MILKMAN: Alia Crum is an assistant professor of psychology at Stanford University and the principal investigator of the Stanford Mind and Body Lab. I have links to her work in the show notes and at schwab.com/podcast.
Your mindset can have a big impact on your portfolio, especially if you allow your emotions to get the better of you—like during bouts of market volatility, for instance. The Financial Decoder podcast explores the ways emotional and psychological forces might be affecting your financial well-being. And it covers strategies to help you make smarter financial decisions. Check it out at schwab.com/financialdecoder or wherever you get your podcasts.
As Alia Crum mentioned, we aren’t just reading the world as it is. Our brains filter reality based on our beliefs and expectations. Knowing that’s the case opens up possibilities for deliberately adjusting our mindsets to help us achieve our goals. Stanford psychologist Carol Dweck has proven that when we adopt a growth mindset, viewing our abilities and intelligence as works in progress that aren’t fixed, but capable of improvement through effort, we can achieve more. And Alia has shown that when we think of healthy foods as indulgent, and view chores as sources of exercise, better outcomes ensue. While Erik Vance explained that you’ll experience the placebo effect no matter how much you’ve read about it, shifting your mindset can help you leverage this particular behavioral quirk to your benefit. As Alia mentioned, managing performance stress, like the stress you feel before giving a big presentation or when working through a tough problem at your job, is an area where expectations matter tremendously.
If you view that kind of stress from work, relationships, or even your investments as debilitating, it will be. But if you instead adopt the view that stress is enhancing, and can help you thrive and achieve more, Alia’s research has shown your body will literally secrete different and more helpful hormones in response to the same stressors, helping you achieve better outcomes. We talked about the power of reframing performance anxiety as excitement in a previous episode of Choiceology—and how powerful that can be—and that finding is closely related to the power of beliefs and placebo effects. By recognizing the way our beliefs shape our reality, study after study has shown that we can help set ourselves up for success.
You’ve been listening to Choiceology, an original podcast from Charles Schwab. If you’ve enjoyed the show, we’d be really grateful if you’d leave us a review on Apple Podcasts. It helps other people find the show. You can also subscribe for free in your favorite podcasting app. And if you want more of the kinds of insights we bring you on Choiceology about how to improve your decisions, you can pre-order my forthcoming book, How to Change: The Science of Getting from Where You Are to Where You Want to Be, or sign up for my monthly newsletter, Milkman Delivers, at katymilkman.com/newsletter. Next time, I’ll speak with behavioral scientist Ido Erev about the gap between the way we perceive risk when it’s described to us versus when we experience it. I’m Dr. Katy Milkman. Talk to you soon.
SPEAKER 9: For important disclosures, see the show notes, or visit schwab.com/podcast.