Weight scale

Can a Scale that Leverages Behavioral Economics Help You Lose Weight? (Podcast interview with Professor Dan Ariely)

Why do we repeatedly make decisions that we know will undermine our goals – like procrastinating, or spending too much money?

Nowhere is this sort of self-defeating pattern more evident than in health-related behaviors. For example, in order to successfully lose weight and maintain weight loss, we need to make a variety of different choices on a daily basis. Yet, as we’ve addressed here before, most of us struggle to consistently make the right decisions, even when we know what we should be doing.

Advances in digital technology have given us unprecedented access to data through wearable devices, which can provide continuous information about our bodies and physical performance. But humans are not robots, and what we do with that information does not always support our long-term goals. That brings me to my guest today.



In this show, I speak with Dr. Dan Ariely. Dan is the James B. Duke Professor of Psychology and Behavioral Economics at Duke University. He has dedicated his life, specifically, to understanding irrational behaviors. He has long recognized that even with access to useful information, we don’t always make the right choices. Furthermore, how we respond emotionally to health-related data can be counterproductive.

The reality is that the environment matters a lot, much more than we think Click To Tweet

Body weight can be a particularly treacherous metric in this respect. Due to shifts in water balance in the body, your weight can fluctuate up and down each and every day, for reasons that often aren’t related to changes in adiposity (body fatness). For instance, you may have eaten a salty dinner the night prior making you hold water the next morning while on the scale. Even stress can affect body fluid balance. And while these kinds of day-by-day weight fluctuations aren’t important for your weight – they just happen – the short-term emotional impact of seeing that you’ve gained weight can be demotivating, and can ultimately result in aversion to the scale entirely.

Dr. Ariely became interested in this phenomenon, and resolved to design a better scale that took these psychological tendencies into account.


A Smart Scale

Meet Shapa.

As you can see, Shapa is a unique scale. While the scale does measure your weight, and transmits information to the app via Bluetooth, it does not display it for you. Instead, the scale records your body mass (also captures bone density and muscle mass), and analyzes the information in the broader context of your weight over the past three weeks.

That way, if you’ve gone up a little bit due to a random fluctuation, it doesn’t interpret that as a meaningful increase. Instead of giving a number, the app presents feedback on a five-point scale, based on your past weight trends, and discounts anything within one standard deviation of your running average.

Like I said, body mass can be a misleading proxy for health, but it’s still useful. Research suggests that 75% of participants in the National Weight Control Registry (individuals have maintained at least 13.6 kg of weight loss for five years) weigh themselves on a regular basis. Getting feedback about your weight is a good thing – this scale just modifies the form of that feedback. 

To learn more about Shapa, and about Dr. Ariely’s work, check out the interview below!

Info not about historical accuracy. It’s about helping you understand relationship b/w cause + effect. Click To Tweet



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Kendall Kendrick: HumanOS. Learn. Master. Achieve.

Dan Ariely: And we gave some people our scale and those people lost 0.7% of their body weight every month.

Dan Pardi: Greeting listeners, today I am thrilled to welcome Professor Dan Ariely to Human OS radio. Dan is a Professor of Behavioral Economics at Duke University. His work looks into how humans make decisions and how rational or irrational we are on a daily basis. [00:00:30] He is the author of numerous best-selling books including “Predictably Irrational,” “The Honest Truth About Dishonesty,” and his latest book “Payoff: The Hidden Logic That Shapes Our Motivation.” He has also given numerous TED Talks and other popular lectures on decision science that you can find online. And he advises multiple companies to help them create products based off of better fundamental assumptions about what really drives human behavior, including a new body weight scale called Shapa that we will discuss today. Dan welcome to the show.

Dan Ariely: Lovely to be here.

Dan Pardi: [00:01:00] We think we have much more control over how we live than is reality. Tell us about some of the fundamental paradoxes of how we think we decide and behave and how we really decide and behave and what’s driving that.

Dan Ariely: Yeah, so maybe my favorite example of this is a study with a company called Express Script. And Express Script is a PBM, they basically manage pharmaceutical benefits and they do all kinds of things, among [00:01:30] them they send people medication over the mail. So imagine that you have like a long-term illness and Express Script send you medication over the mail every 90 days. And one of the things they want to do is they want to switch people from branded medication to generic medications. And they send people letters and they say, please, please, please switch to generics. You will save money, we will save money, your employer will save money, the world will be a better place, but nothing happens. [00:02:00] People don’t switch. So they try all kinds of things including for one year they told people if you switch this year, we will reduce your copay to zero. Right, sounds like an amazing deal right?

Dan Pardi: Sure.

Dan Ariely: But almost nobody switched. So at that point they came to talk to a group of social scientists and they say what’s happening, how can it be that we offer [00:02:30] people to switch from a $20 amount copay, not with the regular $5 a month for generic, but to free and people don’t switch. And they said could it be that people hate generic medications so much that even free is not working? And we basically said look, this is possible, but it’s also possible that people just hate doing anything. We said, let’s think about the little details of what’s going on. So, when you look at the little [00:03:00] details you say people start with branded and they could do nothing with branded or they could do something, return the letter, and end with generic. But it’s really what we call a confounded design, it’s two things at the same time. It’s branded versus generic, but also doing nothing versus doing something.

So, which one is it, the doing nothing versus doing something or the branded versus generic. So we said what if we reversed things, what if you send people a letter and you say if [00:03:30] you don’t return this letter we are going to switch you to generic automatically and if you want to stay with branded then you need to return the letter to us. So reversing it, the generic, switching to generics become the no action path, but if you want to stay with branded you have to return the letter. So it turned out that’s illegal, it’s illegal to switch people’s medication so they did something else, what is called forced choice. [00:04:00] They basically sent people a letter and say, you can’t do nothing, if you don’t return this letter we will be forced to stop your medications. But when you return the medication you could choose generic at this price or branded at this price, there’s no free anymore.

What happened? 80 to 90% of the people switched. Right, so what does it mean, do people like generic or like branded, people just don’t care what people hate is returning letters. [00:04:30] And when they describe this experiment to people sometimes they say oh come on, wouldn’t people return a letter if it could save them $15 or $20 a month every month for the rest of their lives? And then I said okay, let’s think about their own lives, how many of us have a subscription or membership to something that we should be canceling? But we just don’t feel like it today.

Dan Pardi: Next month.

Dan Ariely: Yeah, that’s right. So one part of this if you think about the insight from social science is that we procrastinate, [00:05:00] we don’t think about long term. But the second one and I think this is the more general principle is that the environment matters and what we often think is that our actions are driven by our preferences. That we have these preferences running in our mind and we just act based on them. The reality is that the environment matters a lot, much more than we think and we often do what’s easy to do, not what we want to do. [00:05:30] But then, we explain it to ourselves as if we did it based on our preferences and because of that we don’t see how much the environment really influences our behavior.

Dan Pardi: Tell me about interpersonal differences of this behavioral phenotype. So on one polarity you could call them the environmental reactor right? This is the person who is deciding mostly based off of their surroundings and their built environment, their culture. On the other hand, the other polarity we all recognize the person who is more of a rational actor. A person who can set a goal to go to the gym five days a week and does so. The person who can decide to save [00:06:00] x amount a month, the person who cancels their subscriptions. So, first of all does this polarity really exist and if so, what is that fractional breakdown across the population. Do we really see these sort of extremes of people and what are the forces that can maybe shift somebody in one direction or the other? Even if you do have pretty good controls over some of your behaviors, you also might let that subscription keep going even though you know you want to cancel it. But you do go to the gym five days a week. What about interpersonal differences?

Dan Ariely: Yes and the last part of your question I think is the most important one. In general [00:06:30] there is a personality trait of great self-control that ends up being important. And it’s about, it’s not so much about being like the Dalai Lama that you can just stare at the cookie and not care, but it’s more about finding little tricks of overriding temptation. So basically saying if I want to do this, I make a note for me I put it in my calendar and I do it. I make a promise to other people, I don’t start on other [00:07:00] things before I do that.

It’s more like some people have personal tricks how to trick the system and get them to do things that are good for them in the long term rather than the short term. And that turns out to be an important personality difference. Not so much a type I would say, but it’s a personality difference, but you’re absolutely right that it doesn’t seem to describe people as a personality across all domains. [00:07:30] So you could have somebody who is really good at everything at work, but terrible at all the things that they do at home. Or somebody who is really good when it comes to promises we make to other people, but not good to things that we do personally. So, certainly there is important differences.

Dan Pardi: Certain people can have things stay in their surveillance but then the things that are not, that are less important [00:08:00] that they care about a little bit less, most humans tend to revert to the sort of behavior of taking the easy path.

Dan Ariely: Yeah, and I’m not sure you would call it care a bit less, they end up doing less of it, but some people for example have a really hard time with anything that has to do with food. It doesn’t mean that they don’t care about health or eating or so on, they just have a really hard time with that. And there are differences in that. And by the way, that’s true for lots of personality. [00:08:30] Psychologists for a long time have looked for these personality traits to describe how we are across many domains, but the reality is that the way personality works is that it’s different per domain. So you can say do you like the color red, maybe you like red shoes and red cars but not necessarily red jackets. Or red home, or red pillows. But the fact that you are working on a particular type of approach to [00:09:00] life in some domains doesn’t necessarily mean that you do it across domains.

Dan Pardi: Is the right approach to try to then affect control over something that you do care about to increase your motivation somehow for interventions to try to make you more motivated to go out and achieve it? That’s probably a common approach, is that the right approach?

Dan Ariely: My metaphor for behavioral change is thinking about every task like sending a spaceship to space, a ship to space. [00:09:30] And there basically two types of problems. There’s the problem of friction, resistance and there’s the problem of fuel. And the first thing to do is to take the part of this resistance is to say how do you reduce friction. So, if you want to go to the gym, how do you make it so that it’s the easiest thing to do, right, you already packed your clothes or maybe your clothes are in the gym. Or maybe you [00:10:00] are setting to meet a friend very close. You basically make the process have less friction.

And then the second thing is to say how do we add more motivation, how do we add to the fuel. And for example, you could add some social responsibility or give yourself points, or you could say every time I finish exercising I go to a sauna. You do things that take what you do and give [00:10:30] you an additional reward. Doing the right thing for the wrong reasons.

And the first step is usually to try and just reduce friction. Think about your refrigerator at home, if you open the refrigerator and ask yourself what do I want to eat, most likely at eye level you don’t have the healthy stuff. Your healthy stuff is tucked in a drawer at the bottom that is opaque. If you want to make it slightly easier to eat [00:11:00] the healthy stuff, you want to put fruits and vegetables at eye level and take the unhealthy stuff and hide it in this opaque drawer.

That’s the first thing and then the second thing is to create some extra motivation for yourself. And this could be about social recognition, it could be about buying yourself something, it could be about the promise, it could be about the rule, it could be about the ritual. There’s all kinds of ways to give yourself extra motivation, that’s kind of the second part of [00:11:30] the story.

Dan Pardi: With regard to weight loss in January, that’s probably the focus of many people in the United States. Many people are trying to lose at least a few pounds that they gained over the holidays. One, you can modify your environment, so make your environment have better choices and make the choices that aren’t so good less visible, harder to obtain or remove them entirely. And then also do some things that make your behaviors rewarded. Either you do something that you like doing afterwards or you do something that gets some social recognition from your friends. [00:12:00] And I know that you’re working on a new product called the Shapa scale. So, tell us a little bit about this scale. How is it different than a normal scale?

Dan Ariely: Yes, so first of all Nati, my co-founder and I started thinking about weight loss and when you think about weight loss from a psychological perspective you want to ask the question of what in your environment reminds you about health, what is it. And [00:12:30] the answer is it’s basically the scale. If you have some gym equipment it might be the gym equipment, but a scale is the only one main thing that reminds you about health. And Nati remarked correctly that he has a scale aversion. That stepping on the scale is a very, very unpleasant step for him. And he actually did a study, took a scale to Starbucks and asked people to stand on the scale and he found that almost nobody was willing to stand on the scale even if he paid them. [00:13:00] And then if they did stand on the scale, the very few people that did, had all kinds of stories about why they were wearing their heavy cotton today or something else.

So we said okay, the scale seems to be a really important element, but people have a scale aversion and they don’t like it. And then we looked at research on the scale and it turns out it’s really good to stand on the scale every day. You remind yourself that you want to be healthy. It’s good to stand on the scale in the morning not in [00:13:30] the evening because in the morning you remind yourself you want to be healthy you eat a little bit less for breakfast. If you stand on the scale in the evening it’s too late you just go to bed, you wake up the next morning you forget the whole thing.

Dan Pardi: Can’t do anything about it then.

Dan Ariely: That’s right. Weight also fluctuates a lot and weight fluctuates creates two things. The first one is what we call gain aversion. So in behavior economics there’s the notion of loss aversion, that we hate financial losses much more than we enjoy equivalent financial gains. In [00:14:00] weight it means that a day that you gain two pounds are really miserable. Days that you lose two pounds are happy but they don’t balance each other out. So imagine somebody that doesn’t gain or lose weight but the weight fluctuates by two pounds up and down, overall the experience is going to be negative and then they’re going to stop weighing themselves.

And then another thing that we find is that people expect their body to react very quickly. People say if I’ve been [00:14:30] a diet for a whole day, I started yesterday morning I was on a diet the whole day, I need to see something today. Right, it just seems like the laws of physics right. You haven’t eaten much, what’s going on? But of course the body doesn’t react this way so what happens is the body can react in ten days, two weeks and that creates tremendous confusion and annoyance. Like you’ve been on a diet for three days, you step on the scale [00:15:00] your weight went up by half a pound. Then you do a day of Netflix and cheesecake and your weight goes down. You say to yourself what’s going on here?

And by the way, this is true for lots of biological states. We expect the body to react very quickly and if it doesn’t we get very confused. So we said let’s separate the act of stepping on the scale from the act of getting feedback. So we created a scale with no display. The people step on the scale in [00:15:30] the morning we say congratulations you’ve done the right thing, you stood on the scale. That’s what you’re supposed to do, that’s the right behavior. And then we do give people feedback but we do it in a five point feedback scale. You’re just the same nothing happened, slightly better, slightly worse, much better, much worse. And these are kind of bands that are the running average of the last three weeks.

And the real change here is to say information is not about historical accuracy, [00:16:00] it’s about helping you understand the relationship between cause and effect. If you started exercising at some point it would show that your trend is going in the right direction. It might not be very quick, but we’ll show you when the trend is actually showing the right way. If you stopped exercising things are going in the wrong direction, we’ll start showing to you when we have confidence that this is actually in the wrong direction.
The other thing we’re doing is we celebrate when nothing bad happens, right [00:16:30] when you stay the same this is actually quite good. You mentioned earlier that lots of people gain a few pounds at the end of the year. If we could just get people, that’s a very common pattern, people gain four or five pounds at the end of the year and never lose it. If we could just get people not to gain those pounds, it would be a tremendous success.

So we did a large study, we went to a call center. These are relatively low income, relatively obese people. And we went [00:17:00] there because it’s easy to change the behavior of people who are really interested. It’s much harder to get a group of people who are not doing that well from a health, weight or financial perspective and try to change them. And we gave some people the regular scale and those people gained a little bit of weight every month. And we gave some people our scale and those people lost 0.7% of their body weight every month. It’s kind of an amazing [00:17:30] when you think about it just looking at the scale and changing our perspective on it can make it to a very appealing tool.

And in our study 80% of the people stood up on the scale 6 times or more per week. Basically the moment you take this number out the scale becomes much more appealing, people are much more interested, they stand on it, they remind themselves and then they take [00:18:00] the right steps. Now, this was 0.7% of body weight you know the ideal is 1, there’s still some room for growth, but it’s wonderful that just changing the scale gets you really a long way toward our goal in terms of body weight. And as a social scientist it’s kind of opened my eyes to say what if we took the social science lens and looked at lots of things around our lives. What other products would we [00:18:30] change, improve, look differently.

Dan Pardi: So the act of stepping on a scale has potential benefit, but the punitive nature of the fact that there is natural fluctuation to weight even if it’s heading in the right direction, will focus people’s minds on the positive aversion to gains.

Dan Ariely: That’s right.

Dan Pardi: And that will overall for some people shape the experience as being a negative one. In this case since you’re not giving feedback directly about a precise weight measurement, that you remove that barrier and people are more likely to step on that [00:19:00] scale more frequently. And as a result that morning trigger is then going to potentially stimulate better activities that actually get you results day by day and that did lead to more weight loss than a regular scale.

Dan Ariely: That’s exactly right. And a lot of diet programs, what they do is say don’t stand on the scale every day, stand once a week. And it’s kind of a hack to try and deal with this, but it’s not the right way to deal with this. The right way to deal with this is just to say [00:19:30] let’s give different granularity of information, let’s make the information more useful rather than not step on the scale.

Dan Pardi: The Shapa scale people stepped on it six times a week, how many times did people step on the normal scale in that same study?

Dan Ariely: So basically they don’t.

Dan Pardi: They don’t use it?

Dan Ariely: Yeah.

Dan Pardi: Right.

Dan Ariely: I mean, that’s the results from the regular scale. Right, you get the regular scale, it gives you an unpleasant number and very quickly it ends up under the bed or [00:20:00] you know, hiding somewhere. Even looking at it is unpleasant.

Dan Pardi: Right. Do you think that this scale is particularly good for people that are wanting to lose weight, what about people that now that they’ve lost weight, are they going to want to continue to use it for weight maintenance? Are people going to continue to use this scale years out?

Dan Ariely: So one thing, we went to this call center and we gave it to everybody right. So we didn’t want to do a study that basically said who want to lose weight and the people who don’t want to lose weight. We didn’t [00:20:30] want to have the self-selection, so we went to a call center and we gave it to all the employees. And so there was a range of people who want to lose more or less, many of them are not that interested, but we got to a whole range of people.

The other nice thing about this five-point feedback mechanism is that we can adjust it depending on where people are in their journey. [00:21:00] So we right now we have a whole [inaudible 00:21:03] deviation dedicated to nothing that is happening. Slightly better, slightly worse, much better, much worse, nothing that is happening. But as people arrive at different places in their weight loss journey, we adjust the algorithm to give more weight to what their current goal is.

And we have lots of ideas about how [00:21:30] to do it, we also have an algorithm for weight gain, for either people with anorexia or women who are pregnant and want to gain weight but in a specific approach. But you’re absolutely right that the scale needs to, the feedback mechanism needs to adjust based on the person’s goal and to give them positive feedback when they’re in that stage. So a regular person with a regular scale [00:22:00] if they reach their ideal weight the scale doesn’t tell them, great, it still shows you went up by over two pounds or down by over two pounds and you keep on worrying about it even if it’s not the right thing. Our scale is designed to take that into account and give people the sense of you’re on the right track, you’re doing the right thing.

Dan Pardi: Is there a way for people to see what their actual weight is? Can you dive three steps down [00:22:30] into the app to actually get there?

Dan Ariely: Yeah, so in the first version of the app with the study that I just described to you we didn’t have it. People wanted it and I said no and we didn’t give it to them. The current version of the app has the weight, as you said it’s not the most immediately visible thing, you have to dig for it a little bit. But it also doesn’t give you your [00:23:00] weight today, it gives you the average of the first ten days that you used the Shapa scale and it gives you the average of the last ten days. So you get a sense of what your weight is because sometimes people would ask you and say how much do you weigh and you don’t want to say I’m green. I was trending toward red but, you have to have a language for this so we are giving this to [00:23:30] people, but we’re doing it as the average of the last ten days.

Dan Pardi: I like that, I think giving people an average makes sense if you just happen to step on it once a week and you’re on a day where you’re holding a little bit more water it could make it seem like a good week was a bad week. So trends are good. Well Dan I know our time is short here today, but thank you so much for spending some time with us. It’s a really interesting concept and I wish you all the best success with it.

Dan Ariely: Thank you very much, I appreciate it.

Kendall Kendrick: [00:24:00] Thanks for listening and come visit us soon at humanos.me.