Nobody really likes talking about Diarrhea.  It’s a taboo word we only use in hushed whispers—and only when we truly trust the listener. Claire Chase, on the other hand, doesn’t mind talking dirty. In fact, she’s spent her life’s work mired in it. It’s a good thing too, because her discoveries provide essential context on how to change behaviors. 

Chase has followed the biggest philanthropic players that have spent billions of dollars addressing this disease. We’re talking about acronym agencies that instill confidence like UNICEF, CDC, and WHO. They’re focused on diarrhea because it robs the world of 2.2 million children every single year. That’s more than AIDS, Malaria, and Measles combined.1 Consider this: In America, we lost over two thousand loved ones in the attacks on the World Trade Center. We lose nearly three times that many children to this disease every single day. 

However, this crisis can be averted with the simple behavior of washing your hands. In fact, it’s so potent it can reduce diarrhea by as much as 48%. In the intervention world that’s a Do-It-Yourself Vaccine.

Consider Wagaye Fanta. She sits outside her home in an Ethiopian village surrounded by five children—each growing up in a land mine of potential pathogens. And these invisible hosts “are responsible for a large portion of diarrheal disease” that come through contaminated water, flies on food, or dirty shoes. Which means parents are forced to watch their children suffer through vomiting, knock-you-out nausea, and extreme dehydration. 

One doctor from the CDC explained it this way. “When the knowledge of pupils goes up, the knowledge of their parents go up, and the practices … change and parents’ behavior changes.

As Wagaye explains it, the UNICEF representative “gave [her] advice on properly following up with the children…keeping my house clean and orderly, etc” This informational approach is common. For example, one of the largest hand washing campaigns targeted countries like Senegal, Peru, Tanzania, and Vietnam. “The overarching goal of the project was to stimulate and sustain handwashing with soap behavior at critical times in 5.4 million people.” That’s a staggering shift in daily behavior. But they reported wild success by targeting their audiences through “mass media TV ads, print materials, interpersonal communication (IPC) through household visits or face-to-face group meetings, and community events.”

Other departments are just as bullish on their own success. One doctor from the CDC explained it this way. “When the knowledge of pupils goes up, the knowledge of their parents go up, and the practices … change and parents’ behavior changes.

Millions of dollars spent. Millions of lives saved. 

There’s just one problem. It isn’t true.

Gary Larson, The Far Side

As Chase and her team evaluated these results they learned that multiple agencies were not getting accurate data. Why? First, recipients of these campaigns knew what was expected of them, but cultural expectations make it difficult to be honest when you know you aren’t toeing the line. This isn’t a phenomenon in developing countries alone. A recent investigation uncovered what can only be considered universal hygienic duplicity. They indicated that 99% or respondents in the UK claimed they washed their hands after using the “toilet”. As it turns out the truth is far less sanitary. Because only 32% of the men and 64% of the women actually pumped and scrubbed.2

But Chase also found something even more alarming than the public’s propensity for hygienic duplicity. These social interventions were NOT doing the absolutely essential thing: changing behavior. They brought in a crack squad of behavioral psychologists to design interventions based on decades of research. We’re talking about institutional theories like Azjen’s Theory of Planned Action and the sacred dogma of Locus of Control. They tried to increase motivation by “promoting handwashing as something practiced by good mothers.” They also ensured that soap and water were readily available for each participant. That’s a lot of effort. 

In fact, Chase and her team found, “Knowledge about the correct way to wash hands was found to be high at baseline, and while the intervention led to an increase in knowledge about some of the key times for handwashing, it had little differential effect on already high access to soap and water in households and only modest effects on the self-reported handwashing behavior.” Spreading the message, it was assumed, would stop from spreading the disease. It didn’t. 

The evidence shows that hand washing, like flossing, needs to become habit, rather than something one must think about each time before doing it.

In summary Claire Chase explained that “most people surveyed…knew the importance of handwashing and had some knowledge of when and why they should be washing hands with soap. The evidence shows that hand washing, like flossing, needs to become habit, rather than something one must think about each time before doing it. If not, other priorities get in the way.”

“Like flossing”, she says. 

It just so happens that flossing is where the most impactful methods for behavior change originated.

Change Begins with…Flossing

If you listen to Dr. BJ Fogg long enough you’ll him say “behavior change is easy…” Audacious? Maybe. Just ask a yo-yo dieter, or even Claire Chase and her team. But he’s convincing, not only because he’s spent over twenty years researching habit formation, but because he speaks about the complexity of human behavior in simple, digestible terms. 

BJ, as he is known to his students at Stanfordand in his Behavior Design Lab, is tall and slender and he’s the kind of person you want to teach you about habits. There’s just something sad—or is it ironic—when habit gurus tout life-changing techniques, yet their rotundity confirms they struggle going to the gym. When BJ speaks his voice often sounds strained. Perhaps that’s because for the last 20 years he’s been crying for changes in our approach to habit formation. Traditional academia is steeped in misguided research and unproven methods of behavior change. That’s one of the reasons he advocates an entirely different term: Behavior Design.3

In his NY Times bestselling book, Tiny Habits, BJ simplifies these method by scaling back the desired behavior to something far easier and attaching that activity to a pre-existing routine.  And it started with flossing.

Years ago, Fogg was in a funk. It was “a time when I felt so much stress that I could barely get through each day,” he says. “One morning, after a particularly bad night, I glanced in the mirror and thought to myself, “You know, this could be the day when the wheels totally fall off.” A day of not just setbacks but paralyzing failure.

After he finished brushing his teeth, he picked up the floss and flossed one tooth saying, “Well, even if everything else goes wrong today, I’m not a total failure. At least I flossed one tooth.”

One tooth. That’s it. 

But what BJ did next made the difference. He looked into the mirror and exclaimed “victory.” Leaving him feeling hopeful in an otherwise despondent time in his life. Of course, BJ didn’t stop there. One tooth led to others. Which turned into a healthy habit of flossing after he brushed his teeth. Suddenly, the habit had grown. It’s almost as if his mind needed a simpler jumpstart, and scaling the required cognitive or physical exertion was the rip cord. But BJ is adamant that you must celebrate each win immediately. Even if it’s tiny.

“Simplicity is powerful because when a behavior is easy to do, it doesn’t require lots of motivation.” Fogg says. “Weeding your garden for 2 minutes requires less motivation than weeding for 5 hours. Donating $1 requires less motivation than donating $1000.”

And what of those mother’s who simply knew they should wash their hands but didn’t. BJ calls this the Information Action Fallacy—misguided expectations that merely increasing information will change a person’s behavior.  In a recent email, BJ remarked, “If you make a new habit super easy to do, you won’t need lots of motivation. And without much effort, a habit can take root in your life. No need to fuss much with motivation or willpower…That insight led me to create the Tiny Habits method.”

The Hand Washing Campaigns of the world could learn a lot from BJ. They weren’t asking the wrongs things. They were just asking it in the wrong way. Instead of asking them to always wash their hands, BJ might suggest that after mothers change a diaper they dip their hands in water. That’s it. Of course, every mother will probably do more—eventually leading to a healthy habit of handwashing. But that’s the point. Habit formation builds over time, it isn’t a simple switch. So, if Wagaye and the millions of mothers like her aren’t washing their hands with soap and water; make it easier for them to start. And help thems celebrate the small wins. Because the world knows every mother deserves more celebration.


  1. Liu L, Johnson HL, Cousens S, Perin J, Scott S, Lawn JE, Rudan I, Campbell H, Cibulskis R, Li M, Mathers C, Black RE; Child Health Epidemiology Reference Group of WHO and UNICEF. Global, regional, and national causes of child mortality: an updated systematic analysis for 2010 with time trends since 2000. External Lancet. 2012;379(9832):2151-61.
  2. Why were they so unwilling to admit the truth? Call it the Trump Effect, when in 2016, millions of Americans duped national pollsters because they were embarrassed by their chosen candidate. Who’s going to admit they didn’t wash their hands coming out of the bathroom when the socially desirable answer is far easier to report?
  3. In full disclosure, I have worked with BJ at his Behavior Design Lab on a number of different projects

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