Have you tried purple hat therapy?

Hi,

If you haven’t heard of the term “purple hat therapy”, you might want to add it to your lexicon. Stick with me for a sec while I explain it. 

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Purple hat therapy in pictures

Let’s say you have a medical condition, and the treatment is monthly injections at the doctor’s office:

After a few sessions, the doctor mentions a twist: electrical brain stimulation amplifies the nervous system’s response to the injections. Neat! So you go with it:

Eventually the doctor tells you about the newest treatment: doing the injection and brain stimulator while waving your hand in front of your face, pantomiming to the doctor as if he can’t see you.

Waving your hands around feels ridiculous, a bridge too far, so you stop the treatment and find another doctor.

Where was the line?

The term “purple hat therapy” was coined in 2003 and typically refers to mental health therapy components that add a scientifically-questionable layer to an evidence-based treatment. 

If your psychotherapist asked you to wear a fancy purple hat during therapy because it improves effectiveness, you’d be wary because it’s silly and random, but you might still try it.

Same with waving your hands in front of your face. But you might accept a brain stimulator on your head without question because it seems more likely to help. 

The keyword is seems. How does a patient, short on time and expertise, determine how useful a component of treatment seems? Typically by using heuristics such as how science-y something feels, how confident the clinician is in recommending it, and a variety of other things that aren’t based on randomized, controlled trials.

Even though the extra purple hat treatment layer doesn’t undergo specific, separate testing, it can still become widely adopted when people don’t question whether the extra kinda-cool adjunct treatment actually helps more than the treatment it was added to.

What does this have to do with nutrition and supplements?

A lot.

It’s pretty easy to make a quick buck by selling pseudoscience layered on top of something reasonable. Pseudoscience doesn’t have to look silly. In fact, it can look very legit.

One example is the blood type diet, which was popular in the late 90s and early 2000s. Blood types are real and situationally important, as are lectins in general, which are the mechanistic underpinnings of the blood type diet book. 

Yet there’s no compelling evidence for blood types determining what’s good or bad for you to eat. Even if it sounds really cool … and really simple! Just find out your blood type, and blammo you have a personalized list of what’s healthy for you.

Why does the blood type diet seem to work on occasion? Well, if you look at the foods recommended for each blood type, you’ll notice a lack of ultraprocessed junk food. Reducing junk food is an evidence-based way to improve your health.

Blood types are likely to be a well-meaning (if poorly-informed) purple hat added on to the reasonably healthy dietary options laid out in blood type diets. In this case, the hat isn’t a treatment layer, but a treatment-categorization layer. 

The spiritual successor of this kind of thing: dozens of companies now sell gene-based diet plans, and most if not all of them use weak or overextended evidence to classify which foods are healthy for you personally.

Have you ever tried a purple hat therapy?

I’m reasonably well-informed about science. Yet I’ve tried on a few purple hats over the years. How about you? If you have a notable example, reply to this email with it.

And if you can somehow work “purple hat therapy” into conversation with your friends and family, I’d like to know about your success rate. Maybe you can give me some tips. Let’s just say if I had a nickel for every time I brought up a concept I thought was cool and was instead met with glazed looks, I’d be able to buy an actual purple hat. Maybe I should just start waving my hand in front of my face while I’m talking.

Sincerely,

Kamal Patel

Co-founder, Examine