My daughter has a milk allergy (amongst others). We discovered this after trying to trace down why she was constantly sick, worrying about something more severe. We finally suspected a food allergy. A quick (and dramatic) trip to the doctor confirmed our suspicions.

This was an upheaval in our life. My daughter and I love to bake. With milk. She loves ice cream, cheese, cream cheese, yogurt. Pretty much any milk product.

We’ve turned this into a challenge to work with, finding alternative foods and recipes. For the most part we’ve been successful. We’ve developed a steady habit of checking all ingredients as we go. It’s astonishing how many foods contain milk protein.

But then, I failed

An accident happened. But not just any accident. An accident that could have, and should have, been avoided. Because literally as I was cooking I was talking about confirmation bias:

It is the best approach to assume you are always wrong, when you question something to verify it. Never assume you are right.

I threw the pre-made (fantastic) Trader Joe’s Gnocchi in the boiling water and continued.

Confirmation bias is really dangerous, it leads us into making mistakes with the utmost confidence. I really am trying to take a default I’m wrong stance.

I whipped up a pesto sauce and finished dinner.

As I was cooking, I thought that I did want them to try the gnocchi. I wasn’t expecting them to eat it, they had non-dairy Mac’n’Cheese. I asked myself, “What’s in gnocchi?” I replied, confidently to myself since I’ve made gnocchi from scratch, “Potato, egg, flour and salt… with other spices.” Good, we’re safe.

And an hour after dinner, my daughter emitted the familiar but nearly forgotten cry. She ran into the bathroom and very forcibly released the allergen from her belly. But why!?

She says through the tears, “It was the gnocchi!”

And looking at the package there is the allergen warning: Contains Milk.

I fell to the exact psychological failure I was actively working on. My daughter had to pay the price, but she’s fine now. Next time I succumb to a cognitive bias what will the consequences be?