In the popular Chip and Dan Heath book Made to Stick: Why Some Ideas Survive and Others Die [HH07], the brothers argue that once you’ve become an expert in a particular domain, it is nearly impossible to understand what it feels like to not understand that domain.

Think of how you would explain color to a person born without sight or how you would explain sound to a person born without hearing. In a less extreme example, think of a lawyer who can’t give you a clear answer to a legal question without all sorts of abstractions and qualifications.

They call this the curse of knowledge.

Undoubtedly, one of the biggest abusers of the curse of knowledge is us.

Imagine we’re explaining HTML to someone who has never worked with neither it nor any markup language. We start by talking about basic tags, like <p>, <br>, and <strong>. We then explain how content within tags inherits the properties of those tags and that each tag must be closed by adding the same tag with a forward slash inside of it.

After a bunch of head nodding, we move on to a simple bit of HTML:

To us, there’s not that much more to explain. It’s a nice little paragraph with a break return inside of it and a couple words in bold. Excellent! It’s time to speed forward to CSS and browser testing. Maybe we’ll throw in some jQuery selector stuff before lunch!

Consider the vantage point from the eyes of the markup virgins. Here’s what might be running through their minds:

• Why do we write the text inside of the <strong> tags inline when we don’t do the same for <p>?

• Why does the <br> tag have a forward slash at the end instead of the beginning? Where is the counterpart that closes it?

• Can we put tags inside of the <strong> tag? What if we wrapped the word day with a <strong> tag? Does that make it...even stronger?

The HTML sample we gave to our student was fraught with small assumptions that we didn’t even think could amount to any type of questioning. For someone new, every little nuance has to be picked apart. No assumptions, not even the fact that we write some tags inline and some tags with break returns for code readability, can be taken for granted.

So, when you’re teaching a newbie, teach twice as slowly as you would want to. During each step, consider all the silent assumptions you’re making and make it a point to explain those “obvious” things anyway. Ask your student, frequently, if things are making sense.

When you understand the curse of knowledge may be in full effect, you’ll be more aware of the subtle details your student may be missing.