The term technical debt is often used to refer to the accumulation of design or implementation choices that later make the software harder and more costly to understand, modify, or extend over time. Technical debt nicely captures that “human understanding” also matters, but the words “technical debt” conjure up the notion that the accrued debt is a property of the code and effort needs to be spent on removing that debt from code.
Cognitive debt, a term gaining traction recently, instead communicates the notion that the debt compounded from going fast lives in the brains of the developers and affects their lived experiences and abilities to “go fast” or to make changes. Even if AI agents produce code that could be easy to understand, the humans involved may have simply lost the plot and may not understand what the program is supposed to do, how their intentions were implemented, or how to possibly change it.
Technical debt lives in the code; cognitive debt lives in developers’ minds.
I’ve experienced this myself on some of my more ambitious vibe-code-adjacent projects. I’ve been experimenting with prompting entire new features into existence without reviewing their implementations and, while it works surprisingly well, I’ve found myself getting lost in my own projects.