"Kluge" is word used by engineers to describe "a clumsy or inelegant solution to a problem." It's a gadget that works but is overly complicated and inefficient and prone to breakdowns. Psychologist Gary Marcus uses this word to describe the human brain.
Marcus cites many experiments in psychology to demonstrate the brain's malfunctions. For instance, if we are told something is true, we tend to see only evidence that proves it and ignore evidence that would disprove it. Similarly people who are told to go room 756 and guess the number of beans in a jar will guess higher than people told to go to room 110. These and other quirks are explained by the physical structure of the brain.
I've been reading books by psychologists recently. You can find my reviews under "Writing" on this blog. One of those books, The Confidence Man by Maria Konnikova, provided some research for The Con Man's Son.