From entry model human processor in glossary Human–Computer Interaction
The model human processor (MHP) is a cognitive model used by Card, Moran, and Newell in their seminal book The Psychology of Human–Computer Interaction (Lawrence Erlbaum, 1983). It included the keystroke level model (KLM), which broke down low-level input into basic activities such as identifying the target, moving the hand, etc. allowing timings to be estimated.
Used in Chap. 6: page 90