This document provides an overview of Human Information Processing (HIP) models in human-computer interaction (HCI). It discusses 1) what HIP is as a cognitive model that uses the computer as a metaphor for human cognitive functioning, 2) how HIP models are used in HCI to predict human-computer interaction, focusing on the GOMS model, 3) predictive versus descriptive HIP models and examples of each, 4) alternatives to cognitive models like Activity Theory, and 5) conclusions about increasing complexity in models and the need for multidisciplinary approaches.