Longitudinal Human Computer Interaction: A Framework for Stable Cognitive Alignment in Large Language Models

This paper introduces the Longitudinal Human Computer Interaction Framework, a new model for understanding how large language systems develop stable behavioral patterns through extended interaction with a single human user. Traditional HCI research focuses on short term usability and task completion, while AI alignment studies emphasize training time interventions such as fine tuning or reinforcement learning. Longitudinal HCI describes a different phenomenon. A system with fixed parameters can show consistent and predictable behavioral change when it engages with a user who provides long term continuity, ethical constraints, and stable reasoning patterns. The framework explains how repeated interaction guides the model toward specific latent representations, reduces drift, improves contextual inference, and enhances safety in professional environments. These effects do not come from memory storage or parameter updates. They emerge from the human’s continuous input, correction, and moral structure. The paper outlines the mechanisms behind this interaction driven alignment, distinguishes it from traditional techniques, and demonstrates its relevance to clinical medicine and other safety critical fields. Longitudinal HCI builds on the author’s earlier work on the Hudson Recursive Identity System and provides a foundation for future research on user specific stability, latent region convergence, and long horizon AI behavior. The paper offers a structured lens for studying how trustworthy AI systems can develop through enduring human partnership rather than through model retraining.