Modeling and Human-in-the-Loop Simulation

Human-in-the-loop (HITL) simulations enable safe, effective, and immersive engagement in complex, safety-critical domains. This chapter explores the foundational role of HITL solutions, grounded in systems thinking and sociotechnical integration. It introduces a structured categorization across live, virtual, constructive, and replicated simulation types, extending into integrated and blended solution spaces. Model fidelity, its critical relationship to human sensory perception, and experiential learning are central to the discussion. An HITL simulation fidelity framework is proposed, linking model abstraction to human senses to guide purposeful designs that support mental model development through right situational awareness (SA). The chapter also addresses the phenomenon of emergence, highlighting the benefits of aligned model interactions and the risks of negative outcomes when combining mismatched abstractions. Through illustrative examples, the chapter demonstrates how fidelity mismatches can lead to degraded user experience and ineffective outcomes. Ultimately, the chapter advocates for a systems-engineering approach to HITL simulation design – balancing technological capability with human-centred fidelity requirements – to enhance readiness, decision-making, and performance in complex operational environments.