\chapter{Introduction}
\label{ch:intro}

Human-Robot Interaction (HRI) is an essential field of study for understanding how robots should communicate, collaborate, and coexist with people. As researchers work to develop social robots capable of natural interaction, they face a fundamental challenge: how to prototype and evaluate interaction designs before the underlying autonomous systems are fully developed. This chapter introduces the technical and methodological barriers that currently limit Wizard-of-Oz (WoZ) based HRI research, describes a generalized approach to address these challenges, and establishes the research objectives and thesis statement for this work.

\section{Motivation}

To build the social robots of tomorrow, researchers must study how people respond to robot behavior today. That requires interactions that feel real even when autonomy is incomplete. The process of designing and optimizing interactions between human and robot is essential to HRI, a discipline dedicated to ensuring these technologies are safe, effective, and accepted by the public \cite{Bartneck2024}. However, current practices for prototyping these interactions are often hindered by complex technical requirements and inconsistent methodologies.

Social robotics, a subfield of HRI, focuses on robots designed for social interaction with humans, and it poses unique challenges for autonomy. In a typical social robotics interaction, a robot operates autonomously based on pre-programmed behaviors. Because human reactions to robot behaviors are not always predictable, pre-programmed autonomy often fails to respond appropriately to subtle social cues, causing the interaction to degrade.

To overcome this limitation, researchers use the WoZ technique. The name references L. Frank Baum's story \cite{Baum1900}, in which the ``great and powerful'' Oz is revealed to be an ordinary person operating machinery behind a curtain, creating an illusion of magic. In WoZ experiments, the wizard similarly creates an illusion of robot intelligence from behind the scenes. Consider a scenario where a researcher wants to test whether a robot tutor can effectively encourage student subjects during a learning task. Rather than building a complete autonomous system with speech recognition, natural language understanding, and emotion detection, the researcher may use a WoZ setup: a human operator (the ``wizard'') sits in a separate room, observing the interaction through cameras and microphones. When the subject appears frustrated, the wizard makes the robot say an encouraging phrase and perform a supportive gesture. To the subject, the robot appears to be acting autonomously, responding naturally to the subject's emotional state. This methodology allows researchers to rapidly prototype and test interaction designs, gathering valuable data about human responses before investing in the development of complex autonomous capabilities.

Despite its versatility, WoZ research faces two critical challenges. The first is \emph{The Accessibility Problem}: many non-programmers, such as experts in psychology or sociology, may find it challenging to conduct their own studies without engineering support. The second is \emph{The Reproducibility Problem}: the hardware landscape is highly fragmented, and researchers frequently build custom control interfaces for specific robots and experiments. Because these tools are tightly coupled to particular hardware, running the same social interaction script on a different robot platform typically requires rebuilding the implementation from scratch. These tools are rarely shared, making it difficult for a researcher to reproduce the same study across different robot platforms or for other labs to replicate results.

\section{Proposed Approach}

To address the accessibility and reproducibility problems in WoZ-based HRI research, I propose a web-based software framework that integrates three key capabilities. First, the framework must provide an intuitive interface for experiment design that does not require programming expertise, enabling domain experts from psychology, sociology, or other fields to create interaction protocols independently. Second, it must enforce methodological rigor during experiment execution by guiding the wizard through standardized procedures and preventing deviations from the experimental script that could compromise validity. Third, it must be platform-agnostic, meaning the same experiment design can be reused across different robot hardware as technology evolves.

This approach represents a shift from the current paradigm of custom, robot-specific tools toward a unified platform that can serve as shared infrastructure for WoZ-based HRI research. By treating experiment design, execution, and analysis as distinct but integrated phases of a study, such a framework can systematically address both technical barriers and sources of variability that currently limit research quality and reproducibility.

The contributions of this thesis are the design principles of this approach, namely: a hierarchical specification model, an event-driven execution model, and a plugin architecture that decouples experiment logic from robot-specific implementations. Together they form a coherent architecture for WoZ infrastructure that any implementation could adopt. To evaluate the impact of these design principles, I developed a reference implementation called HRIStudio: an open-source, web-based platform built on this architecture and used as the instrument for empirical validation.

\section{Research Objectives}

This thesis builds upon foundational work presented in two prior peer-reviewed publications. Prof. Perrone and I first introduced the conceptual framework for HRIStudio at the 2024 IEEE International Conference on Robot and Human Interactive Communication (RO-MAN) \cite{OConnor2024}, establishing the vision for a collaborative, web-based platform. Subsequently, we published the detailed system architecture and a first prototype at RO-MAN 2025 \cite{OConnor2025}, validating the technical feasibility of web-based robot control. Those publications established our vision and a first prototype. This thesis extends and formalizes our contributions: a set of design principles for WoZ infrastructure that simultaneously address the \textit{Accessibility} and \textit{Reproducibility} Problems, a reference implementation that realizes those principles, and pilot empirical evidence that they produce measurably different outcomes in practice.

The central question this thesis addresses is: \emph{can the right software architecture make Wizard-of-Oz experiments more accessible to non-programmers and more reproducible across participants?} To answer it, I propose a hierarchical, event-driven specification model that separates protocol design from trial execution, enforces action sequences, and logs deviations automatically; implement it as HRIStudio; and evaluate it in a pilot study comparing design fidelity and execution reliability against a representative baseline tool. The goal is not to prove a statistical effect at scale, but to establish directional evidence that the architecture changes what researchers can do and guides them to be consistent in the pursuit of their experimental goals.

\section{Chapter Summary}

This chapter has established the context and objectives for this thesis. I identified two critical challenges facing WoZ-based HRI research. The first is the \emph{Accessibility Problem}: high technical barriers limit participation by non-programmers. The second is the \emph{Reproducibility Problem}: fragmented tooling makes results difficult to replicate across labs. I proposed a web-based framework approach that addresses these challenges through intuitive design interfaces, enforced experimental protocols, and platform-agnostic architecture. Finally, I posed the central research question and described how this thesis addresses it through formal design, a reference implementation, and a pilot validation study.
