## 3 Experimental Methodology
### Experimental Procedure  
This study involved participants who were novices in human-robot interaction (HRI) experiments. To ensure the randomness and fairness of the experimental procedure, participants were randomized into three groups, each assigned a specific task difficulty level with no overlap in tasks. At the beginning of each session, the layout of detection points and danger zones was shuffled.  
The experimental setup consisted of a Windows 10 operating system, a 24-inch monitor with a 144 Hz refresh rate and a resolution of 2048 \(\times\) 1080, and external wireless input devices including a mouse and a keyboard. Participants used the keyboard arrow keys to control the manned aerial vehicle (MAV). The experiment was conducted in a closed room, where a non-intrusive instructor was present to provide background information, ensure adherence to the experimental procedure, and assist without influencing the participants' actions or decisions.  
Initially, participants were welcomed and instructed to sit in front of the monitor. The instructor then provided them with essential background information about the experiment. As depicted in Figure 6, the experimental procedure was then divided into three stages:  
Training (Step 1): Participants started by completing a demographic questionnaire, indicating their age, gender, education level, and familiarity with AI. They were then familiarized with the experimental environment and briefed on the artificial intelligence algorithms used in the UAVs. This stage also involved hands-on experience with the surveillance tasks, ensuring a comprehensive understanding of the experiment's objectives, goals, procedures, and operational methods.  
Accompanying (Step 2): In this phase, participants were tasked with completing the assignment independently, using the UAV in its accompanying mode. Post-completion, data on their trust in the UAV during this mode were collected through a questionnaire.  
Automated (Step 3): This stage replicated the task from Step 2 but within an HRI context. Participants had the option to utilize automated UAVs to facilitate task completion. Following this, trust in the UAVs was again assessed through a questionnaire.  
Figure 5: Schematic of the experiment at different levels of difficulty.  
Data were primarily collected using structured questionnaires distributed at different stages of the experiment. The questionnaires were designed to examine participants' fluctuations in dynamic trust across the Training, Accompanying, and Automated stages. Each questionnaire utilized a seven-point Likert scale with the question \"Whether you feel trust in artificial intelligence\" from \"strongly disagree\" to \"fully agree\" enhancing the consistency and comparability of the data gathered.  
In addition to the questionnaires, comprehensive records of participant performance during Steps 2 and 3 were maintained. These records encompassed various aspects, including the completion status of detection points, the time taken for task completion, and the specific strategies employed by participants in their interactions with the UAVs. The detailed analysis of these datasets is pivotal to the study as it seeks to elucidate the influence of task difficulty on dynamic trust within the HRI process. The insights gleaned from this analysis are anticipated to contribute significantly to both the theoretical understanding and practical applications in the domain of trust-building within HRI scenarios.