# Modelling and Measuring Trust in Human-Robot Collaboration
## 3 Materials and Methods
### Experimental Process  
In order to ensure that the experimental phase aligns with the established objectives, it is imperative to define a set of guidelines during execution that endorse the accurate execution of the process. The tasks earmarked for experimentation are delineated below:  
* Participants reception: Participants are briefed about the project and the experimentation, ensuring they are informed about the purpose, the physiological signals that will be collected, and the treatment they will receive. They are assured of data privacy through pseudo-anonymization and told of their right to opt out anytime. Once they consent, they provide demographic data and complete a technology trust survey. They are then familiarized with the experimental setup and equipment to capture psychophysiological signals (see Figure 2). Participants are instructed to minimize movement during the experiment for data quality control.  
* Biocalibration: The biocalibration phase ensures the equipment is accurately tuned to the individuals' varying physiological responses. This adjustment considers that, without context, a specific value cannot conclusively indicate high or low intensity. This phase helps define the participant's normal thresholds in varied states of relaxation and excitement. After equipping the participants with the measuring gear, they perform tasks designed to both stimulate and soothe their signals, thereby minimizing uncontrolled disturbances.
* Familiarization: The familiarization stage aims to ensure that participants completely understand their tasks and possible implications during the experiment. In this phase, participants repetitively interact with the machine to understand its workings, ensuring they can easily express their trust or mistrust. Unlike the experimental stage, they are made aware of the sensor's performance, helping them form trust-based responses. This process also helps them become accustomed to the screens displaying crucial information during the interaction process.
* Experimental process: During the experiment, participants interact with the machine and gauge the sensor's trustworthiness. They are presented with a system state (\"well lubricated\" or \"poorly lubricated\") and the default action matches the system state. They only interact if choosing to disregard the sensor. They are then informed of the real machine state and the result of their decision. This cycle repeats a hundred times with varying patterns unknown to the participants (see Figure 3).  
Figure 3: Sequence of events on a single experimental cycle.  
Figure 2: Participants wearing the measuring devices during the experimental phase.  
* Informal interview: A brief interview follows the experimental phase for each participant to assess their experience, identify disruptions, and understand areas of future improvement. It is especially important for participants presenting anomalies in signal visualization or behaviour. It helps filter data from those negatively affected by conditions like discomfort with measuring instruments or misunderstanding their tasks. This interview also aids in understanding participants' perception of the system's reliability and identifying personal traits influencing their perception.