## 4 The Pilot Study
### Method
#### 4.1.2 Procedure and tools  
The experimental procedure involved three phases. In the first phase, the participants were subjected to a pre-test in order to explore their previous experiences with VR. In the second phase of the experiments, participants were involved in a VR video session with a total length of seven minutes. The VR experience had a medium level of immersion since participants could, from their point of view, be partially physically present in the context (which was familiar), and they could decide and respond to the actors, but they could not influence the virtual scene (i.e., the user had a low level of agency). For recording, we used a 4K Ricoh Theta V monoscopic camera to obtain 360\({}^{\circ}\) video and audio. The 360\({}^{\circ}\) videos were watched by wearing a headset (HTC Vive) that could track users' position in space by increasing the level of immersion. After instructions on using the display were provided and the EEG sensors for calmness, engagement, and alertness were positioned, the participants began to see a video that corresponded to one of the six experimental conditions. The video introduced the participant to the virtual environment through a training session, which was appropriately designed to familiarize them with the device and provide him/her with the instructions necessary to interact with actors in the scenes and with the pop-up system used in the scenario. During the training, the participant was shown his \"travel\" kit, which consisted of a metro pass, two metro tickets and four 50-cent coins, which he could have used during his experience. The participants did not have anything else with them. The training scene was followed by an environmental scene that served as the real experimental session, with a duration of about five minutes. In this session, a guiding voice accompanied the participant throughout the route. The participant then entered the heart of the experience and was projected at the entrance of a metro station, where he/she met a hurried friend who informed him/her of a party and invited him/her to come, giving him/her the name of the street. In the following scene, called \"Google Maps,\" the participant met a passerby--a potential helper (ingroup vs. outgroup x businessman/casual/beggar; Figure 1a-c)--who, if asked, could help the participant find his way. Through the pop-up system, participants made a choice to either ask or not ask for help, provided reasons for their choice, and moved on to the next scene. This scene, called \"Ticket Office,\" presented the opposite situation, which was focused mainly on help-giving interactions, and participant encountereda helpee with the same features, for social appearance and type of group, of the first session. Thus, the two confederates, both male, encountered during the virtual experience, had the same features of the assigned experimental condition, even if two different actors interpret them. In the second session, the participant became a potential helper for a confederate passerby (ingroup vs. outgroup x businessman/casual/beggar), who was asking for a change in order to buy a metro ticket. In this case, the participant had more possibilities: provide the helpee with a complete solution (i.e., give the confederate one of the tickets made available to him/her in the kit), provide partial help (i.e., offer to change the confederate's coins), or not provide help. Again, after making a decision in the pop-up system, the participant went on with the scene and arrived at the final scene, the aim of which was to provide a positive message: the helpee in \"Ticket Office\" helped a passerby who had dropped his wallet. Subsequently, the helpee was found to be a friend of the hurried friend who appeared in the first scene. This mutual connection served as a unifying element that led the participant and helpee to the party together.