Investigation of human defence responses in a virtual reality environment: an EEG study

A predatory imminence continuum displays the perceived imminence of threat to visualise the risk to the prey. Most human studies have utilised static paradigms that may lack ecological validity and limit the exploration of defensive behaviours. Therefore, the present study investigates Fight/ Flight defence responses and underlying neural correlates using EEG under varying conditions of threat proximity and escape availability using a virtual reality (VR) environment. The experiment consisted of a desktop VR environment, including training and experimental phases (5 conditions). Conditions 1 to 4, except 5, included a threat avatar. The conditions differed based on threat proximity (distal/ proximal) and participant's escapability (escape/no-escape). Twenty trials were presented, with each condition presented 4 times. Participants responded with a Fight/Flight response to the threat, followed by a 10-s rest scene and a 5-s fixation. A significant difference in reaction time was observed, indicating distinction based on threat proximity and escapability. A heightened Fight response was observed across all conditions. This pattern may reflect the absence of consequences associated with defensive actions compared to real-life scenarios. For the electrophysiological analysis, ERP analysis indicated a significant difference in the Late frontal activity at the F1 electrode across all conditions. This may suggest tentative cognitive processing during the period surrounding defensive response (Fight or Flight) selection and execution. Together, the findings indicate that although the lack of consequences may have promoted the Fight response more in the VR scenarios, the neural responses may have shown differences in cognitive processing.