Dynamic Changes of Latency Perception Threshold in Virtual Reality: Behavioral and EEG Evidence

Area of Science:

• Human-Computer Interaction
• Virtual Reality Systems
• Perceptual Psychology

Background:

• End-to-end latency significantly impacts user experience and performance in Virtual Reality (VR) applications like telehealth and virtual education.
• A latency perception threshold (LPT) may exist, below which users do not perceive latency, but its exact value remains undefined.

Purpose of the Study:

• To investigate how interaction strategies and task difficulty affect the latency perception threshold (LPT) in VR.
• To determine the influence of LPT variations on user interactive performance.
• To refine Fitts' law to account for latency effects.

Main Methods:

• Utilized an experimental design based on Fitts' law to measure LPT.
• Varied interaction strategies (speed-focused) and task difficulty.
• Analyzed electroencephalogram (EEG) signals to detect subconscious latency perception.

Main Results:

• The LPT was found to be approximately 130-170 ms.
• Heightened sensitivity to latency was observed with speed-prioritizing strategies and increased task difficulty.
• Latency's effect on interactive performance demonstrated a nonlinear pattern due to the LPT.
• EEG signals detected latency perception even when users were consciously unaware.

Conclusions:

• The LPT influences VR interactive performance, with sensitivity varying based on task demands and strategies.
• A refined Fitts' law model incorporating latency is proposed.
• Subconscious perception of latency via EEG suggests deeper sensitivity than conscious awareness, informing VR system design.