Accuracy and precision of visual and auditory stimulus presentation in virtual reality in Python 2 and 3 environments for human behavior research

Abstract

Virtual reality (VR) is a new methodology for behavioral studies. In such studies, the millisecond accuracy and precision of stimulus presentation are critical for data replicability. Recently, Python, which is a widely used programming language for scientific research, has contributed to reliable accuracy and precision in experimental control. However, little is known about whether modern VR environments have millisecond accuracy and precision for stimulus presentation, since most standard methods in laboratory studies are not optimized for VR environments. The purpose of this study was to systematically evaluate the accuracy and precision of visual and auditory stimuli generated in modern VR head-mounted displays (HMDs) from HTC and Oculus using Python 2 and 3. We used the newest Python tools for VR and Black Box Toolkit to measure the actual time lag and jitter. The results showed that there was an 18-ms time lag for visual stimulus in both HMDs. For the auditory stimulus, the time lag varied between 40 and 60 ms, depending on the HMD. The jitters of those time lags were 1 ms for visual stimulus and 4 ms for auditory stimulus, which are sufficiently low for general experiments. These time lags were robustly equal, even when auditory and visual stimuli were presented simultaneously. Interestingly, all results were perfectly consistent in both Python 2 and 3 environments. Thus, the present study will help establish a more reliable stimulus control for psychological and neuroscientific research controlled by Python environments.

Multiple representations of the body schema for the same body part

“…Apparatus and Stimuli. Participants placed their right hand on a table and wore an HMD that displayed visual stimuli in stereoscopic 3D (76). A transparent board was placed over the hand, resting on two blocks (8 cm in height).…”

PTVR – A software in Python to make virtual reality experiments easier to build and more reproducible

“…Data on temporal accuracy for VR headsets are not only scarcer ( Chénéchal & Goldman, 2018 ; Tachibana & Matsumiya, 2021 ; Wiesing, Fink, & Weidner, 2020 ) but also difficult to interpret, as some studies programmed their experiments directly in the Unity or Unreal engines, whereas others used commercial software programs. However, it seems that temporal accuracy with VR headsets is not as good as with CRT monitors.…”

Temporal precision and accuracy of audio-visual stimuli in mixed reality systems

“…Furthermore, when very short auditory and visual stimuli are presented, it is essential for researchers to ensure that their system is capable of delivering such short stimuli. For example, Tachibana and Matsumiya demonstrated that certain systems may not be able to play auditory and visual stimuli with a duration of 22.22 ms or shorter at all [ 24 ]. The accuracy of such short stimuli depends on the frame rate and display refresh rate set by the running software program.…”

“…Their results showed that, while stimulus duration was highly accurate, built-in timing procedures suffered from variable reaction times and inaccurate stimulus onsets. In another study, Tachibana and Matsumiya evaluated the accuracy and precision of visual and auditory stimuli generated in VR head-mounted displays (HMDs) from HTC and Oculus using Vizard on both Python 2 and 3 [ 24 ]. They found an 18 ms time lag for visual stimuli and a 40 − 60 ms time lag for auditory stimuli, with low jitter in the order of 1 ms for visual and 4 ms for auditory.…”