Adam O. Bebko’s research while affiliated with York University and other places

Cybersickness is an enduring problem for users of virtual environments. While it is generally assumed that cybersickness is caused by discrepancies in perceived self-motion between the visual and vestibular systems, little is known about the relative contribution of active motion parallax and binocular disparity to the occurrence of cybersickness. We investigated the role of these two depth cues in cybersickness by simulating a roller-coaster ride using a head-mounted display. Participants could see the tracks via a virtual frame placed at the front of the roller-coaster cart. We manipulated the state of the frame, so it behaved like: (1) a window into the virtual scene, (2) a 2D screen, (3) and (4) a window for one of the two depth cues, and a 2D screen for the other. Participants completed the Simulator Sickness Questionnaire before and after the experiment, and verbally reported their level of discomfort at repeated intervals during the ride. Additionally, participants’ electrodermal activity (EDA) was recorded. The results of the questionnaire and the continuous ratings revealed the largest increase in cybersickness when the frame behaved like a window, and least increase when the frame behaved like a 2D screen. Cybersickness scores were at an intermediate level for the conditions where the frame simulated only one depth cue. This suggests that neither active motion parallax nor binocular disparity had a more prominent effect on the severity of cybersickness. The EDA responses increased at about the same rate in all conditions, suggesting that EDA is not necessarily coupled with subjectively experienced cybersickness.

Advances in virtual reality technology have made it a valuable new tool for vision and perception researchers. Coding virtual reality experiments from scratch can be difficult and time-consuming, so researchers rely on software such as Unity game engine to create and edit virtual scenes. However, Unity lacks built-in tools for controlling experiments. Existing third-party add-ins requires complicated scripts to define experiments. This can be difficult and requires advanced coding knowledge, especially for multifactorial experimental designs. In this article, we describe a new free and open-source tool called the BiomotionLab Toolkit for Unity Experiments (bmlTUX) that provides a simple interface for controlling experiments in Unity. In contrast to existing tools, bmlTUX provides a graphical interface to automatically handle combinatorics, counterbalancing, randomization, mixed designs, and blocking of trial order. The toolbox works out-of-the-box since simple experiments can be created with almost no coding. Furthermore, multiple design configurations can be swapped with a drag-and-drop interface allowing researchers to test new configurations iteratively while maintaining the ability to easily revert to previous configurations. Despite its simplicity, bmlTUX remains highly flexible and customizable, catering to coding novices and experts alike.

Advances in virtual reality (VR) technology have made it a valuable new tool for vision and perception researchers since it offers a critical depth cue, active motion parallax. Coding VR experiments from scratch is difficult and time-consuming so researchers rely on software such as Unity game engine to create and edit virtual scenes. However, Unity lacks built-in tools for controlling experiments. Existing third-party add-ins require complicated scripts to define experiments. This can be difficult and requires advanced coding knowledge, especially for multifactorial experimental designs. In this paper, we describe a new free and open-source tool called the BiomotionLab Toolkit for Unity Experiments (BMLtux) that provides a simple interface for controlling experiments in Unity. In contrast to existing tools, BMLtux provides a graphical interface to automatically handle combinatorics, counterbalancing, randomization, mixed designs, and blocking of trial order. The toolbox works “out-of-the-box” since simple experiments can be created with almost no coding. Furthermore, multiple design configurations can be swapped with a drag-and-drop interface allowing researchers to test new configurations iteratively while maintaining the ability to easily revert to previous configurations. Despite its simplicity, BMLtux remains highly flexible and customizable, catering to coding novices and experts alike.

Stereopsis and motion parallax provide depth information, capable of producing more realistic user experiences after being integrated into a flat screen (e.g. immersive virtual reality). Extensive research shows that stereoscopic screens increase realism, while few studies have investigated users' responses to parallax screens without stereopsis. In this study, we examined users' evaluations of screens with only parallax or stereopsis. We found that with only parallax, the mapping between observer motion and viewpoint change should be around 0.6 for a more realistic perceptual experience, and observers were less sensitive to stereoscopic distortions as a result of a different interpupillary distance scaling.

Social learning is important in the acquisition of many primate behaviors, including food acquisition, object use, and sociality. Social learning opportunities are social situations in which social learning could occur and provide a means of studying influences on social learning in observational research. Species-specific characteristics and individual relationships may influence the importance of social learning opportunities for some behaviors over others. We observed eight captive orangutans (Pongo abelii) and five mandrills (Mandrillus sphinx) for >60 h each at the Toronto Zoo to assess intra- and interspecies differences in social learning opportunities. We measured social learning opportunity quality using spatial proximity because this has been associated with high-quality social learning. Both species had similar captive diets and group structure; therefore observed differences were likely due to species and individual differences, rather than captive environment. We found species differences in the frequency of social learning opportunities, their quality, and the associated type of behavior (food vs. social behavior). Orangutans had more high-quality social learning opportunities relating to food behavior than mandrills, and mandrills had more high-quality social learning opportunities relating to social behavior than orangutans. Both species had more high-quality social learning opportunities in mother–infant vs. other dyads. Our results suggest that learning about food behavior may be more important for orangutans and learning about social behavior may be more important for mandrills. Overall, our results suggest that social learning may be constrained/fostered by differences in frequency and quality of social learning opportunities between species and individuals.