Researchers at the University of Hamburg have discovered a physiological response to virtually rendered humans exhibiting atypical appearances. A study presented Tuesday revealed that exposure to these “virtual agents” (VAs) triggers an immune system response, as indicated by increased levels of secretory immunoglobulin A (slgA) – an antibody measurable in saliva and a marker of immune activity.
The research explored the “uncanny valley” effect, a phenomenon where human-like robots or digital characters can elicit negative reactions if their imperfections create a sense of unease. Scientists hypothesized that subtle deviations from typical human appearance could be interpreted as potential health threats.
In the study, participants interacted with human-like VAs within a virtual environment. Researchers compared the slgA levels following encounters with VAs designed to appear unsettling, optimized and more human-like VAs and simple cartoon VAs. Notably, no increase in slgA was observed after interactions with the latter two groups.
“This suggests that human perception interprets deviating external features, even in virtual representations, as a potential health threat, supporting the pathogen avoidance hypothesis as a possible explanation for the uncanny valley effect” explains Esther Diekhof, head of the Neuroendocrinology working group at the Department of Biology. The body appears to mistakenly perceive these deviations as signs of illness, proactively preparing the immune system.
Interestingly, questionnaires completed by participants revealed no significant differences in their conscious evaluation of the different VA groups. This indicates the immune response operates largely on a subconscious level. “The brain apparently automatically derives a potential danger from the visual information and proactively activates the immune system” says Diekhof. “It’s better to misjudge once than to fail to recognize a health threat.
Similar immune responses have previously been documented when virtual contacts exhibited symptomatic behaviors, such as sneezing. This study, however, focused solely on the impact of subtle differences in physical appearance, particularly around the mouth and eyes.
Researchers designed the experiment to require extended, direct eye contact between participants and the VAs. “The task – to make the strangely appearing virtual contact person smile – made it impossible to avoid them or keep a distance – which would avoid infection” explains Frank Steinicke, head of the Human-Computer Interaction working group at the Department of Informatics.
Results demonstrated a significant correlation between the increase in slgA levels and the degree to which participants felt immersed within the virtual environment, suggesting that a convincingly realistic virtual reality amplifies the perceived health threat posed by strangely appearing VAs.