مریم عباسی سورشجانی

Most studies on placebo mechanisms rely on Expectancy Theory, which suggests that conceptual expectations can bring about physiological change. However, the exact processes underlying this effect remain unclear. Perceptual Symbol Systems (PSS) Theory, grounded in Embodied Cognition Theory, offers a more specific explanation: mental representations grounded in sensory-motor systems may directly evoke bodily responses. This study tested whether embodied primes, based on PSS Theory, elicit stronger placebo responses than traditional expectancy-based suggestions. Using a within-subjects design, 71 university students underwent a cold pressure task under three conditions: (1) verbal suggestion of an analgesic cream, (2) visual priming with a photo of a person looking upward, and (3) combined visual-motor priming, where participants also looked upward themselves. The placebo response was measured by changes in pain intensity and heart rate. Results showed that both embodied conditions (visual and visual-motor priming) produced stronger placebo responses than the verbal suggestion condition, as indicated by lower pain intensity and reduced heart rate (F(2,140)=5.83; p<.01). However, the difference between the two embodied conditions was not statistically significant in terms of pain ratings. Notably, visual-motor priming led to a greater reduction in heart rate than visual priming alone (F(6,330)=1.99; p=.06), suggesting a subtle additive effect of motor engagement. These findings support the role of unconscious embodied processes—specifically, perceptual and motor representations—in modulating placebo responses. They offer a promising direction for understanding how non-verbal bodily cues may influence the complex perception of pain.

Equanimity, as a critical feature of well-being can be strengthened and Virtual reality (VR) can be employed to cultivate this capacity. No previous study has directly investigated the impact of different equanimity practices within VR and compared people’s preferences for different practices. This study was conducted to explore whether practicing equanimity within three VR scenarios can increase mind-body calmness. Three VR scenarios (<10 min) were developed. A within-subject study (n=75) was designed to assess impact of these practices in improving calmness indices. Participants were exposed to VR practice sessions combining sound of a teacher and three animation environments including Mountain, Ocean, and Sky facing with changes during a year or day. Participants’ experience of each session was assessed using heart rate variability (HRV), respiratory rate, and self-reported ratings. Subjective state anxiety was also assessed at baseline and after the end of three VR sessions. Physiological indices were improved in Ocean practice compared to baseline and two other practices. Results showed that physiological indices during practices were correlated with self-reports of mindfulness, self-knowledge, and interoceptive awareness (p<.05). A significant reduction was observed in self-reported assessment of state anxiety. Generally, VR practices of equanimity were shown to induce mind-body calmness.