IMO controls are genuinely hard in AVE/VR studies. There isn't an obvious "inert" placebo, no light/sound removes immersion, random flashes or audio still affect arousal, and even "wrong" frequencies can entrain.
VR-only controls help, but don't isolate sensory stimulation. That's why many early AVE studies use pre/post designs and treat results as exploratory rather than definitive.
VR-only controls help, but don't isolate sensory stimulation. That's why many early AVE studies use pre/post designs and treat results as exploratory rather than definitive.