Demand characteristics challenge effects in embodiment and presence

Abstract

The sensations to own and control a body as well as being located in a body describe the relation between ourselves and our body, termed embodiment. Embodiment plays a central role in our everyday actions. However, its assessment is challenging. Recent findings suggest that measures on embodiment are confounded by demand characteristics and suggestibility. To investigate the impact of demand characteristics on embodiment and presence, we compared results from an online experiment measuring participants’ expectations, to the same experiment in virtual reality (VR). In the online experiment, participants watched a video of a participant performing the VR experiment. In the VR experiment, participants performed a soap-bubble-kicking task, which allowed the feelings of embodiment and presence to arise. We manipulated temporo-spatial movement synchrony (Movement: synchronous, asynchronous) and avatar visibility (Visibility: visible, invisible). In addition, we assessed participants’ suggestibility with exercises. The introduced manipulations influenced the ratings in both experiments similarly. Embodiment ratings were additionally affected by suggestibility. Altogether, our results show that participants were aware of the research hypotheses, which indicates that demand characteristics confound embodiment and presence research alike. Overcoming challenges of demand characteristics is crucial to correctly interpret scientific results and to translate these results into applied settings.

Phantom touch illusion, an unexpected phenomenological effect of tactile gating in the absence of tactile stimulation

“…It was recently suggested [9, 20, 21] that embodiment illusions such as the rubber hand may be prone to the influence of demand characteristics of the experimental conditions and phenomenological traits such as suggestibility or phenomenological control. In the case of our experiment, we minimized this confound as we did not provide subjects with any cues about what (especially what touch quality) they should expect and all subjects who had PTI expressed surprise when they felt it.…”

The robot eyes don't have it. The presence of eyes on collaborative robots yields marginally higher user trust but lower performance

“…Moreover, the disparity between subjective and objective measures suggests that in assessing HRC, the latter may be more informative about the user's actual emotional and cognitive state, as suggested by several authors [ [30] , [42] , [55] ]. Subjective measures of acceptability and trust might be prone to confounds, as they might be driven, for example, by experimental demand characteristics, an often-overlooked effect [ 56 , 57 ]. The presence of demand characteristics could at least partially explain the different (or context-dependent) findings in studies looking at anthropomorphism in HRC but needs to be studied further.…”

Phantom touch illusion, an unexpected phenomenological effect of tactile gating in the absence of tactile stimulation

“…It was recently suggested 10 , 22 , 23 that embodiment illusions such as the rubber hand may be prone to the influence of demand characteristics of the experimental conditions and phenomenological traits such as suggestibility or phenomenological control. In the case of our experiment, we minimized this confound as we did not provide subjects with any cues about what (especially what touch quality) they should expect and all subjects who had PTI expressed surprise when they felt it.…”