Speaker
Description
The perceived body location arises from the integration of multisensory inputs. However, whether top-down factors can modulate body position perception beyond multisensory integration remains unclear. Here, we investigated whether verbal conditioning could change the perceived body location and whether this effect depends on the presence of visual information (i.e., visual exposure to a virtual hand). Participants, immersed in virtual environment, completed four conditions where verbal information was manipulated: (i) Baseline, with no verbal instructions and no change in hand position; (ii) Placebo Displacement, where participants were told their hand would be displaced, although no shift occurred; (iii) Control Displacement, where participants were informed the hand would move and then return to its original position; (iv) Real Displacement, where participants were told of a displacement and the hand was actually shifted. In each condition, perceived hand position was assessed implicitly, using a body localization task (BLT), and explicitly using a Likert scale. In Experiment 1, participants had no visual feedback (black screen), while in Experiment 2, they observed a misaligned virtual hand before the tasks. We conducted two Bayesian ANOVAs to compare shifts in explicit (question scores) and implicit (BLT estimates) measures across Experiments and Conditions. Results showed that verbal manipulation influenced the explicit perceived position independently of visual exposure, as a shift was observed in the Placebo condition in both experiments. Conversely, the implicit measure was affected only after the visual exposure, suggesting that verbal information is not sufficient alone to modify the implicit perceived position without additional sensory input.
