PUB - Publikationen an der Universität Bielefeld

Multisensory integration and recalibration are two processes by which perception deals with discrepant multisensory signals. In the lab, integration can be probed via the presentation of simultaneous spatially discrepant audio-visual stimuli, i.e. in a spatial ventriloquism paradigm. Recalibration here manifests as an aftereffect bias in unisensory judgements following immediate or long-term exposure to discrepant audio-visual stimuli. Despite many studies exploring the ventriloquism effect (VE) and the immediate aftereffect (VAE), it remains unclear whether the VAE is a direct consequence of the integration of preceding discrepant multisensory signals. We here provide evidence that these two biases are not strictly related. First, we analysed data from ten experiments probing the dependence of each bias on audio-visual discrepancies experienced in multiple preceding trials. This revealed a seven-fold stronger dependence of the VAE on preceding discrepancies compared to the VE. Second, we analysed data from an experiment deviating from the typical trial context in which these biases are probed and found that the VAE can vanish despite the VE being present. We argue that integration may help maintaining a stable percept by reducing immediate sensory discrepancies, whereas recalibration may help maintaining an accurate percept by accounting for consistent discrepancies. Hence, the immediate VAE is not a direct and necessary consequence of the integration of discrepant signals and these two well-studied multisensory response biases can be experimentally dissociated.