The Multifaceted Ganzfeld at the Crossroad Between Visual Perception and Consciousness: Behavioral, Neural and Qualitative Aspects.

Abstract

A Ganzfeld is a homogeneous visual field, devoid of any focal points. Such a stimulus has been used by researchers to study perceptual phenomena in the absence of changes in sensory structure. Others have used it to study altered states of consciousness (ASCs). Until now, these different facets have been studied separately with little attention for the emotional subjective experience. This study aimed to elucidate the perceptual, phenomenal, and emotional experience of the multifaceted Ganzfeld using a multi-method approach combining behavioral (eye-tracking) and neural (electroencephalography; EEG) measures, with qualitative (interviews) and quantitative (questionnaires) assessments. We show that Ganzfeld spaces induce ASCs and offer immersive, full-body experiences, including bodily effects. Our results pertaining to bodily sensations further prompted us to identify a perceptually grounded cognitive processing type with either an inward-directed or externally-directed focus. We also identified the presence of an abstract cognitive processing type characterized by an introspective focus and meditative experiences. At the behavioral level, decays were characterized by decreased eye movements. The lag in reporting decays and the subjective experience of decays point to the notion of mind blanking. At the neural level, we found increased theta activity preceding decays, further hinting at a potential interrelation between perceptual decays and mind blanking. Finally, decays were characterized by more alpha activity, a pattern often associated with attenuated sensory processing and states of reduced external engagement (Jensen & Mazaheri, 2010), such as relaxation. Our findings contribute to a more in-depth understanding of all the components contributing to the rich Ganzfeld experiences.