We all rely on our senses to convey veridical information about the world around us, which we call “Reality”. However, distortions of reality in the form of hallucinations or illusions originating from neurological, psychiatric, pharmacological or psychological origins are common. Thus, the sense of reality which is the ability to discriminate between true and false perceptions of the world, is a central criterion for neurological and psychiatric health. Despite the critical role of the sense of reality in our daily life, little is known about how this is formed in the mind and brain. The “UnReal” project proposes a novel theoretical and technological framework to uncover how the sense of Reality the phenomenological, computational and neural processes underlying the Sense of Reality (SoR). The proposed experiments employ a specialized virtual reality environment allowing precise and controlled manipulations of visual reality across different domains (AliceVR). Using this VR platform, we will first test the impact of parametrically manipulating visual reality on judgments of reality in order to build a phenomenological and computational model of SoR (WP1). We will then investigate the neural mechanisms underlying SoR by combining our VR paradigm with high resolution fMRI (WP2). Finally, WP3 will investigate conditions of altered SoR, either of psychiatric origin or pharmacological origin. Here, we will empirically test SoR under conditions of altered reality processing in schizophrenia patients with hallucinations and in a pharmacological model through administration of ketamine in healthy participants. This ambitious project will thus reveal how humans discriminate reality at the phenomenological, cognitive and neural levels. The results will have important implications not only in defining a neurocognitive model of reality in healthy and clinical populations, but also shedding new light upon the fundamental philosophical question of “how do we know what is real?”.
Understanding SoR is also of great importance to society at large. First, SoR is a central benchmark in determining psychiatric and neurological wellbeing. Indeed, symptoms of impaired SoR such as hallucinations, delusions and derealization are a key diagnostic criterion for psychosis and are also present in epilepsy, dementia, Parkinson’s disease and many other conditions. As such, it is critical that we acquire a fuller understanding of how SoR is constructed by the brain and mind, allowing us to provide better diagnostic and therapeutic tools. Furthermore, recent years have brought an unprecedented surge in technological measures mimicking human perceptual experience. Only 120 years ago silent video images began captivating and generating simulated perceptual experiences. Today, consumer grade virtual and augmented reality can create astonishingly immersive experiences 86,159,160 raising ethical, health and societal concerns132,161. A central issue here is the unknown impact of virtual and augmented reality (AR) on the distinction between true percepts and digitally simulated ones. Thus, VR and AR can be considered “cognitively disruptive technology” posing a novel and unique challenge to the SoR. In a world in which the delineation between real and unreal perceptions is becoming more demanding, a strong scientific understanding of the underlying cognitive and neural mechanisms of SoR is essential.
