With the popularity of immersive virtual reality growing it’s time we looked at the power behind this technology and begin to understand how it affects our sense of self.
Predictive Coding is one of the leading theories explaining what our brain does. This theory claims our brain is a prediction machine 1)Friston, 2006. In order to have good predictions the brain combines things it’s already learnt with new information coming from the senses. This theory explains that some of layers of the brain predict whether a movement is self-generated or stemming from an external source 2)Ishida, Suzuki, & Grandi, 2015; Seth, 2014. This requires the notion of a so-called minimal-self, existing even in primitive life, allowing for differentiation between the organism and the environment 3)Apps & Tsakiris, 2013; Limanowski & Blankenburg, 2013. This minimal-self is also a combination of previous knowledge with new incoming information and has been shown to be flexible and prone to mistakes. A great example is the Rubber Hand Illusion 4)Botvinick & Cohen, 1998. The sight of a rubber hand being touched at the same time as a sensation of touch on a person’s actual hand results in the brain predicting that the rubber hand is part of the body and the minimal-self.
Immersive virtual reality allow for manipulation of the minimal-self by controlling the relationship between the visual information and the proprioceptive information. In VR we can create experiences where what a person sees and feels fit the usual prediction created by the minimal-self model, but we can also create experiences that contradict our normal predictions. Recent research shows that virtual reality has indeed been used to manipulate the minimal-self, for instance, to investigate phenomena such as the rubber hand illusion by creating full body illusions 5)Slater, Spanlang, Sanchez-Vives, & Blanke, 2010, treat body image disorders like anorexia 6)Keizer, van Elburg, Helms, & Dijkerman, 2016, investigate mirror box therapy for amputees 7)Wittkopf & Johnson, 2016 and help heal spinal cord injuries 8)Donati et al., 2016.
When the brain experiences something that does not fit its usual predictions it can do one of several things, it can re-sample the information from the senses. For instance, if what a person sees does not fit what they feel in their proprioceptive sense, the brain can lower one of the senses. This sheds light on the possible reasons for mirror box therapy being effective for chronic pain treatment 9)Wittkopf & Johnson, 2016. Patient’s seeing a different body than what they are used to, might reduce this surprise by decreasing the sampling from their pain receptors. Another option the brain can opt for is updating its predictions or its model, creating a learning effect.
As we have seen VR can indeed change the sense of self. Karuna labs uses this ability in its Virtual Embodiment Training to produce specific immersive VR experiences that change the sense of self, causing the brain to reduce chronic pain sensation and induce rapid learning.
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