Anil Seth has recently been experimenting with a new tool in his study of human consciousness: strobe lighting. A powerful strobe lamp, according to Seth, is capable of inducing altered states of consciousness, while allowing him to record brain signals at the same time. “It looks like we’re simulating an altered state of consciousness, but we don’t know for sure yet,” Seth says. “We have to be careful. When you flicker a strobe light at someone you get messy data.”
Seth, the co-director of the University of Sussex’s Sackler Centre for Consciousness Science, has been studying a fundamental scientific problem for most of his career: the question of how consciousness happens. “All my research is geared towards understanding what happens in the brain during conscious perception,” Seth says.
The standard experimental setup of cognitive experiments used to involve seating someone in a dark room, at a desk, and administering a computer-based test. These experiments, although valid, are not what scientists call “ecologically valid” — in other words, they don’t replicate the environment and complexity encountered in real-world experiences. Now, Seth uses various different experimental tools, ranging from strobe lights to psychedelic drugs.
In recent years, Seth has been experimenting with virtual reality. “It’s been a longstanding goal that came about when trying to understand, from a neuroscience perspective, the notion of presence, the question of how and why we typically experience things are being real, as in really existing in the world. When we start asking that question, VR becomes an important experimental tool.”
Seth is using VR to manipulate the way we experience being ourselves, the experience of embodiment and body ownership. “We can manipulate those in very interesting ways using VR, which wouldn’t otherwise be possible,” Seth says. “The potential for VR in neuroscience is enormous and is just getting going. In five years, it’s going to be game changing.”
Here are three examples of how in Seth, with colleague Suzuki, is using virtual reality to get a better understanding of our conscious experiences of the world and of the self.
In this experiment, Seth and postdoc Keisuke Suzuki test something called perceptual presence: do we perceive objects as being there as opposed to perceiving them as images of those same objects? “With a real object I can perceive the back of it even though I can't see it,” Seth said. “I perceive it as an object with a back.” The question, for Seth, is how the brains perceives objects, instead of images. One hypothesis for why this happens is that the brain is predicting how sensory signals would change if one picks an object and moves it around. Using augmented reality, Seth and Suzuki built different categories of virtual odd-shaped objects that don’t behave normally: one of the objects, for instance, always displays the same face to the viewer no matter how much they rotate it; another responds to movement in an unreliable manner.
Using Google Deep Dream algorithms, Seth and Suzuki are investigating what happens in the brain during visual hallucinations akin to psychosis or psychedelic trips. In this example, we see the University of Sussex campus transformed into a trippy hallucination with dog faces everywhere.
The rubber hand illusion is an excellent party trick and a key experiment for understanding the notion of body ownership. In the standard version of the experiment, a fake hand is put on a table in front of the subject, while concealing his real hand behind a piece of cardboard. The other hand and the fake hand are then simultaneously stroked with a paintbrush, resulting in the illusion that the fake hand is actually ours. In Seth’s VR version, a virtual hand can be made to flash in synchrony with the heart beat or change in size and colour, allowing him to explore not only how malleable the experience of body ownership is, but also how people sometimes misperceive their own bodies in cases of body dysmorphia.
For a more... brutal example of how we can come to perceive a rubber hand as our own, watch the video below from the University of Freiburg.