Blindsight is the phenomenon in which blind people can interact with their environments even though they can't see it. It could be navigating obstacles or even saying what is in front of them with over 90% accuracy. So how does blindsight work? And how may it help explain consciousness?
To see things, our eyes receive and convert light into information for different parts of the brain to process, until it eventually reaches the primary visual cortex. As this area is damaged in people with blindsight, light picked up by the eyes is not fully processed, and thus does not make it into the person's conscious awareness.
The information does still get processed however, by other parts of the visual system. And this is what essentially allows people with blindsight to carry out tasks that are otherwise unimaginable for those who can't see.
The fact that those with blindsight can 'intuit' their surroundings even without their primary visual cortexes is particularly interesting for researchers.
The phenomenon may mean that things can draw our attention without us even noticing them. For example, one study found that naked pictures of attractive people draw our attention, even when we don't know they're there. Other studies have shown that we can correctly recognize the color of an object even without being aware of it.
Whether or not people with blindsight are conscious of their surroundings, even on some level, however, is hotly debated. While some with the ability report a complete lack of awareness of their surroundings, others report being able to sense 'dark shadows'- signaling some sort of guiding awareness.
Should blindsight not be dependent on awareness, its occurrence may help us understand consciousness. By understanding how the brain can function without awareness, for example, we may be able to work out its evolutionary purpose.
Even if blindsight comes as the result of some level of awareness, however, investigating it may still raise interesting questions. Henry Taylor, a researcher delving further into the topic from the University of Birmingham, says it may help us answer questions such as: 'What is their consciousness actually like?', 'How does it differ from more familiar kinds of consciousness?', and 'Precisely where in the brain does consciousness begin and end?'