Others have performed similar experiments using slightly different approaches and reporting different results. Some describe partial or gradual adaptation, others wholesale flipping of the visual scene, so it\u2019s still far from clear if there is one human way of relating to the world, or many. To help throw more light on the question, in 2011.\u00a0Degenaar decided to perform his own \u201cfish-out-of-water\u201d experiment, and donned inverting glasses.<\/p>\n
His glasses, which actually look more like goggles, place a right-angled prism in front of each eye, thereby inverting the left and right sides of space. He wore them for four hours a day, on average, for 31 days. To begin with, he saw double and felt nauseous. He would repeatedly fail to grasp an object he could see, finding it impossible to correct for the visual inversion. But the most disturbing aspect of all, he says, was his sense of instability: each time he moved his head, the visual scene rushed past him and he couldn\u2019t track anything in it.<\/p>\n Gradually, he adapted. By day four, he was able to cook a simple meal. By day 13, the visual instability had gone away. Two days after that, he ventured out into the streets of Groningen, where he was a PhD student at the time, armed with a white stick for his own and passer-bys\u2019 protection. On the 30th<\/sup> day something strange happened: he could be looking at a scene, not moving his head or eyes, and he would suddenly be aware of a change in it, even though nothing had moved. A few seconds later it changed back to what it had been. \u201cIt was like a Gestalt switch, like one of those ambiguous images\u2014the duck\/rabbit or Necker cube\u2014that you switch between seeing in different ways,\u201d he says. Being able to switch between two possible ways of seeing the world felt both natural and exhilarating.<\/p>\n There are parallels in his experience to the thought experiment described in the previous post, in which a person\u2019s sensory input is artificially modified when they look at an object of a certain colour. Initially, this person would have a dramatically different colour experience from a neighbour looking at the same object who had not been subjected to the modification. With time, however, her brain would \u201ctune\u201d itself to the new relationship between her eye movements and the resulting signals registered on her retina. Learning that it was the same as before, she would revert to seeing the object as the same colour as before.<\/p>\n Likewise, says Degenaar, with time one adapts to an inverted world and learns to move deftly through it. A conventional way of thinking about perception is to invoke an internal picture of the world that is created in our minds. If that were the case, then that adaptation would require the internal image to flip back to its correct orientation. Degenaar believes something more subtle and complex is happening.<\/p>\n It turns out that we don\u2019t have equal mastery of all the methods at our disposal for visually exploring the world. So for example, turning his head towards an object was difficult when wearing the inverting glasses, but he could move his eyes to it with ease, as long as he kept his head still. According to the sensorimotor theory, perception is about the relationship between movement and the resulting sensory stimulation. The theory predicts that adaptation of visual experience would coincide with the regaining of exploratory skills\u2014which is what happened. Degenaar\u2019s visual experience \u201ccorrected\u201d itself in piecemeal fashion, depending on which exploratory method he was using.<\/p>\n Interestingly, once he had adapted and could again see where things were in relation to himself and to each other, he still felt that he was perceiving the world differently from how he perceived it without the glasses. In other words, though the informational content he was receiving was the same, the quality of the experience\u2014how it felt\u2014was different. The reason, he thinks, is that the way you engage with the world in order to sense it\u2014by moving your head, your eyes and so on\u2014is as much a part of perception as the knowledge it affords. \u201cYour visual experience as a whole is a combination of all these things,\u201d he says.<\/p>\n Degenaar published his findings in the journal Phenomenology and the Cognitive Sciences <\/i>in 2013. Self-experiment is clearly an invaluable tool for probing the phenomenal aspects of perception, but one is a small sample, and he thinks it would be interesting to repeat his experiment in a larger number of volunteers, having them describe their experiences while observers looked for changes in their behaviour that might correspond to stages in their perceptual adaptation.<\/p>\n His ultimate goal, with O\u2019Regan and other members of the FEEL group, is to understand how the brain mediates sensorimotor interactions and underpins perceptual adaptation, rather than generating an internal picture of the world, and also how those relatively low-level sensorimotor interactions relate to abstract thought\u2014the capacity for which is after all one of the things that defines humans. For now, at least, he can say one thing: he knows how the water feels.<\/p>\n","protected":false},"excerpt":{"rendered":" HISTORICALLY, philosophers and scientists have thought about perception in terms of what it tells us about the world\u2014its informational content. But a moment\u2019s reflection reveals that there is more to it than that. \u201cSomething has been left out,\u201d says philosopher … Continue reading ![\"inverting](\"http:\/\/whatfeelingislike.net\/wp-content\/uploads\/2014\/08\/inverting-glass.jpg\")
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