May 8, 2012 | 1
If Mark Changizi (web, blog, twitter, G+) is right, you don’t have to go see The Avengers in theaters to be impressed by superheroes and their super abilities. Instead, just consider the human eye. That’s right: your visual system contains superhuman powers! X-ray vision? No problem. Color telepathy? Sure. The ability to see into the future? That too. Oh, and communicating with the dead. Sort of. In his book The Vision Revolution, Changizi explains just how it is that you – yes, you – possess such extraordinary capabilities.
Using these four human superpowers as a hook, Changizi brings an evolutionary perspective to several of the most fundamental questions facing vision scientists today. For example, if color and people are both so central to our experience of the world, why do so few languages have color terms explicitly for skin colors? Why do humans have forward facing eyes? (You might think you know the answer to this one, but Changizi has a very different explanation.) How is it that most of us learn to read with relative ease, if reading itself is so new in evolutionary terms that our brains could not have evolved specialized reading mechanisms? (Hint: letters are designed such that they take advantage of our brain’s inherent systems for recognizing objects.)
And why do we so easily fall for visual illusions? Why do visual illusions persist even after we know that our eyes are fooling us? In what is perhaps the greatest triumph of this book, Changizi describes a sort of “periodic table” of visual illusions, which systematically explains why visual illusions don’t represent failures of the visual system, but are rather side-effects of several features built into it.
In answering these questions, Changizi combines evidence from comparative psychology, cognitive neuroscience, anthropology, and linguistics in order to lay out a theoretical perspective for the evolution of the human visual system that could potentially revise much of what we think we know about human vision. While some of his ideas are quite radical (by conventional vision science standards), and many are speculative, I found them generally compelling. Despite the sometimes speculative nature of the ideas, each of them are carefully described, each with a set of empirically testable predictions.
While an important read for vision scientists, it is also extremely accessible to the non-expert reader. Throughout the text, Changizi uses lots of clear, jargon-free examples and do-it-yourself exercises so that you can experience exactly the kinds of visual and cognitive phenomena that he describes. In fact, this book would do well in an undergraduate sensation and perception course. It is refreshing to see a theoretical vision science book take such a broad, sweeping view of visual cognition.
Disclaimer: I received this book as a personal gift from Mark Changizi; this review is entirely unsolicited.