Customer Reviews

The Vision Revolution: How the Latest Research Overturns Everything We Thought We Knew About Human Vision

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If you were to do nothing more than glance at the chapter names, you would consider this book to be a collection of occult dung powder. Old, stale, and reworked so often that it is dried up. The chapter titles are:

*) Color telepathy
*) X-ray vision
*) Future-seeing
*) Spirit-reading

However, that first impression would be a significantly wrong impression, Changizi has written such a fascinating and scientifically sound book that it remains interesting, even when you disagree with his conclusions.
The chapter "Color telepathy" describes how humans are often able to "read" a person's thoughts and diagnose the state of their health by interpreting slight changes in skin color due to the level of oxygenation in the blood. In this area, his reasoning is sound and Changizi points out that colorblind doctors have been demonstrated to be at a significant disadvantage when attempting to visually diagnose a patient. Where his reasoning breaks down is when he argues that Homo sapiens evolutionarily acquired color vision so that they could use changes in skin color to learn what other people were thinking. In my opinion, this position is untenable.
In general, predators try to blend into the environment as much as possible so that they can get as close as possible before they move in for the kill. Having an acute sense of color vision would allow the relatively defenseless human to spot the stalking predator much earlier than if they were colorblind. Although Changizi's position has some merit, the value of color vision in spotting predators is a much stronger argument for it being evolutionarily selected.
The chapter "X-ray vision" has nothing like the powers of Superman to see through solid objects, the point is quite different. In this context x-ray vision is a consequence of having two eyes with some distance of separation between them, allowing for the brain to receive two offset images. A consequence is that if a sufficiently slim object obstructs your view, while one eye may not be able to see a segment of the visual field, the other eye can, allowing you to "see through" the object. Changizi also convincingly argues why humans and other creatures evolutionarily kept both eyes pointing forward, gaining stereovision when looking forward while losing some ability to see behind them.
Chapter 3, "Future-seeing" is not ESP-style precognition but the processing similar to what we do when we catch a ball. As we prepare for the catch, our minds generate a prediction where the ball will be when it arrives, in other words we must compute the future position of the object. Several years ago, I read a book about baseball where it was stated that when a baseball is pitched at 90 miles per hour, it is physically impossible for the human eye to follow the trajectory for the last several feet. To hit the ball the batter must compute the best estimate as to where the ball will be when it crosses home plate.
In chapter four, "Spirit-reading", the author describes the role of written language, how it was developed and how it is used by the dead or otherwise distant to communicate detailed information to others. Once again, Changizi's analysis is sound; his description of minimal strokes and more complex ideograms as methods of communication was easy to follow and convincing.
It is clear that Changizi is an expert on the concept of how humans use vision to understand their literal place in the world and cope with the dynamic nature of their environment. As optical illusions demonstrate, human vision is a very complex apparatus and in this book Changizi clarifies a great deal in language that is accessible to everyone.

How many people take the time to ponder how we humans, and our animal confreres, perceive the world through vision? It seems that theoretical neurobiologists do. Why do we see in colour? Why are our eyes in front of our heads while some animals have theirs on the sides? Why are we tricked into seeing optical illusions in certain pictures? These are some of the questions which the author tries to answer in this fascinating book. His views are certainly new compared to what many of us may have been taught in school. Yet, once the author has presented his arguments and his evidence, one must admit that, in each case, he has a point. Each of the book's four chapters begins with the basics of its subject matter and progresses from there. Arguments are eventually presented as well as supporting data. Finally, detailed theoretical views are formulated which, for me anyway, required more head-scratching.

The writing style is certainly quite authoritative, friendly, generally clear and even rather lively. Regarding accessibility, as noted above, I found the chapters quite readable but becoming progressively more complex near the ends. Overall, I learned quite a bit from this book. I was also quite surprised at much of the information presented. I think that this book can be of much value to anyone with an interest in how the eye-brain system works and why it works the way it does.

Human brain has picked, in terms of senses, vision to be its favorite - if you consider the number of neurons connected. Perhaps it is the complexity of image processing that requires such tight coupling or perhaps the evolutionary trends on this lane determined that vision could be the deciding factor in spotting opportunities and danger, getting killed or staying alive. Or perhaps both evolutionary and computational needs converge at the eye-brain integration.

I wish the font of the book (printed edition) was better and was more evenly spaced -which would have made for a better reading experience. Also, the author would have reached a lot more mainstream audience by making the style more conversational - as he does in some sections later in the book (see "My Supercomputer Is Running Slowly" in the "Future-Seeing" chapter) but not early enough. Such changes would have catapulted this book to the "Freakanomics - Outliers" level. These, though, are relatively minor points when you think about the expanse of topics presented in this book and great care given to the color pictures, photographs, charts and other artifacts.

This book is both interesting and educational and provides an optimistic note in the realm of vision research, especially for anyone frustrated with funding cutbacks in such research areas. There are many practical applications that can be drawn from this book and the work highlighted and recommend this book highly.

Mark Changizi's application of evolutionary biology to the analysis of vision is brilliant and provocative. As an art historian, I am particularly interested in the chapters on "Color Telepathy" and "Spirit-Reading." Of course, color is a central concern in art history, but I was also fascinated by Changizi's argument for the centrality of flesh color to our perception of color in general. It recalls a passage from the Romantic critic William Hazlitt's essay, "On Gusto," about the variegated flesh color in Titian. Analyzing flesh color in real life, Changizi points out how much it changes from moment to moment, depending on blood, oxygenation level, and emotional states, notwithstanding the fixed amount of pigmentation.

His discussion of contours and combinations of contours as models for written signs is equally fascinating. Here, he sets off speculation about two issues. Is the basic repertory of signs for contours related in any way to the neural wiring of the retina and the brain, which preferentially recognizes certain shapes and alignments: horizontals, verticals, diagonals (as per the pioneering research of David Hubell & Margaret Livingstone)? And could this "machine code," so to speak, of vision be related to abstract forms in art? This last question is of particular interest in relation to Cubism and abstract painting. Perhaps their basic vocabulary is in some way related to the "natural" structure of vision.

A book that constantly provokes new reflections, not just about vision, but about life and culture.

Changizi is undoubtedly a genius, and he writes well, being particularly adept at analogies. Still, Changizi is detailing all the evidence for his conclusions, and some of it is not very interesting.

The most unintuitive conclusion is that our eyes have evolved to detect small variations in flesh color. Yet Changizi is very convincing, particularly because of Figures 14 and 15, which show that 2 of our color cones detect almost the same wavelengths, specifically the wavelengths needed for detecting small variations in flesh color! It is not clear whether this adaptation is primarily for detecting illness, or a person's true emotion, but I would have to go with the latter, and therefore this finding supports those evolutionists who emphasize social interaction as a primary driver in human evolution.

Other than the fact that this book is so easy to understand, I also love that Changizi focuses on the question "why?" rather than "how?" when discussing the mysteries of our eyes. At some point in our lives, we find ourselves wondering why they do this, and why they do that, and hardly ever gaining insight into the truth. The Vision Revolution is engaging and "eye-opening" for anyone interested in the science of our eyes. I completely recommend this book one hundred percent!

This book is informative and engaging, even for a non-scientist. It provides a new appreciation for vision, as it focuses on why we see what we do, rather than how. Filled with drawings and examples, as well as clear and interesting descriptions, this book is easy to follow. You will love it!

An easy to read book for the scientist or lay reader.It informs and encourages us to speculate on human perception evolution with very
interesting illustrations.

Changizi has a light & amusing style, so that one might at first, undervalue him. But noting the citations & reference, plus doing the exercises he mentions, show one that the eye-ball is even more magical than one has ever imagined.

lots of important new ideas here make this definitely worth reading. however, it doesn't "overturn everything" we know about human perception and this author along with a lot of other "new" psychologists would benefit from a more thorough study of what has been known and remains true. in this case i will mention perception of the neutral density spectrum (black-grey-white) as particularly uninformed, though even here there are contributions - just not the revolutionary and "overturning" sort the author hypes. believe it or not, in the early 20th century, by the time i graduated in 1968, perception psychology had already solved a great many mysteries and those solutions stand up quite well because the studies were well and elegantly designed and done. wolfgang koehler and hans wallach, for instance, are among the gestalt psychologists who showed us many things and whose writings are just as interesting as "the latest" stuff.

i think the section on illusions and perception of the future alone is probably reason enough to buy this book.