We Know It When We See It: What the Neurobiology of Vision Tells Us About How We Think

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Release Date: 
March 10, 2020
Basic Books
Reviewed by: 

“presents the awe-inspiring process of how we visually perceive the outside world.”

Readers of this review are looking at words and comprehending them. How many readers though have given thought to how we actually “see” words, scenes and people? Truthfully, prior to reading You Will Know It When You See It by Richard Masland, this reviewer had not given a lot of thought to it either. From even casual investigation, it is rather a remarkable process. This text tells us how it happens through the lens of one of the world’s experts in visual understanding.

The author, a lifelong investigator of vision, tells in a straightforward and relatively simple way what happens between the environment of outside world and how we ultimately perceive it. In doing so he describes many vignettes in his own professional life, as well as in the lives of his worldwide colleagues with whom he has shared this investigatory journey.

Early in the text, he answers the question “Is what we see what is really there?” Surprisingly perhaps, it turns out that the answer is NO. Common sense tells us that a single neuron is unlikely to perceive an entire scene and transmit all the detail to our brain. There are at least a dozen types of cells in the retina of the eye, which perceive shape, color, movement, and dark versus white. These cells create 30 parallel streams of information, each providing one feature of the world we view. This mosaic which can be analogized to the pixels on a computer screen, provide a variety of inputs which the visual centers in the brain collate and organize into what we believe we see.

It is truly awe-inspiring to think of this process in all its complexity. Most of us have never given it a second thought but assume that we are seeing what is there in its entirety when in fact we are seeing a patchwork of items which have been deconstructed in the retina and reconstructed in the brain. Having described the basic process, the author delves into the special features of seeing another person’s face as that perception is crucial to our existence and interpersonal connection.

The text goes into depth about the types of cells, their functions and their synapses. Therefore, this book is not beach reading as there is no way, try as the author might, to totally simplify what is an intensely complex process. The best analogy is to compare his description with looking at New York City from the top of the Empire State Building. We see a web of streets and alleys, buildings, parks and moving objects. Let’s assume though that we can also look through the ground and see the complex system of subway routes at four different levels with each level performing a different function and connecting in different places. This begins to describe what happens in the circuitry between the retina and the visual cortex.

Although it requires attention and concentration to comprehend this visual system, the book presents the awe-inspiring process of how we visually perceive the outside world. Even after reading the text, many of us may revert to the simple assumption that we can see those things outside of our body directly and in their entirety without remembering how this happens. Nonetheless, it is an interesting read to follow the author’s journey of discovery to elucidate our body’s visual system.