How the Brain Knows Where Things Are

That’s the subtitle of a delightful new book by Jennifer Groh, a Professor at the Center for Cognitive Neuroscience at Duke University.

making spaceYou don’t have to wait long for Professor Groh’s first speculation.  She opens with the following statement: “Nine-tenths of your brain power is spent figuring out where things are.  (Actually, I just made that number up.  But it may be true.  Bear with me.)”  That speculation is explained, but you’ll have to read the book to find out how close she comes to defending it.  Professor Groh goes on to make the case that among all our sensory systems, the contribution of vision is uniquely important for the brain’s assembly of a sense of space.  This is consistent with the notion of “building a visual space world”, a learned process elaborated by many optometric authorities, most notably Dr. Al Sutton.


I found myself free associating about vision multiple times while reading though Professor Groh’s concise book, it’s analogies and metaphors deftly making difficult concepts easier to grasp.  Consider the following: “The ability to deduce sound location from the clues of sound timing, loudness, frequency and echoes has to be learned and practiced.  This skill develops over the first few months of life and is continually fine-tuned.  As our heads grow, the separation between our ears increases, so the amount of time it takes a straight leftward sound to reach the right ear after arriving in the left ear increases as well.  Our brains must compensate for these changes during youth, and as we age, most people experience some degree of hearing loss.  If this loss is asymmetric, loudness differences across the two ears will be altered and will require mental adjustment.  Typically hearing loss occurs so gradually that we are not aware of recalibrating to retain an accurate perception of sound location.”


I’ve always been drawn to parallels between the auditory and visual systems, and this book draws on comparisons as well as distinctions between visual, auditory, and somatosensory contributions to our space world.  You can gain some sense of the subjects here by visiting Professor Groh’s publications on the website of her Neural Basis of Perception Laboratory, dedicated to Vision, Hearing, Eye Movements, and the Brain.

3 thoughts on “How the Brain Knows Where Things Are

  1. This is not new to most of us who were priviledged to hear the great Optometric speakers such as Skeffington, etal. We must continue to pass this wisdom on to those who come after us. It is also nice to read of those outside our discipline who support those views.

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