I have just finished this book and it addresses so many of the areas that interest me that I struggle to know where to begin. It also highlights the foolishness of my attempt to give my blog six categories. Two major elements in my life and work (as a sculptor and research psychologist) have no assigned category.

Before I become boringly introspective, I should say that The Mind’s Eye is a fascinating book for both layman and those interested in brain function. There are case studies of real people, full of human detail, telling what happens when parts of the brain cease to work as they should. It also contains a thrilling chapter about the discovery of a brain capacity – stereoscopic vision – in a person who had never had it before. The wonder and delight this brings makes you appreciate the world we live in even more. In addition, Dr Sacks uses his personal diaries to talk us through the complex and alarming experience of his own loss of vision in one eye. One of the revelations to me, is the variation in how much people have, or are able to use, visual imagination. Some people have none to speak of, others have continuous, 3D Technicolor images (as I do), simply by reading a description.

The final chapter, titled The Mind’s Eye, looks at the current state of research into vision and imagery. There are multiple examples from individuals who were born or became blind, as well as input from experts on the brain function behind visual imagery. The whole field of imagination, and its visual substrates, is discussed in an accessible way. A great read.

Now for the introspection:

For many years I was a sculptor and for many years a research psychologist and now I write. Yet the roles are not as separate as they appear in my life. From childhood I have performed thought experiments in the hope of deciphering the actions inside my head, and even now, twenty years since I last made a three-dimensional object, my inner imagination is undoubtedly 3D – very handy for writing. And of course I have a penchant for building brick paths and suchlike.

While I have no synesthesia (cross firing of the senses, e.g. Monday is seen as blue, or the number three smells of vanilla), I have long been convinced that beneath the conscious separation of the senses the brain is more promiscuous. I have been aware (just) of the brain touting problems around at another level. So an engineering problem, which starts life as, perhaps, a set of calculations, with some visual aspects (trying to get, say, a pole to stay upright without a hole or visible means of support) is taken on a tour of unlikely brains areas – hearing, sensory, motor, olfactory, emotional etc – in case these can contribute to the solution – which they sometimes do.

Certainly I belong among the people for whom vivid visual imagery is normal, so from childhood, I can sometimes be confused about whether an image in my head is from a book or a film. I am also baffled and irritated by people who assume that to write about something, you must have lived it. In my experience there are no limits to what you can create inside your own head.

How ‘visual’ is inner imagery? Any activity in the brain is made up of cells firing together. In this sense all imagery is the outcome of sets of switches being on or off – cells a,d,f are on, cells g to z are off etc. Yet if you imagine a complex 3D item in your mind’s eye and turn it round, timing and fMRI scans, show that this actions takes place over natural time as would in the physical world. This suggests there is a spatial element in the brain’s instantiation of inner images…

I’d better stop there.