Alfred Klink voices his appreciation of a book by Steven Pinker

Coming across some arguments for and against stereo binoculars and telescopes for astronomy, brought to mind Steven Pinker’s lucid explanations how stereo vision is more than just seeing the same picture twice. Why would anyone assume the extra expense of duplicating the optical system was warranted, when, as we all know, the distances to most celestial objects are way beyond angular resolution? Well, read on...

The brain is one of Nature’s most complicated structures, and the mind very likely its most closely guarded secret. But their combined influence on life and its progress on Earth is phenomenal. From regulating the basic bodily functions to calculating and predicting future events, it spans motor control, sensory perceptions, language, intelligence and philosophical aspirations.
For centuries people have, in trying to understand the brain’s functions, assigned certain functions of the mind to finite parts of the brain (even named sections accordingly) only to find in time higher levels of interconnections involving seemingly unrelated sectors. And in amongst all this accumulated evolution there arouse a new identity, the mental capacity we label consciousness.
What is consciousness? Is it awareness? Is it free will? Our ability to step back and watch ourselves think? Is it something that only arises with a certain level of complexity, or is it (in primitive form) already present in any system which includes some sort of feedback loop? Any system that senses changes and responds to, reacts to, or compensates for a change? Such as a heater with a thermostat, an automatic door with a limit switch, anti-locking brakes on passenger cars, or James Lovelock’s Gaia concept for mother Earth.. Normally consciousness is not recognized (acknowledged as such) at this level. That is just a machine, we say. And a machine does not know what it is doing, or why it is doing what it is doing. We humans are different! Are we not?
At a time when artificial intelligence is becoming a technological industry, when robots are no longer called dumb, when Big Blue is matching the worlds best chess players, we are still struggling to define intelligence’s basic concepts: How do we think, how do we interpret and store sensory inputs, how indeed form philosophical thoughts, what role does religion play in our thinking, what is this “I think, therefore I AM”? Some call it the last great barrier to the understanding of life, the biggest hurdle, the challenge for the 21st century: Who are we? Who am I? Whatever this new century may bring in other innovations, you can be sure the mind and consciousness will rank high on the agenda.
Steven Pinker is Professor of Psychology and Director of a Centre for Cognitive Neuroscience, and his latest book is called How the Mind Works. “Here Darwin meets Turing”, said one of the commentators, “ is a meeting of the theories of evolution and of computation”. The book makes for good reading. I enjoyed it.
I like for instance the way he talks about the eye, how we see things: “It took civilisation five thousand years of trial and error to represent pictorial perspective on paper, and only during the last hundred years man slowly unravelled, bit by bit, how our eyes enable us to perceive a three dimensional image.” The physicist Charles Wheatstone was the first, in 1838, to draw attention to the phenomena.
Our mind combines two two-dimensional outputs of the retinae with the parallax angle of the left and the right eye at the point of focus. Note, this is not the same as judging distance, which is done by sensing the deformation of the eye’s lens needed for correct focus. If you close one eye you still have a feeling of distance, but no appreciation of depth. You need two images for that. The intricate ‘machinery’ of the brain picks out the minute difference in the two separate pictures from the eyes and relates this information to the known angle of their separation. (The imaginary triangle formed from the apex that you are looking at to the distance between your eyes.) In nature it is of vital importance for survival to extract as much information as possible, as quickly as possible, from what the eyes see. Camouflage of a predator can often only be separated from the natural background by recognizing the predator’s shape as a three dimensional object. This you can only do with stereo vision. Whenever the mind is presented with a picture it immediately searches for information that could suggest three-dimensional depth, such as similar patterns of varying size, or recurring dots spaced differently. In the picture below (from page 232) computer-arranged co-ordinates make letters stand out against the flat surface. See if you can see the message hidden in the picture. (Those pictures are also called Magic Eye pictures.)
A hint: Use the two asterisks shown at the top to let your eyes un-focus. (As if you were looking through the paper). Once you see two pairs of stars, concentrate on the two middle stars until they merge, then let your focus drift into the centre of the picture and watch four lines of large text miraculously rise up from the background. Slowly moving the page away or towards you helps sometimes. I wont tell you what it says, you will know it when you see it.
All but some four percent of people have stereo vision. Most deficiencies can be traced to some childhood problem with one or other of the eyes. Stereo vision is an age-acquired ability. Like many of the sensory and mental faculties such as sight, language syntax etc., the mind must be able to practise it, exercise it, during a critical period in a child’s development to activate and condition the function. History data shows that the window of opportunity for stereo vision is very short. In animals often only days from birth. In humans the stereo vision circuits in the brain are functional at the age of four month and “wired” set by the age of two. Any extended periods of visual handicap during this time can seriously affect stereo vision in later life.
What I find fascinating in this continuing journey of self-discovery is how we gradually recognise the various principles that make us humans tick, make us function the way we do. All this ability to cope with modern life, with technology, our ability to drive a motor car, to sit in front of a computer and type an essay, to appreciate music, is using our brain in a way that could not even have been imagined when it evolved to its present size and shape a million years ago. Isn’t this amazing? Here we have a picture seemingly devoid of any information on a flat page, yet our mind recognises a pattern by applying an artificial third dimension to it, stereo vision, perspective. We are inter-actively re-defining our brain’s functioning as we go along, from stone-age, through bronze-and-iron philosophies to the computer information technology, moulding its capabilities by the environment we create and relate with.

How The Mind Works? Everyone should read the book. It gives hope the human mind will eventually help us meet and understand any challenge Nature presents us with. The brain, and life itself, seem to have an unlimited ability (given the chance) to do so. History teaches us that.