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Seeing is believing Garmt Dijksterhuis The journey starts with a black circle painted on a white wall. It seems so simple, but it leads to deep philosophical questions about reality. When you take a good look at the black circle for some time and then look at the white wall, you’ll see the circle projected onto the wall, but as a negative. The circle now looks whiter than the wall, while the wall around it is a light grey colour. This is an afterimage, the result of chemical processes in the retina. So you see something on the white wall, while only a little while ago you didn’t see anything on it What would happen if you projected a blurred circle onto the wall in the place where you see the afterimage? Now you’ll see a combination of the afterimage and of the light reflecting off the wall. A circle becomes visible, but you don’t know what the source of the circle is. Is the circle on the wall or are you perceiving something thatoriginated in your own retina? If you take another good look at the black circle, you’ll see a sort of light ring around it, like a sort of corona. You’ll also see this with shades of grey. Because of this, grey stripes are rarely seen as a uniform colour. This is a result of processes in the visual cortex. This phenomenon is due to the way in which the nerves are linked behind the retina, by so-called lateral inhibition. It leads to an intensification of contrasts and helps us to perceive differences in light. Because of the so-called Machbands which are produced, grey lines appear which are sometimes curved and have shadows as though they are illuminated by an external light source. What happens if you are shown curved lines of grey paper? Will you see the differences in light from the effects of the shadow, or do you see the result of the lateral inhibition links of your visual nerve cells? We are travelling into the visual cortex, starting in the retina, and travelling via our visual neurons to areas where our memories are also stored. Deeper in the brain there are not only the memories of our own personal history, but also matters which are common to all of us as members of a biological species.Our brain developed through evolution and to an important extent the results of this determine how we perceive things and what we see. It is very difficult to escape from this. For example,it means we are very good at observing faces: we recognise and interpretfaces completely automatically. We also sometimes see faces in figures which are not meant to be faces, a form of pareidolia (seeing a recognisable shape in something which is not intended to be that shape).
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So what happens when you suddenly recognise a shape in a work of art that you’re looking at? Did the artist put it there, or is it a case of pareidolia? When you look at the work of Roland Schimmel you’ll see figures which could be the result of afterimages on your retina, of the lateral inhibition in your visual neurons or of your capacity to see familiar objects everywhere. You no longer know whether you looking at a projected image or whether you’re creating the image yourself. The experience of the work of art takes place at the end of our journey from the retina deeper into the brain. We cannot know exactly where the endpoint of this journey is, but even if we could find this endpoint, you will not find a homunculus there looking at the endpoint of all the neurons to provide you with the experience. It’s possible that the whole journey itself is the experience. You can also simply experience the paintings and projections of Schimmel as a passive viewer, and see them as being beautiful, interesting or different. But this will soon change when you become aware that you are possibly seeing more than what the artist put into the work of art himself. Does this creative process take place completely automatically, prompted by our brain, or do we play an active role in this ourselves? Can we see something without interpreting it? Do we actually know whether there is an objective reality which we can perceive with our eyes, and can we really ever know this? The subjective experience is possibly the greatest enigma in psychology. It touches on some of the greatest questions in philosophy, such as those related to “consciousness”, the “self” and the “other mind” problem. The last question concerns the fact that you can only assume that other people exist and function in more or less the same way that you do yourself, but that you can never know what the experiences of other people are like. You can’t everknow whether they have any experiences. If you’re not even entirely in control of your own perceptions, how can you know about the perceptions of others? If there is one thing Schimmel’s work does, it is to make you think about reality and about the place that you have in it. To doubt “objective reality”, and to become aware that this depends to a large extent on your own position in it, brings you closer to that reality. Recognising the fact that this reality does not only originate from your own eyes, your own brain, but also from your personal history, the culture in which you grew up, your biology and your psychology, is a step in the direction of recognising therealities of others. Perhaps it is too much to expect that this will lead to greater mutual understanding and tolerance, but it certainly won’t lead to less. Perhaps even good and evil are no longer absolutes, but can start to depend on the context.
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We started our journeywith a scientific description of the phenomena which Schimmel’s art evokes. Doubting theobjective reality of these phenomena also leads to doubts about the same scientific description of those phenomena. Doubt lies at the source of thought, without doubt there are no choices, no regrets and no possibilities. At the same time, doubt is also the source of science, for doubt leads you to investigate things. In this way we keep going round in the circle we started with, in which we create a reality, doubt it, investigate it, adjust our ideas and see a new reality. Garmt Dijksterhuis, affiliated professor of Sensory and Consumer Science at the Universityof Copenhagen. Garmt studied psychologyand did a PhD in Data Theory. His main area of research is the psychology of perception.