Mental image
|
|
A mental image is the representation of an idea in a person's mind. The ability to form and recall mental images, to learn about the world from them, and to communicate to others about them is a defining characteristic of the human species.
| Contents |
Introduction
At the most literal level, human consciousness consists entirely of making mental images of the world from the sense data that surrounds us. Light enters through our eyes and sound waves enter through our ears. We touch things to feel them and we put things in our mouth to taste them. We smell airborne particles through our noses. From all of this data our minds make mental images that help us to survive and to reproduce. So much is also true of many other creatures, but the human mind is also able to remember mental images in order to associate them with each other, to compare them to others, and to form useful theories of how the world works based on likely sequences of mental images. Humans are also able to look inward, and to form a mental image of themselves, and of their activities. This introspection is the basis of consciousness.
In many humans, our sense data tends to be dominated by visual data. Many mental images are also strongly visual in nature. It is common in English to use the verb "to see" to mean "to understand". But the same process can also be applied to all other sense data and the mental images we form from them.
Humans also have the ability to synthesize new mental images. We call this faculty our imagination. The range of human activity shows that this can apply not only to visual images, but also to sounds, tastes, and textures. Curiously there are some limitations to this process: few human beings can, for example, imagine new colors or smells. This synthesis is perhaps most strikingly experienced in the form of dreams. In certain forms of sleep, human minds synthesize new mental images at random in curious half-connected sequences. If the dreamer is only lightly asleep, they may become aware of the images, and they may start to experience emotions and sensations connected with them. Thus, we can enjoy a pleasant dream or be frightened by a nightmare. We may remember our dreams when fully awake, although such memories often fade rapidly.
Philosophical ideas about mental images
Mental images are an important topic in classical and modern philosophy, as they are central to the study of knowledge. The urtext is Plato's Republic book VII. Plato uses the metaphor of a prisoner in a cave, bound and unable to move, sitting with his back to a fire and watching the shadows cast on the wall in front of him by people carrying objects behind his back. The objects that they are carrying are representations of real things in the world. The prisoner, explains Socrates, is like a human being making mental images from the sense data that he experiences. To see the "real" world the prisoner would have to make a great effort in order to break his bonds, and to fight his way out of the cave. And when he did so, the bright daylight would dazzle him.
In more recent times, Bishop Berkeley's idea of solipsism has been widely debated. This idea is that the only thing that we can be sure about is our own mental images, and that everything and everyone else in the world is no more than a mental image of our own. This idea is superficially attractive, and has enjoyed a recent revival of interest among those seeking alternatives to mainstream views of the world.
Following modern scientific realist philosophers like Karl Popper and David Deutsch, we can look back to an eighteenth century British writer, Dr. Samuel Johnson, for the case against solipsism. When asked what he thought about solipsism (while out on a walk in Scotland) he is alleged to have replied "I refute it thus!" as he kicked a large rock and his leg rebounded. He point was that the idea that the rock was just another mental image and had no material existence of its own was a poor explanation of the painful sense data he had just experienced.
If we judge the value of our mental images of the world by the quality and quantity of the sense data that they can explain, then the most valuable mental image -- or theory -- that we currently have is that the world has a real independent existence and that humans have successfully evolved by building up and adapting patterns of mental images to explain it. This is the essence of modern scientific thought.
Psychiatric ideas about mental images
Mental images, and particular images from dreams, are the basis for the theories of Sigmund Freud about human behavior. His basic thesis was that our childhood experiences strongly influence the mental images that we make in later life; he believed that humans form mental images that they are not aware of -- our unconscious -- and that these are as important as their conscious images as explanations for human behaviour. Interestingly Freud began his work thinking about Hamlet a play that deals deeply in how mental images affect action.
Psychological ideas about mental images
Much more pragmatically, psychologists working with control systems and other computer systems study mental images in order to help create systems that are easy to use. When users interact with a complex system, like a computer program, a motor car, or a nuclear power station, they form a mental image of how it works. If this mental image is a poor one or has significant differences from the designer's mental image, then the user is more likely to make mistakes.
Further reading
- Plato The Republic, (New CUP translation into English) ISBN 052148443X
- Plato Respublica, (New OUP edition of Greek text) ISBN 0199248494
- David Deutsch The Fabric of Reality, ISBN 0140146903
- Donald Norman The Design of Everyday Things, ISBN 0465067107