Creativity of Vision

Lecture chaired by Geoffrey Catchpole

Professor Richard Gregory

Emeritus Professor of Neuropsychology, University of Bristol

21 October 2004.

He would first consider why vision developed, how it evolved and then became creative, long before human beings emerged. The processes which originally developed to aid survival in a totally alien world eventually became a vehicle for art and thought.

The senses were originally vital for survival- for example, in seeking nutrients and avoiding toxins – and behaviour was based on acceptance and avoidance. We now broadly understand how the eye evolved from that basis. Some skin cells became sensitive to light and evolved into areas containing pits with small holes, which provided sensation of ‘moving shadows’ initially. Later, lens developed which enabled the primitive eye to focus, which in turn eventually led to the production of images. Complex neural pathways were needed in order for such developments to occur. (Professor Gregory provided an illustration of a primitive creature, still extant, which has a single nerve fibre in one optic nerve which connects with several lens at strategic points around its body, thus providing a ‘scanning eye’ - as in a television camera – which was described by the speaker as an ‘evolutionary wonder’.)

Our knowledge of the world, provided through any and all of the senses, is extremely indirect – so creativity is required. The primitive nervous system learned to associate what was directly monitored with what was useful, but also learned what might be useful through further associations, thus providing behaviour, which was varied and flexible. The nervous system then used tools such as learning and ultimately thinking to meet more complex survival requirements. This brought originality, creativity and art. The speaker stated that ‘creativity comes when you lose the tyranny of reflexes and you can associate what is monitored from the external world into other characteristics, ultimately into science, which is really creating associations and generalisations moving across great conceptual jumps’. Thus, we have two ‘worlds’ – that of direct experience and that of concepts (understanding via generalities, e.g. in the concept of ‘triangularity’). So we need to distinguish perceptual and conceptual creativity.

Recent research suggests that we have a primitive ‘dorsal stream’ of neural connections in our brain and a much more sophisticated and distributed ‘ventral stream’ in our cortex, which deals with cognition. Through these we can initiate rapid responses, with little understanding and no ‘consciousness’, but also make associations and plan into the future. Perceptual intelligence will provide recognition, but behaviour results from hypotheses about the causes of the stimuli being received. Creativity is the acceptance of limited information from the sensual stimuli and the production of hypotheses to describe causes and associations prior to initiating behaviour.

To illustrate the process in the realm of art the speaker discussed an illustration of a work by Magritte. He commented that the viewer would be required to be very creative when viewing it, since in the transitions from reality to the image in the painter’s eye, then to the canvas and back to the viewer’s eye and brain, there would be many steps. Knowledge of the nature and furniture of the environment involved would be needed before the patterns made in paint could be seen as a depiction of reality. That knowledge could only be gained through experience of the real world through the senses. Thus, ‘interactivity with objects’ is needed for ‘creativity of vision’, even though in that case the depiction would be recognised as not being reality itself. In the speaker’s words ‘Pictures occur in a strange world between earlier experience and present potentiality’.

Signals entering the brain from different sources, with differing delays, require it to create experience of a stable world. When incompatibilities occur (as with illusions) ‘perceptual fictions’ are created. The speaker provided several examples of visual illusions to illustrate the process. (A hollow mask of the face of Einstein, for example, which was really concave was seen in certain positions as being convex. Other examples exploited the Gestalt principle, when the brain provides a complete whole in place of a viewed partial depiction.)

Professor Gregory concluded his lecture with a summary. Stimuli come from ‘physical reality’ (whose nature is depicted variously over time by scientists) and they produce neural signals which are processed into knowledge. That knowledge provides ‘rules’ for vision (such as perspective) which are tested through behaviour, which indicates adoption if successful, but learning if unsuccessful. The process as a whole, based on all of our senses and our processing of experience, feeds into an ‘hypothesis generator’ which provides our concept of ‘reality’ – ‘a complex of hypotheses about the external world’. He emphasised that ‘Your behaviour ultimately determines how you see and how you think…Knowledge dominates perception’.

A lengthy period of discussion and interchange with the audience followed the lecture.

Perception and sampling

Questioned on ‘perception’ of the lecture room, the speaker stated that the ultimate perception results from the sampling of received stimuli being built into a composite. Studies of eye movements have shown what information is actually being used when perceptions are created, which in turn explains why people differ in their perceptions of an object or situation. Further, he claimed that we can ‘see someone’s intentions’ by observing their eye movements, to note what information they are selecting.

Knowledge versus perception

The domination of knowledge was questioned. If one raises a left hand before a mirror it then appears in the mirror to be a right hand, although one knows that it is not. It was thus suggested that in such a case perception overrides knowledge. The speaker conceded the point, but pointed out the peculiarity of the situation- in unusual situations ‘there is always a war going on between the information from the past and the knowledge of the present’. He added that if knowledge completely dominated perception we could never see anything surprising and never learn anything. Monocular and binocular vision situations were discussed, as were unusual situations such as those on the Moon and upside-down pictures of faces. Much depends upon what expectations are set up when we see something.

Mental organisation

As in an army, where too much information inhibits decision-making, mental organisation is hierarchical – strategy is decided at the top level and tactics below, while the actual operations are carried out by subordinates. Both the primitive and the sophisticated brain systems may be stimulated variously by different experiences, but the processes are little known. Newborn babies show reflex activities in the main, but later a supervisory cortex tends to inhibit reflexes for various more sophisticated activities to be developed. In emergencies, however, reflexes take over, since the supervisory commands take more time to operate. For example, when a loud noise suddenly occurs, blinking takes place. Similarly, it is biologically important for autonomic responses to take place in conditions of danger, love, etc, where physiological changes are monitored as emotions. When no external stimulus is present (as for the blind) it is sometimes possible, as in cases of synaesthesia, for people to have cognitive experiences (such as colours and shapes) through physiological brain connections.

Perception and models

The speaker said that ‘there is evidence of a mental model when you have prediction rather than a simple response’. Before the evolution of animals, he thought, creatures were essentially ‘machines’, but since then their reactions to stimuli include the making of predictions to a greater or lesser extent, so he considered that ‘they are likely to be conscious’. We can respond to represented and symbolic situations as well as actual situations, the speaker argued, but when someone said that he could ‘visualise infinity’, the speaker demurred. Mathematical descriptions, as in cosmology, do not amount to visualisation.

Perception and art

The speaker was asked to consider abstract art. Given the evolutionary background, is abstraction possible? Could creativity resulting from accident be involved? Professor Gregory replied that the brain, as a physical system, can deal with any paradoxes, impossibilities, abstractions, etc, but outside of physics it is also capable of representing, symbolising events and ideas, which is the area of the artist. While artists sometimes try to depict ‘sensations’ rather than ‘models’, he agrees with the late Professor Gombrich that ‘ you can never have the untutored eye’. Experience, knowledge and assumptions always affect what one sees. Art students will, however, ‘see differently’- their brains will have been reconfigured by their learning. Moreover, cultural differences will bring differing perceptions. Some artists will want to set standards- there is a ‘moral’ component to art. He concluded that there are differences between the experiences of seeing something as an object, as a representation and as a work of art - a ‘double reality’ situation, in essence.

G. Catchpole