“Visual experience is dynamic”
I have been reading about and researching vision and visual perception. I am interested in all aspects of vision science, from ophthalmology and optometry to neurology and psychology. I hope to understand more about the many ways vision is processed and how visual perception works.
visual acuity refers to how clearly a person sees but visual perception is how we interpret the surrounding environment. there is much more to vision than images, colours and shapes or distances between objects.
perception is the ability to see, hear, or become aware of something through the senses. it is the organisation, identification and interpretation of sensory information in order to understand the presented information or environment.
in this way, we also use perception to describe the way something is regarded, understood or interpreted.
with visual perception we interpret the surrounding environment using light in the visible spectrum reflected by objects in the environment. rods are the photoreceptors found around the boundary of the retina, they are responsible for twilight vision, picking up low level light (scotopic vision). although fewer in number, cones dominate in the centre of the eye, picking up light and colour, they are responsible for high spatial acuity (photopic vision).
as perception is not a simple translation of retinal stimuli people have long struggled to explain what visual processing does to create what we see.
perceptual inductions are sometimes interpolations based on previously acquired knowledge. typically, they are often derived spontaneously during perception from a given configuration. they differ from logical inferences which are thought operations that add something to the given visual facts by interpreting them.
perceptual forces are assumed real in both realms of existence. as physical and psychological. physicists describe forces as a push or pull on an object. they can be due to phenomena such as gravity, magnetism, or anything that might cause a mass to accelerate. in physics, a force is any interaction that, when un-opposed, will change the motion of an object.
in ‘Art and Visual Perception’, Arnheim describes an interplay of directed tensions that are not added by the viewer but rather are as inherent as size, shape, location or colour. these tensions, because they have magnitude and force, are described as psychological “forces”.
psychologically they exist in the experience of any person looking. as pulls, they meet conditions established by physicists for physical forces. (physically, molecular, gravitational forces are active too. for example – in paper; holding microparticles together). artists create experiences with physical materials.
light rays emanating from the sun or other source, hit an object, are partially absorbed and partly reflected. some reach the lenses of eye and are projected onto its sensitive background, the retina. elementary organisation of visual shape, by small receptor organs is combined by means of ganglion cells. as electrochemical messages travel towards the brain, they are shaped at other stations until a pattern is completed at various levels of visual cortex.
for any spatial relation between objects there is a ‘correct’ distance, established by the eye intuitively. artists are sensitive to this requirement when they arrange pictorial objects in a painting or elements in a sculpture.
within this is an equilibrium or balance, two forces of equal strength pull against each other. we exert a stylistic, psychological or social preference so that all elements are distributed in such a way as to create a visual balance. although not everyone will agree with an individual’s preference, the eye nevertheless has an intuitive sense.
“Vision typically starts when certain electromagnetic waves strike a light-sensitive retina. The visual end product is something else – a perceptual awareness of the location and properties of objects in the environment.”
‘Perception’ edited by Robert Schwartz
there are many conceptual and theoretical problems in the study of vision. there is no doubt that perceptual phenomena exist. we recognise objects essentially alike, as constellations, and group them together to dynamic effect. stroboscopic effects can change the perception of moving parts. with vision and perception there are metaphysical, epistemological and ontological questions.
“What each of us sees is the reality we know”
‘The Frog Who Croaked Blue: Synesthesia and the Mixing of the Senses’, Jamie Ward