VISUAL SYSTEMS AND PERCEPTION

There is something about the ability to interpret the surrounding environment by processing information that is contained in visible light. This resulting perception or vision and its various physiological components are referred to collectively as the visual system. This is the focus of much research in psychology, cognitive science, neuroscience and molecular biology. It is also quite important in reading. How we interpret what we read is fundamental to our visual system. Perception tests and texts abound. The following should not take too long.

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In the next example, the circles appear to rotate when you move your head closer and further away from the screen while looking at the dot in the centre. Our peripheral vision interprets the relative increase or decrease of the image in the retina as rotational motion of the slanted lines

The visual system is the part of the central nervous system which gives organisms the ability to process visual detail, as well as enabling the formation of several non-image photo response functions. It detects and interprets information from visible light to build a representation of the surrounding environment. The visual system carries out a number of complex tasks, including the reception of light and the formation of monocular representations; the build-up of a binocular perception from a pair of two dimensional projections; the identification and categorization of visual objects; assessing distances to and between objects; and guiding body movements in relation to visual objects. The psychological process of visual information is known as visual perception Non-image forming visual functions, independent of visual perception, include the pupillary light reflex (PLR) and circadian photo-entrainment.

The pupillary light reflex is a reflex that controls the diameter of the pupil, in response to the intensity (luminance) of light that falls on the retina of the eye, thereby assisting in adaptation to various levels of darkness and light, in addition to retinal sensitivity. Greater intensity light causes the pupil to become smaller (allowing less light in), whereas lower intensity light causes the pupil to become larger (allowing more light in). Thus, the pupillary light reflex regulates the intensity of light entering the eye.

Entrainment, within the study of chronobiology, occurs when rhythmic physiological or behavioural events match their period and phase to that of an environmental oscillation. A common example is the entrainment of circadian rhythms to the daily light–dark cycle, which ultimately is determined by the Earth's rotation. The term entrainment is justified because the biological rhythms are endogenous: They persist when the organism is isolated from periodic environmental cues. Of the several possible cues, called zeitgebers (German for time-givers, synchronizers), which can contribute to entrainment, bright light is by far the most effective.