An introduction to the development of visual perception

Subjects Description Does the world appear the same to everyone? Does what we know determine what we see? Why do we see the world as we do?

An introduction to the development of visual perception

Vision provides information about our environment without the need for proximity involved in taste, touch and smell. Vision has an overriding importance in every aspect of our day-to day-lives.

Subject Different brain areas, as well as different processes of perception, are responsible for particular visual functions, such as perception of movement, colour and depth. There are even specific brain regions that deal only with facial recognition or biological i.

Localized brain damage affecting these regions can lead to specific disorders, such as prosopagnosia, in which the ability to recognize faces is lost, while object recognition is unaffected.

Vision would therefore seem to be a good starting place for studying the functional manifestations of brain development. Problems It is difficult to determine whether changes in visual abilities during development are due to limitations in peripheral structures, such as the eye, lens and muscles, or whether they are due to changes within the brain.

The perceptual capacities of young infants are clearly limited by immaturities in peripheral sensory systems e. What is the major constraint on the development of perception?

Research Context Visual sensitivity is poor in newborn primates and develops gradually to adult levels during the early postnatal years.

Numerous studies of visual development have described this process. Generally, contrast sensitivity and acuity, measured psychophysically, are mature by 5 to 6 years in humans and by 1 year in monkeys. Behavioural measurements show sensitivity and acuity improving together, but electrophysiological measurements suggest that the contrast sensitivity of neural elements may mature considerably sooner.

It has become obvious that visual function includes various aspects that begin and mature at different times and that the visual system includes several cortical and subcortical areaseach with its own role in processing specific aspects of visual information. This has allowed us to establish the onset and maturation of each of these aspects in normal infants, providing age-dependent normative data.

Several recent studies have provided evidence that normal development of vision depends on the integrity of a complex network which includes not only optic radiations and the primary visual cortex but also other cortical and subcortical areas, such as the frontal or temporal lobes or the basal gangliawhich are known to be associated with visual attention and with other aspects of visual function.

In the 70s, Bronson suggested a model for human visual development, in which newborn vision is mainly controlled at a subcortical level, with the cortex starting to mature at about 2 months postnatally. The two streams, morphologically distinct at ganglion cell and lateral geniculate nucleus levels, project to different parts of primary visual cortex, V1, and continue within independent cortical streams to the colour-specific area, V4, and to the motion-selective area, V5.

While the parvocellular-based system is used for form and colour vision, the magnocellular system subserves movement perception and some aspects of stereoscopic vision.

Face perception and processing in early infancy: inborn predispositions and developmental changes

In other words, one system is devoted to deciding what and who we are looking at, and the other one decides the appropriate responses and actions to be made. In the early months of life, the visual system is still developing.

The following information gives indicators of normal visual development in young children from birth to 3 years and the relative brain functional implications. In a premature infant depending on the extent of prematurity: The pupils are not yet able to dilate fully; the curvature of the lens is nearly spherical; the retina especially the macula is not fully developed; the infant is moderately farsighted and has some degree of astigmatism.

An introduction to the development of visual perception

Between 6 and 9 months: Acuity improves rapidly to near mature levels ; the infant "explores" visually examines objects in hands visually and watches activity in surroundings ; can transfer objects from hand to hand and may be interested in geometric patterns. Between 9 months and 1 year: The child can visually spot a small mm object nearby; watches faces and tries to imitate expressions; searches for hidden objects after observing the "hiding"; is visually alert to new people, objects, surroundings; can differentiate between familiar and unfamiliar people; vision motivates and monitors movement toward a desired object.

At years of age: However, further development of brain mechanisms for analyzing complex visual scenes, specific objects and faces will occur later. While basic understanding of the social world is good, further development in the ability to predict the intentions and goals of others will continue to occur.

Retinal tissue is mature; the child can complete a simple form board correctly based on visual memorydo simple puzzles, draw a crude circle and put 2.

It is known that the basic functions of early sensory areas of the cortex have completed their development; nevertheless, the functional development of brain substrates for perception of complex visual scenes takes still longer.

These changes involve continuing myelinization of connections and changes in the density of synapses within the prefrontal cortex.

Visual, Auditory and Speech Perception in Infancy, 1st Edition

Specifically, there is a spurt of synapse growth followed by a period of pruning around the time of puberty. Conclusions The contribution of peripheral system retinal development in the emergence of basic visual functions can only partially explain improvements in visual behaviour, indicating that brain changes are also important.

Turkewitz G, Kenny PA. Limitations on input as a basis for neural organization and perceptual development: Developmental Psychobiology ;15 4: The physical limits of grating visibility. Vision Research ;27 The quantum efficiency of vision.Introduction. A significant part of our cerebral cortex is devoted mainly to visual processing.

Vision provides information about our environment without the need for ashio-midori.com Visual Perception: An Introduction, 3rd Edition - Kindle edition by Nicholas Wade, Mike Swanston.

Download it once and read it on your Kindle device, PC, phones or tablets. Use features like bookmarks, note taking and highlighting while reading Visual Perception: An Introduction, 3rd Edition. The perceptual process is a sequence of steps that begins with the environment and leads to our perception of a stimulus and an action in response to the stimulus.

This process is continual, but you do not spend a great deal of time thinking about the actual process that occurs when you perceive the many stimuli that surround you at any given ashio-midori.com Robert Snowden is a Professor in the School of Psychology, Cardiff University, where his research spans visual perception, attention, and abnormal psychology.

Peter Thompson is Senior Lecturer in Visual Psychophysics in the Department of Psychology, University of York, where his research examines the perception of motion and speed/5(3).

The major problem in visual perception is that what people see is not simply a translation of retinal stimuli (i.e., the image on the retina).

An introduction to the development of visual perception

Thus people interested in perception have long struggled to explain what visual processing does to create what is actually seen. Introduction In this article a framework for the development of integrated visual trends in the development of visual perception, and the functions and development of the visual system.

The focus will be on devel- A Developmental approach: A Framework for the development of an integrated Visual Perception programme Elizabeth Daphne Vlok ashio-midori.com

Introduction to Perception (page 1) - The Mind Project