Yr 12 VCE Psychology.
Adrienne Graham.
Learning Activity 17: Essay
The Role of Visual Perception Principles
Visual Perception is the selection, organisation, and interpretation of visual sensations
into meaningful objects and events. Visual Perception has a number of key processes,
which are the following: Reception, the capture of visual information; Transduction,
the conversion of the information into a form that can be processed; Transmission,
sending the information from the eye to the brain; Selection, identifying specific
features of a visual stimulus; Organisation, arranging features of the visual stimulus
into a form; and Interpretation, making sense of the visual information. Visual
Perception Principles are ‘rules’ that we automatically apply to visual stimuli to assist
organisation and interpretation of the stimuli in consistent and meaningful ways.
These principles are often used intentionally in artworks, signs, and symbols as they
give the impression of depth and/or distance to the picture. Visual Perception
Principles can be classified into three broad categories which are the following:
Gestalt Principles, they describe how we organise our sensations into perception and
they involve grouping or organising individual parts of a stimulus into whole, or
complete, form; Depth Principles, the ability to view the world in three dimensions,
including making judgements about distance; and Perceptual Constancies, the
tendency to perceive an object as remaining constant (unchanging), despite any
change which may occur to the image cast on the retina.
Gestalt Principles refer to the numerous ways in which we organise the elements in
our visual field by grouping them into the perception of a whole, complete form,
usually in the simplest possible way. There are numerous Gestalt Principles used in
visual perception, which are the following: Figure-ground, Closure, Similarity, and
Proximity. Figure-ground, is when we organise visual information by perceptually
separating important aspects o the visual field into the ‘figure’, which stands out form
the ‘ground’, (the surroundings), by making the object the centre of focus. Signs for
example are used as they can stand out clearly from the background, for example the
‘STOP’ sign. Camouflage occurs when the figure and ground are not easily separated,
but do blend together. Closure, is stimulus and to perceive objects as complete. For
example, with the Telstra logo, we mentally impose a missing vertical stroke to the
letter ‘T’. Closure usually applies with non-verbal information. Similarity is the
tendency to perceive stimuli or parts of a visual stimulus that have similar features,
such as: size, shape, texture, and colour, as belonging together in a unit, group, or
whole. For example, Similarity is applied to uniforms for schools, sports, police, and
the defence force. Proximity (also called nearness) is the tendency to perceive parts of
a visual stimulus that are positioned close together as belonging together in a group.
This is for example apparent, when we look at the Proximity of different symbols
such as the letters of the alphabet or musical notes. In addition to these principles that
influence how we perceive objects, there is another group of principles that help us to
determine where objects are perceptually located.
Depth Perception Cues are sources of information from the environment (external
cues) or from within our body (internal cues) that help us to perceive how far away
objects are (a perception of depth and/or distance). Depth cues are also categorised in
terms of whether they are Binocular (requiring the use of both eyes), or Monocular
(requiring the use of only one eye). Binocular depth cues are those that require the use
of both eyes working together in order to provide information to the brain about depth
and distance. There are two principles that involve Binocular depth cue, which are
Retinal Disparity, the very slight difference ‘disparity’ in the location of the visual
images on the retinas, (due to their slightly different angles of view), which enables us
to make judgements about the distance of an object from the viewer; Convergence,
which involves the brain detecting and interpreting depth or distance (up to about
6metres) from changes in tension in the eye muscles when two eyes turn inwards
(towards the nose) to focus on nearby objects. Monocular depth cues are cues that
require the use of only one eye to provide information to the brain about depth and
distance, but they also operate with both eyes. There are two principles that involve
Monocular depth cues, which are Accommodation, the automatic focusing
mechanism of the lens into the eye to adjust the shape of the lens in response to
differing distances of view from the object; and Pictorial cues, are named because
artists use them extensively to portray depth and distance on a two-dimensional
surface. Pictorial cues involve five principles, such as Linear Perspective, is the
apparent convergence of parallel lines as they recede into the distance. Linear
perspective is a very powerful and familiar depth cue and this is one depth cue that is
lacking in depth in European paintings; Interposition or overlap occurs when one
object partially obscures another, and the partially obscured object is perceived as
further away than the object that obscures it. This is one depth cue that is the most common and is used in still-life paintings; Texture Gradients are the gradual
diminishing of detail that occurs in surfaces as they recede into the distance. For
example, we perceive objects which are in fine detail is clear as being closer and those
that lack detail as being further away; Relative Size is the tendency to visually
perceive the object that produces the largest image on the retinas being closer, and the
object that produces the smallest image on the retina as being further away; Height in
visual field as the location of objects in our visual field, whereby objects that are
located closer to the horizon are being perceived as being more distant than objects
further away from the horizon.
Visual Constancy is the tendency to perceive a visual stimulus as remaining stable
and unchanging despite any changes that may occur to the image cast on the retina.
Size, Shape, Brightness, and Orientation are all aspects of visual constancy. Size
Constancy involves the recognising that an objects actual size remains the same, even
though the size of the image that is cast on the retina changes. The size of the visual
angle is an important consideration in the process of using size constancy; Shape
Constancy is the tendency to perceive an object as maintaining its shape, despite any
changes in the shape of the image cast on the retina; Brightness Constancy is the
tendency to perceive an object as maintaining its level of brightness relative to its
surroundings, despite changes in the amount of light being reflected from the object
onto the retina. An important aspect of brightness constancy is relative light intensity
between an object and its surroundings; and Orientation Constancy is the tendency to
visually perceive the true position of an object in the environment even though the
retinal image of the object maybe at a different orientation. Orientation constancy is
particularly concerned with vertical or ‘upright’ positioning.
As we can tell visual perception are the selection, organisation, and interpretation of
visual sensations. Visual perceptions have a number of key processes, which are
known as Reception, Transduction, Transmission, Selection, Organisation, and
Interpretation. Visual perception principles are the ‘rules’ that we automatically apply
to visual stimuli to assist organisation and interpretation. Visual perception principles
are classified into three broad categories, which are Gestalt Principles, Depth
Principles, and Perceptual Constancies. These principles are often used in artworks,
signs, and symbols as they give us the impression of depth and/or distance to the
picture and/or painting.
By Adrienne Graham 12 AH.