Term | Definition |
Stimuli | Are external information in the environment that provokes a physiological or psychological activity or response. |
Sensory receptors | receive & process sensory information in sensory organs (ears, eyes, skin, nose and tongue). Each sense has specialised receptors that detect & respond to only that type of sensory information. |
Reception | process of detecting & responding to incoming sensory information within the sensory organ. |
receptive field | An area of sensitivity within receptor cells. It is the area of space where a receptor can respond to a stimulus. |
transduction | process where (sensory) receptors change the type of energy detected into electrochemical energy |
transmission | Process of sending sensory information as neural impulses to relevant areas of the brain via the thalamus. |
interpretation | process in which incoming sensory information is given meaning so that it can be understood. |
cornea | transparent circular part of the front of the eyeball. Refracts the light entering the eye onto the lens, which then focuses it onto the retina. The cornea contains no blood vessels and is extremely sensitive to pain. |
pupil | the circular opening in the centre of the iris through which light passes into the lens of the eye. The iris controls dilation and constriction of the pupil. |
iris | regulates the amount of light that enters the eye. It forms the colored, visible part of the eye in front of the lens. Light enters through a central opening called the pupil. |
lens | behind the pupil of the eye and enclosed in a thin transparent capsule. It helps to refract incoming light and focus it onto the retina. |
ciliary muscle | responsible for moving the lens for distance vision by expanding and contracting. Flattens the lens for far objects and bulges the lens for close objects. |
retina | a layer of light sensitive tissue located at the back of the eye. Images are focused on photoreceptors on the back of the retina. |
photoreceptors | Rods and cones in the retina work as photorecptors and convert the electromagnetic energy in the form of light to neural impulses (electrochemical energy) |
rods | pure rod vision is black and white but is best for vision when light is dim. the rods are located on the sides of the retina and provides peripheral vision. though the visual detail is low |
cones | provides colour vision, yellow and green are the brightest. vision in daylight or bright is the best. located mainly in the centre of the retina. provides centre vision and high visual detail. |
fovea | Concentrated area of cone receptors on the retina |
optic nerve | carries messages from the eye to the brain. |
blind spot | where the optic nerve meets the eye, no rods or cones. |
visual perception principles | rules that we automatically apply to visual stimuli to assist
organising and interpreting it in consistent, reliable & meaningful ways. |
gestalt principles | unified whole, we see the whole object rather than separate parts. |
closure | We close up, fill in, or ignore gaps and see the object/s as complete. |
camouflage | Camouflage confuses figure-ground and occurs when figure and ground cannot be easily separated but blend together |
figure - ground | The figure (object) stands out against a less prominent ground (background). |
similarity | We tend to see stimuli that are similar in size, shape, colour or form as forming a group. |
proximity | Stimuli that are positioned close together are seen as forming a group. |
depth cues | Are sources of information from the environment (external cues) or from within our body ( internal cues). Our retina has 2D images, but we see 3D. |
depth | Cues that assist our ability to accurately judge: distance, depth, 3D space. |
Binocular depth cue | Require 2 eyes working together. Most useful for objects that are relatively close. |
convergence | When our 2 eyes turn inwards to focus on an object our eye muscles change their tension. The brain detects & interprets depth or distance from this change in tension in the eye muscles. |
retinal disparity | each eye sees everything from different angles. this causes slight difference in the location of the visual images on the retina. slight differences between your two retinas are perceived by the brain as measures of distance, this gives depth perception |
monocular depth cues | Need only one eye, but work in both eyes. |
accommodation | The shape of our lens changes (using ciliary muscles) to focus on near or distant objects. Stretches or elongates for distant objects, bulges for nearby
objects |
pictorial depth cue | Are external cues from the environment. Are named pictorial because artists use them extensively to portray depth and distance on a 2D surface. |
linear perspective | Parallel lines seem to get closer as they recede into the distance. The closer the lines appear to be, the more distant that part of the image is perceived. |
interposition | one object partially obscures another. The partially obscured object is perceived to be further away than the object that obscures it. |
texture gradient | Objects with clear fine detail appear closer. Those lacking detail appear farther away. |
relative size | The object that produces the smallest image on the retina is perceived as being further away. |
height in the visual field | Objects that are located closer to the horizon are perceived as being more distant than objects located further from the horizon. |
Constancy Principles | help us see the world as remaining stable and unchanging despite any changes that may occur to the images cast on the retina. |
brightness constancy | We perceive an object as maintaining its level of brightness in relation to its surroundings despite changes in the amount of light being reflected from the object to the retina. |
size constancy | An object’s actual size remains the same, even though the size of the image that is cast on the retina changes |
shape constancy | an object maintains its shape despite any change to the shape of the image cast on the retina. |
context | The environment or setting in which a perception is made. Assists in quick & accurate interpretation of visual stimulus. |
past experience | We all have different past experiences that set, or predispose us to perceive information in a particular way. |
motivation | Processes within us that create behaviour designed towards achieving a particular goal. We see what we want to see rather than what was actually there. |
emotional state | How we are feeling can influence the way we perceive things. |
culture | Experience with or in a particular culture can influence the way we process and interpret visual information. |
Gustation | taste perception |
taste receptors | detect the chemical molecules that enable taste. Live 10 days & constantly being replaced |
taste buds | on tongue primarily and also in other parts of mouth. 8,000 – 10,000 taste buds. Each bud has 50-150 taste receptors. |