Sensation
- is a passive process, by which our sensory receptors and sense organs detect & respond to sensory information that stimulates them.
Perception
an active process by which we give meaning to sensory information. Involves interpreting sensations by translating them into information that is meaningful and useful.
Cornea
a transparent, convex-shaped (curved outwards) covering which protects the eye and helps to focus light rays onto the retina at the back of the eye.
aqueous humor
a watery fluid that helps to maintain the shape of the eyeball and provides nutrients and oxygen to the eye, as well as carrying away waste products.
pupil
the adjustable opening in the center of the eye through which light enters
Iris
a ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
Lens
A flexible convex structure right behind the pupilThe role is to focus light on the retina and adjust its shape due to the distance of the object being seen.
Ciliary Muscles
muscles which relax or contract and alter the shape of the lens
Vitreous Humour
a jelly-like substance that helps to maintain the shape of the eyeball and also helps focus light.
Retina
Receives and absorbs light and processes images.
Blind Spot
refers to the fact that there are no photoreceptors on that small area of the retina so light cannot be detected there.
Figure Ground Organisation
When we use figure-ground, we organise visual information by perceptually dividing a visual scene into a 'figure', which stands out from the 'ground', which is its surroundings.
camoflage
- occurs when the figure and ground are not easily separated, but blend.
Closure
the perceptual tendency to mentally 'close up', fill in or ignore gaps in a visual image and perceive objects as complete ('whole').
Similarity
involves the tendency to perceive parts of a visual image that have similar features — such as size, shape, texture or colour — as belonging together in a unit, group or 'whole'.
Proximity
(also called nearness/closeness) is the tendency to perceive parts of a visual image that are positioned close together as belonging together in a group.
Monocular Depth Cues
Accommodation - involves the automatic adjustment of the shape of the lens to focus an object in response to changes in how far away the object is.Pictorial Cues - to create depth and distance on 2D surfaces such as paper and canvas.Linear perspective - the apparent convergence of parallel lines as they recede ('go back') into the distance.Interposition - occurs when one object partially blocks or covers another, and the partially blocked object is perceived as further away than the object that obscures it (and vice versa).Texture gradient - refers to the gradual reduction of detail that occurs in a surface as it recedes into the distance, compared with a surface that is close and perceived in fine detail.Relative Size - refers to the tendency to visually perceive the object that produces the largest image on the retina as being closer and the object that produces the smallest image on the retina as being farther away.Height in Visual Field - refers to the location of objects in our field of vision, whereby objects that are located closer to the horizon are perceived as being more distant than objects located further from the horizon.
Binocular Depth Cues
Convergence - involves the brain detecting and interpreting depth or distance from changes in tension in the eye muscles that occur when the two eyes turn inwards to focus on close objects.Retinal Disparity - refers to the very slight difference in the location of the visual images on the retinas (due to different angles of view), which enables us to make judgments about the depth or distance of an object.
Perceptual Constancies
Size Constancy - involves recognising that an object's actual size remains the same, even though the size of the image it casts on the retina changes.Shape constancy - the tendency to perceive an object as maintaining its shape despite any change in the shape of the image of the object on the retina.Brightness constancy - is the tendency to perceive an object as maintaining its level of brightness about its surroundings, despite changes in the amount of light being reflected from the object on the retina.
Perpectual Sets
often referred to as expectancy because various psychological and social factors create an expectation to perceive something in a particular way.
Perpectual Set 2
Context - refers to the setting or environment in which perception is made\Motivation - refers to internal processes which activate behaviour that we direct towards achieving a particular goal.Emotional state - How we are feeling, and our emotional state, can influence the way we perceive visual information.Past Experience - refers to our personal experiences throughout our lives. This includes everything we have learned intentionally and unintentionally.Culture - refers to the way of life of a particular community or group that sets it apart from other communities and groups.
Rods
- Responds to low levels of light and is responsible for night vision- They are not good at detecting details in an image and aren't involved in colour vision- This explains why everything in the night appears to be shaded of grey and is sensitive to movement- There are 124 million rods per eye- They are numerous to the periphery of the retina and provide us with peripheral vision.
Cones
They are responsible for colour vision and work well in high levels of light.they can detect fine details in an image (Visual acuity). And responsible in well-lit conditions.There are 6.4 million cones per eye.
Binocular Depth Cues 2
require the use of both eyes working together to provide information to the brain about depth and distance.are especially important in determining the distance between close objects. if for some reason our vision is limited to the use of only one eye, tasks requiring us to focus on detail over short distances can be difficult to accomplish.
Monocular Depth Cues 2
Monocular depth cues require the use of only one eye to provide information to the brain about depth and distance, but they also operate with both eyes. Most depth cues are monocular, so we can still perform many daily activities if we lose vision in one eye
Optic Chasm
This occurs because the transmission of visual information from each retina involves a partial crossover of neural pathways. The point where the axons cross is called the optic chiasm.