Chapter 13 Flashcards
What is sensation?
- neural activity triggered by a stimulus activating a sensory receptor
- results in sensory nerve impulses travelling down sensory nerve pathways to the brain
- involves sensing the existence of a stimulus
What is perception?
- multistage process in the central nervous system
- included selection, processing, organization and integration of information received from the senses
- identical sensations can yield different perceptions
- determination of what a stimulus is
What kind of constraints are the sensory systems functions ?
Individual structural constraints
What are the 2 sections of visual development?
1) Visual sensation
2) visual perception
What is visual acuity?
Sharpness of sight
What vision do infants have?
Functionally useful but unrefined vision (20/400)
How far can infants see?
Can see faces from around 0.5m away, but beyond that, can’t see clearly
By 6 months, what does an infants vision look like?
Vision is adequate for locomotion through he environment
What does an infants vision look like at age 5?
20/30
What does an infants vision look like at age 10?
20/20
But there are cases that they don’t have 20/20 vision at the age of 10
What is presbyopia?
A refractive error that makes it hard for middle-ages and older adults to see things up close
What do older adults need more of in reference to vision?
They need more light in dim environments
What are cataracts?
Cloudy area in the lens of the eye, difficult for the right amount of light to get through
What is glaucoma?
Eye disease, cause vision loss, related to optic nerve damage, slow and progressive
What is age-related maculopathy?
Disease that affects area of the retina that effects the details that people will see
What are some symptoms of visual problems?
- lack of hand-eye coordination
- Squinting
- under or overreaching for objects
- unusual head movements
Explain retinal disparity
Difference in images received by the 2 eyes as a result of their different location
The fact that the left and right fields of vision provide slightly different visual images when focusing on a single object
Explain motion parallax
Change in optical location for objects in motion at different distances
a type of depth perception cue in which objects that are closer appear to move faster than objects that are further
Explain optic flow
Change in the pattern of optical texture as we move forward or backward
a form of visual streaming which occurs as we are moving continuously in one direction. It occurs because the image of the same object are constantly changing with regards to which area of the retina they stimulate. E.g. pilot landing a plane
What is perception based on?
On information about edges
- edges are classified as either boundaries or not boundaries
What is figure and ground perception?
- the ability to see objects of interest seen as distinct from background
- people instinctively perceive objects as either being in the foreground or in the background
What is whole and part perception?
- parts of a picture or object discriminated from whole, yet can be integrated
- can see a whole picture but can also see different parts
When is figure-and-ground and whole-and-part perception well developed?
Well developed in most children by age 9
What is size constancy and give an example
- allows us to perceive an object as having the same size even when seen at different distances
E.g. when you see a car driving away form you it looks like the car is shrinking even though it stays the same size
