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
What is shape constancy
- ability to perceive that a shape remains the same in different orientations
When do children differentiate directional extremes such as high/low, over/under, front/back?
By 3-4 years
When do children differentiate angles and diagonals, but may still confuse right and left
By 8 years of age
What is preferential looking?
- infants fixate on new objects for a longer period of time
- attention wanders from objects to which the infant is habituated
What are the 2 types of kinaesthetic development?
1) Kinesthetic sensation
2) Kinesthetic perception
Where does Kinesthetic arise from?
Proprioceptors
What are the 2 types of proprioceptors?
Somatosensors
Vestibular apparatus
Where are somatosensors located?
- under the skin, in the muscles, at muscle-tendon junctions, an in joint capsules and ligaments
Where is the vestibular apparatus found?
Located in the inner ear
What does the vestibular apparatus do?
Functions to detect the position and movement of our head in spacer
When does the vestibular apparatus start to function?
Age 2 months
What elements are involved in perception?
Tactile localization, manipulation, and movement
Body awareness
- awareness of self and identification of body parts
- laterality
- lateral dominance
- side preference
- spatial orientation
- directionality
What is tactile localization?
- the ability to identify, without sight, the exact part of the body that has been touched
What is haptic memory?
Form of sensory memory specific to tactile stimuli
When do children start identifying body parts?
Age 6
Mastered by 9
When do children start knowing the body’s spatial dimensions: up and down, front and back and finally side to side
Up and down, then front and back- age 3
Side to side- age 4
When do children start knowing laterality (knowing side of body are distinct)
By age 4-5
show adult like responses (very accurate left-right discriminations) by age 10 or earlier
What is lateral dominance?
Preferring one eye, ear, or foot over the other; a consistent preference
When is handedness established?
Around 4
What is pure dominance?
The favourite side is the same for the whole body
When does spatial orientation improve?
Between 6-8 years
What is directionality?
Ability to project body into space and to grasp spatial concepts about movements or locations of objects in the environment
- linked to laterality
What are the 3 structures involved in hearing?
- external ear
- middle ear
- cochlea of the inner ear
Explain infants’ threshold for sound?
Infants’ threshold for sound is higher than adults’ but allows detection of normal speaking voice
When do infants hear low-frequency sounds well?
At 3 months
What is absolute threshold? (Auditory)
Minimal detectable sound
- smaller level of tone that can be detected by normal heaving when there are not other sounds
What is differential threshold?
Distinguishing between (similar) sounds
Has to do with intensity
What are some auditory changes with aging?
- hearing loss is more frequent
- some loss might have a physiological source
- some less might result from lifelong exposure to environmental noise
- absolute and differential thresholds generally increase
- hearing amid a noisy background is more difficult
What is another word for hearing loss?
Presbycusis
Auditory perception involves the perception of the following:
- Location
- Differences in similar sounds
- Patterns
- Auditory figure and ground
When do children locate distant sounds?
Age 3
When can infants discriminate basic speech sounds
1-4 months of age
What are the 3 properties that give rise to patterns?
- time
- intensity
- frequency
When are temporal patterns perceived?
By 1 year
When are intensity changes detected
Between 5-11 months
What is intermodal perception?
Perception of unitary objects or events that make information simultaneously available to more than one sense
What are amodal invariants?
Patterns in space or time that do not differ across modalities
