Perceptual and Motor Development Flashcards
1
Q
sensation vs. perception
A
- Sensation: sensory organs’ detection of physical signals in the environment
- Perception: organization and perception of sensory information into coherent understanding of objects, individuals, and events
2
Q
vision
A
- Vision is humans’ most dominant sense (in most situations) -> Exceptions: language, eating, etc.
- Infants’ visual acuity is low for the first few months of life
- There are subtle differences in infants’ colour perception from adults’ colour perception (can only distinguish shades of white until 2-3 months of age)
3
Q
preferential looking techniques
A
- Can’t use typical adult vision testing techniques on infants -> we can use preferential looking techniques instead
- One of the most powerful methods
- Infants, like adults, choose to spend more of their time looking at objects or events that are interesting, stimulating, or familiar
4
Q
novelty vs. familiarity preference
A
during preferential looking, Infants display both novelty preference (when things are interesting and stimulating) or familiarity preference (when things are familiar) in different contexts (ie. In social contexts – novelty; in abstract contexts – familiarity)
5
Q
using preferential looking to determine infants’ visual acuity
A
- 1 month-olds prefer to look at patterned images over grey images
- However, when the lines in the pattern are close together, young infants can’t discriminate -> their low visual acuity makes it look like those images are solid colours
6
Q
infants’ low visual acuity
A
- In first month of life, infants’ visual acuity is approximately equal to 20/120 (6x worse than perfect human vision)
- This acuity is equivalent to being able to decipher only the top line of a visual acuity test plate
- What causes this low visual acuity?
- Less visual stimulation in utero -> no experience with exogenous light signals until they’re born, resulting in less developed physiology
7
Q
2 types of photoreceptor cells
A
- Rods – activated in low light
- Cones – activated by wavelengths of different colours
- Infants’ cones are less dense and smaller -> less light is processed by infant eyes (only about 2% in infants, vs. The 65% in adults)
- Colours are more poorly differentiated
8
Q
2 other ways infant vision differs from adults’
A
1) Visual scanning: Infants have irregular saccades -> eyes track objects in a more jerky way, unlike adults, who can track objects fluidly
Internal detail
2) 1-month-olds typically scan the perimeter of shapes; 2-month-olds have begun to examine internal details of shapes
9
Q
face preferences
A
- Infants are more attracted to faces than to non-face objects, such as bullseyes
- Their preference appears to extend from their preference for objects with more information on top than on the bottom (they like more detailed things)
- Infants’ face preferences quickly develop, and infants’ prefer looking at their own mothers’ faces over unfamiliar female faces within days of birth
- Infants also prefer looking at faces when adults have rated those faces as more attractive
10
Q
how do infants determine facial attractiveness?
A
- Symmetry
- Averageness (attractiveness is based on average of all faces you’ve seen during your life)
11
Q
face discrimination
A
- Once their visual systems have more fully developed, infants in some ways have better visual discrimination than adults do
- This is particularly true for faces (ex. Human faces vs. Monkey faces)
- Infants can easily differentiate between individual human faces and monkey faces (unlike adults), and can tell apart faces from different ethnicities as effectively as faces from other races (don’t display “other race effect” like adults do)
12
Q
perceptual attunement
A
- At birth, infants have broad perceptual abilities:
- Differentiation between individual faces of their own and different ethnicities (and between individual faces of other species)
- Differentiation between sounds in their own and other language
- Differentiation between musical rhythms from their own and other cultures
- These differentiation abilities decline in the first year of life, as infants begin only to pay attention to the differences in stimuli that are relevant for them (synaptic pruning gets rid of the other synapses)
- While non-native differentiation declines, native differentiation improves
13
Q
auditory perception
A
- Auditory acuity after birth is just as good as adults’
- Newborn infants turn their heads toward the direction of a sound
- Infants’ auditory localization is not well developed beyond side-to-side discrimination
- Infants aren’t good at the triangulation method of sound localization as adults are, possibly because of small head size or limited experience in sound localization
14
Q
intermodal perception
A
- Infants’ ability to match stimuli from different sensory modalities
- These abilities appear to be present from the earliest ages tested
- Some of the most influential evidence of intermodal matching comes from infants’ abiltieis to match heard and seen speech
- As early as 2 months, infants have been shown to match the sound of what they’re hearing with the appropriate visual display (ex. They hear “ba” or “da” sounds and look longer towards whichever face is saying “ba” or “da”)
15
Q
intermodal perception study
A
- Infants can also detect mismatches between heard and seen speech, even from languages with which they are unfamiliar (ex. Hindi)
- used infant face scanning (eye tracking)
- We know from previous research that infants prefer to look at the eye region of the face (except between 8-12 months)
- But when the speech is mismatched, infants prefer to look at the mouth
- Audition and vision may be innately linked, which makes it easy for babies to pick up on this mismatch
- This ability to differentiate is gone by 11 months
