5 - Perceptual development Flashcards
What is the main feature for young infants when figuring out if an object is one or to separate objects?
common movement -0- if the line behind the 0 was moving same pace and direction on both sides infants would perceive it as one object/line. if no movement occurs they are less sure if it is two lines or one passing behind the 0 movement = habituation to --- not - - no movement = habituation to neither
common movement is more important than colour or texture differences
In the -0- experiment what do babies habituate to in each level?
movement = habituation to — not - -
no movement = habituation to neither
Kellman and Spelke 1983
-0- object segregation and movement experiment. who? when?
What other feature of objects do older infants use when determining object segregation?
Gravity.
a) |– b) |_
a has to be one object because that line can’t float by itself
b could be on or two
again gravity is more important than colour/texture differences
what is the first visual cue that develops for us to perceive depth?
Optical expansion:
-as an object comes closer it expands and occludes more and more of the background.
if it expands symmetrically we know it is headed straight for us
How old are infants that show responses to objects ‘heading straight for them?’ What are they using to perceive depth?
- 1 month
- Optical expansion
What are all the things we use to perceive depth in order?
- optical expansion
- stereopsis/binocular disparity
- monocular cues
- lines converging in the distance
- relative size
- object occlusion
What is the second thing that develops to allow infants to perceive depth? At what age?
- Stereopsis due to binocular disparity
- develops suddenly within a few weeks at around 4 months
- the fact that our eyes produce slightly different neural images and the closer an object is, the more different the images will be. our brain calculates the disparity between these images.
What is stereopsis
The process by which the visual cortex compares the disparity between neural images in order to provide depth perception
When does stereopsis develop and why?
- suddenly at 4 months within a few weeks
- development of the visual cortex
What are the monocular depth cues?
- depth cues that can still be used with only one eye working
- relative size
- objects in the foreground occlude objects behind them/ in the background
- lines converging in the distance
When do monocular depth cues develop?
6/7 months of age
What is the last depth cue to develop in infants?
monocular depth cues
How were monocular depth cues tested?
By putting an eye patch on babies and presenting them with that slanty window thingy. (one side is taller than the other so that side seems closer). babies reach for objects closest to them and after 7 months they reach for the tall side
What are monocular cues otherwise known as?
Pictoral cues
Pictoral cues
Monocular cues
What is the slanty window thingy called?
Ames window
For how long do infants continue treating pictures as if they are objects?
19 months - unit they have sufficient experience with them
What is auditory localisation?
When infants turn their head towards a sound source.
What age do infants show auditory localization?
Do this from the moment they’re born
-sound needs to continue for several seconds because they turn they’re heads very slowly
How good is infants hearing?
Born with relatively good auditory development.
the quietest sound an adult can hear is 4 time quieter than the first sound a baby can hear.
When does infants hearing match adults
Not until 6 or 5 years
What can infants respond to in music?
- rhythm
- melody
- temporal organisation
- prefer music with pauses between phrases rather than in the middle
- consonance and dissonance (babies prefer consonance)
Dissonance
Jarring horrible sounding chord
often minor sounds
consonance
nice chord that goes well. A major
Is music perception thought to be innate or learnt
innate. we have a biological foundation for music perception
What is the evidence we have a biological foundation for music perception?
Heel lance procedure performed on premature infants to monitor heart rate
Infants less than 31 weeks GA didn’t habituate as quickly when played the same melody with different instruments
Who performed the heel lance procedure to test premature infant habituation to the same melody in different instruments
Butt and Kisilevsky 2000
Butt and Kisilevsky 2000
performed the heel lance procedure to test premature infant habituation to the same melody in different instruments
What is the heel lance procedure?
Non invasive way to measure heart rate and blood stuff in newborns
What was found with regard to infants and melody?
Habituated faster if they heard the same melody played with a different instrument so they can pick out the melody.
If the same notes are re-organized (melody changed) they dishabituate
Infants taste and smell
- show a preference for sweet flavours
- prefer the smell of breast milk (their natural food source) even if they have been bottle fed
How was infants preference for their mother smell shown?
- mothers pad worn next to breast placed on one side
- strangers pad placed on other
- turned more often and spent more time orientated towards mummys breast pad
When does infants smell and taste develop?
before birth
What was the result of the experiment where they injected dye into amniotic fluid vs. dye and sweetener?
more dye present in sweetened mothers urine
Marlier et al. 1998
Babys prefer the smell of their own amniotic fluid to another
Babys prefer the smell of their own amniotic fluid to another
Marlier et al. 1998
Teicher and blass 1997
- amniotic fluid promotes post birth feeding in rats
- rats find their way to mum for food source
- if she was washed straight away they don’t find the food source
Is taste innate?
We think so. Newborns facial expressions match adults when experiencing the following flavours
a) neutral (water)
b) sweet
c) bitter
d) sour - most pronounced
Touch perception. walk me through it.
- starts with oral exploration - babies put everything in their mouths to learn about
- their own bodies
- taste
- texture and other properties
- around 4 months manual gradually takes over exploration as manual dexterity increases
- bang rigid objects, stroke textured ones
- rotate them and move from hand to hand to facilitate visual perception
what is intermodal perception?
combination of information form two or more senses e.g visual and oral experience, visual and sound experience
How old where babies that showed preference for the video clip that linked with the sound they were hearing?
-4 months
How old are infants that associate facial expressions with emotion in voices?
5 MONTHS
Intermodal experiment - rings
- infants held rings under a cloth that prevented them seeing rings or own bodies
- some rings connected by rigid bar, some by flexy chord
- infants look longer at the rings they haven’t played after the experiment
Define sensation
sensation is the processing of information from the external world using the sense organs and the brain
define perception
Perception is the organisation of sensory information about events, spatial layout and objects
How do we test sensation?
- habituation
- operant conditioning (sucking rate)
- preferential looking
What is visual acuity?
The sharpness and clarity of visual discrimination
How old do infants get adult like visual acuity?
pretty much there at 8 months
actually 6 years
How do we test visual acuity?
Preferential looking at patterns (stripes or checkerboards. thinner stripes/squares can cause it to appear like one grey mass for infants)
What vision do newborns have?
20/120
Why do infants prefer looking at patterns with high contrast?
Because they have difficulty distinguishing between areas of light and dark
Why do infants have different vision to adults?
The have different size, shape and spacing of cones in the fovea (central area of retina)
What age do infants stop having limited colour vision?
2-3 months
What type of displays do infants show preference for?
Top heavy displays, ones with more features in the top than the bottom
How many hours before newborns show preference for mothers face?
12 cumulative hours
How old are infants when they stop being able to distinguish monkey faces so well?
9 months, can do it at 6
How old are infants when they start showing preference for primary caregivers gender faces?
3 months
What happens with regard to faces with experience of the infant?
come to be able to distinguish facial expressions and the better distinguish types of faces they are familiar with
How old are infants that show preference for attractive faces?
from birth
How did they test the attractive face preference thingy?
Did the makeup of a woman ugly vs pretty. she din’t know what she looked like. The infants interacted more with her when she was perty
What are the two things we need for visual processing?
visual acuity
pattern perception
Talk about scanning and tracking.
- infants less than 2-3 months tend to scan the perimeter of objects only (because these are areas of highest contrast)
- infants above this age look at internal features too
- infants can’t track moving objects until 2 months and even then the objects have to be very slow moving.
What is perceptual constancy?
perceiving and knowing that an object is still the same size, shape, colour even as it moves further away/closer and gives a different retinal image
How did they test perceptual constancy??
habituated infants to one cube
placed another cube x2 bigger but x2 further away so it produced the same retinal image
infants looked longer at bigger cube showing they knew it was bigger
Which view (nativist or empiricist) do we take for perceptual constancy?
nativist
what don’t you need for perceptual constancy?
experience
