Perceptual Development Flashcards
Sensation
The processing of the external world through receptors in the sense organs
Pattern of light hitting the retina
Perception
Organizing and interpreting the sensory information
The experience of seeing
Empiricist
Infants perceive very poorly; experience vital for sense development
Nativists
Perceptual development progresses through maturation, not experience
Vision
- The least developed sense at birth
It’s ridiculously hard - “instinct blindness”
- Segmenting objects
- Perceiving depths
- Not running into things
- Recognizing people
Acuity Development
- Newborns don’t see well
- Nearly as good as adults’ by 8 months
Vision Development
- Many abilities poor at birth, but near-adult levels by 8 months
- Poor color vision/ contrast sensitivity - improvements rapid, mostly due to rapid maturity of foveal cones
Control of eye movements
- Can’t do “smooth pursuit” until 4 months
- Improvements due to maturation, not experience
- Scanning abilities limited
Colour Vision
- Not present at birth, discrimination seems adult-like by 2 months
- Cone development
- Categorical perception: perceiving clusters of likeness that do not necessarily transfer to physical likeness
- Adults perceive color categorically, not by absolute wavelength changes
Face Perception
Newborns prefer faces
Due to faces’ characteristics
- Symmetry
- High contrast
- More stuff in top
- They move
Newborn face tracking goes away by 1-2 months, back and improve dramatically by 3-4 months
Two systems view: An initial crude face perception system gets replace by more sophisticated one
Given sufficient experience with an unfamiliar face, will come to recognize it
- Habituation/dishabituation procedures
Perceptual Narrowing
Babies’ face discrimination abilities narrow based on the faces they experience
- Species
Gender:
- If raised primarily by female caregiver, prefer& can better discriminate female faces by 3 months (same for male)
Infants prefer attractive faces
Attractive faces are average faces
- Attractive faces may be easier to process than unattractive ones because they’re similar to the prototype
Size (or perceptual) Constancy
An object is perceived as maintaining its size despite changes in its distance from us (& hence, changes to its retinal image size)
Size Constancy is Innate (Slater et al., 1990)
Object Segregation
The perception of separate objects in the visual array
Motion Cues to Object Segregation
- Common motion = elements that move together (likely) part of same object
Studies claim that motion cues are innate while the books says that its learned
Perceiving Pictures
Newborns can recognize 2-D versions of 3-D objects, but symbolic nature is lost on them… babies try to pick up pictorial object
- Stops by 19 months
Depth Perception
3 types of depth cues
- Binocular cues: involve having two eyes
- Monocular/pictorial cues: exist in 2D pictures
- Dynamic cues: seeing objects moving
Binocular cues
- Binocular disparity: retinal image of each eye slightly different
- Our visual system fuses the two images so we don’t see double
- Using binocular cues to see depth called stereopsis
- Convergence: eye muscles more tense when looking at close objects
Stereopsis
Need 2 eyes to see image
Descartes
- We are endowed with innate computational systems to convert binocular information into depth percept
- Maturation of this system might take some time, but it’s maturation not experience
Berkeley’s theory of the development of depth perception
Babies learn to associate binocular cues with depth by building associations between amount of eye strain and length of reach over time
Stereograms
Artificially generated images that can only be seen when they are fused by the two eyes
Stereopsis permanently impaired if strabismus (two eyes do not line up in same direction) not fixed by age of 3
Pictorial Cues: In 2D images
Interposition: overlapping shapes in front
Convergence in the distance: parallel lines meet at the horizon
Texture gradients: repeating patterns get smaller when farther away
Testing Pictorial Depth: The Ames Window
- 7 months old reach to long but 5 months don’t
- Suggest pictorial cue develops around 6 months
Dynamic Cues: Motion
Motion parallax: Relative movement of near and far objects to the motion of the eye
- When you move your head left, near object move faster/ more right than far objects
Optical expansion: retinal image of objects expand in size as they get nearer to you; the nearer of two objects expands more quickly
Carry non-crawlers across cliff; heart rate changes by 2months; also perceive depth
- Heart rate decreases: interested not scared
- Perceiving depth is innate; fearing it is not
Depth perception development
- Dynamic cues - 1 month
- Binocular cues - 4 months
- Pictorial cues - 6 months
Auditory Perception
At birth newborns:
- Prefer own mom’s voice to other moms’ voices
- Prefer language sounds to non-language sounds
- Prefer own language to a foreign one
Critical Period for Hearing
Cochlear implants - the earlier children are implanted, the better they do (best before 2)
