week 5: perceptual development visit website! midterm in two weeks!
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Week 5: Perceptual developmentWeek 5: Perceptual development
Visit website!Midterm in two weeks!
Perceptual DevelopmentPerceptual Development
3 Methods of determining infant perception Visual Preference
– Developed by Fantz– Infant in chamber with peephole, what do they look at
most?
Perceptual DevelopmentPerceptual Development
4 Methods of determining infant perception
Visual Preference Evoked potentials
Perceptual DevelopmentPerceptual Development
4 Methods of determining infant perception
Visual Preference Evoked potentials High Amplitude sucking Habituation/dishabituation
Senses of the NewbornSenses of the Newborn
Sense Newborn Capabilities
Vision Least developed sense; accommodation and visual acuity limited; sensitive to brightness; discriminates some colours; tracks moving targets
Hearing Turns to a sound; can differentiate loudness, direction, frequency; very responsive to speech; recognize mother’s voice
Taste Prefers sweet; discriminates between sour, salty, bitter, sweet
Smell Detects odours; turns away from unpleasant ones; Breast-fed babies can tell own mother’s breast and underarm odor
Touch Responsive to touch, temperature change and pain
Senses continuedSenses continued
Infants legally blind at birth– 20/600 at birth, by 12 months, down to 20/100
Auditory perception good– Esp speech perception
Have likes and dislikes re. Food– Have sweet tooth like many of us
Show aversion to unpleasant smells– Wrinkle their noses at bad smells
Babies like to be touched– Massaged preemies grow faster
Pattern Perception (0-2 months)Pattern Perception (0-2 months)
Prefer moderately complex stimuli over highly complex stimuli
Like a lot of contrast, like black on white
Examples: Which will babies prefer?Examples: Which will babies prefer?
Examples: Which will babies prefer?Examples: Which will babies prefer?
This one, due to high contrast!
Pattern Perception (0-2 months)Pattern Perception (0-2 months)
Prefer moderately complex stimuli over highly complex stimuli
Like a lot of contrast, like black on white Show externality effect
Externality EffectExternality Effect
Seen at 1 month!
Externality Effect now Obsolete!Externality Effect now Obsolete!
Gone at 2 months
Pattern Perception (0-2 months)Pattern Perception (0-2 months)
Prefer moderately complex stimuli over highly complex stimuli
Like a lot of contrast, like black on white Show externality effect Like curvy things, contours
Which will babies prefer?Which will babies prefer?
Which will babies prefer?Which will babies prefer?
This one!! It’s curvilinear
Pattern Perception (0-2 months)Pattern Perception (0-2 months)
Prefer moderately complex stimuli over highly complex stimuli
Like a lot of contrast, like black on white Show externality effect Like curvy things, contours Vertical symmetry
Which will babies prefer?Which will babies prefer?
Which will babies prefer?Which will babies prefer?
This one! It’s symmetrical!
Later Form Perception: 2 – 4 Later Form Perception: 2 – 4 monthsmonths
Are scanning whole objects Start to show a preference for the human face
Face perceptionFace perception
Babies seem to like to look at faces – Why?– Contrast– Curvy– Symmetrical
Take all features into Take all features into account…account…
Face perceptionFace perception
Babies seem to like to look at faces – Why?– Contrast– Curvy– Symmetrical
Will track a face-like picture over something else
Guess which baby prefers?Guess which baby prefers?
Guess which baby prefers?Guess which baby prefers?
Face perceptionFace perception
Early on, spend more time looking at edges and contours than at middle of face
By 3 months clearly prefer normal faces, and that of own mother, and that of “attractive” people
By 7 months, can categorize and remember faces
By 8-10 months, can interpret emotion in faces
Meaning of face preferenceMeaning of face preference
Could be simply a result of stimulus preferences
Could be social– Dannemiller & Stevens, 1988– Data from eye gaze studies…
We as adults have a “face processing area”
Intermodal PerceptionIntermodal Perception
Enrichment vs differentiation theory– Senses separate; must integrate vs. senses
integrated; must differentiate
Former is probably correct– Bahrick’s research
Integrating modalitiesIntegrating modalities
Babies need to achieve three tasks:– Attending
At 5-7 months, sight and sound well integrated
– Identifying Can integrate two sense to identify source or objects
– Locating They can integrate visual and grabbing information
to time a grasp properly
Infants’ spatial abilitiesInfants’ spatial abilities
Chapter 8
Babies’ 3D visionBabies’ 3D vision
Have binocular vision, or stereopsis, by 3 months
Can only use 2D pictorial cues at 7 monthsShow evidence of perceiving depth by 1
month, but do not interpret it until they are actively crawling
Visual CliffVisual Cliff
Gibson and Walk’s animal studyCrawling infants won’t cross to mom!If placed on visual cliff at 2 months, heart
rate DEceleration, i.e. interestRichards & Rader (1981)
InteractionInteraction
Babies who move understand principles of movement better
Will search for objects that have changed location whether due to object’s movement, or to own movement
Bai & Bertenthal (1992)
Other spatial/ pictorial cuesOther spatial/ pictorial cues
Have depth perception Show size constancy to some extent, esp with
motion between 1 and 3 months, but not fully until 6 months
Can’t use linear perspective until 7 months See subjective contours at 3 months
Subjective ContoursSubjective Contours
Other spatial/ pictorial cuesOther spatial/ pictorial cues
Have depth perception Show size constancy to some extent, esp with
motion between 1 and 3 months, but not fully until 6 months
See subjective contours at 3 months Appear to have mature understanding of objects
Spelke’s Rod and Frame testSpelke’s Rod and Frame test
Spelke’s Rod and Frame Test, cond’Spelke’s Rod and Frame Test, cond’
Babies know that it is not 2 separate rods, but rather one whole!
Children’s Knowledge of ObjectsChildren’s Knowledge of Objects
Baillargeon’s work: Babies seem to have knowledge about objects at a very young age
Uses “Violation-of-Expectation” paradigm to infer 4 month old infants’ knowledge about occluders
Violation of Expectation: Habituation Violation of Expectation: Habituation EventEvent
Screen moves through 180 degree plane until baby gets bored
Violation of Expectation: Test Event Violation of Expectation: Test Event #1: Possible Event#1: Possible Event
Screen moves through 112 degree plane and stops at occluder
Violation of Expectation: Test Event # Violation of Expectation: Test Event # 2: Impossible event2: Impossible event
Screen moves through 180 degree plane despite occluder
Violation of Expection: ResultsViolation of Expection: Results
Babies “are surprised” by the impossible event Find the same thing with other object properties
like containment and support Spelke’s research with the moving rod is the same
idea
What does it mean?What does it mean?
Babies may be born with principles of cohesion, continuity and contact
Maybe not innate knowledge about objects per se, but innate constraints
Possess tools to build cognition from birth: object concept present early on!
Later Form Perception: 6 months to 1 Later Form Perception: 6 months to 1 yearyear
By 7 months get linear perspective By 9 months can extract whole from a random dot
pattern By 12 months, they watch a single point of light
trace an object, then act like they’ve seen the whole object
SummarySummary
Infants are born with fairly strong capabilities Infant perception develops rapidly over the first
year of life By 12 months, they can see well and are moving,
and are largely able understand their environment!
How old is this woman?How old is this woman?
What do you see here?What do you see here?
Ambiguous FiguresAmbiguous Figures
Physiological perception is done early; cognitive perception develops later
They can’t shift back and forth between pictures until they are 10-11 years old!
Later Perceptual development, Later Perceptual development, con’dcon’d
Children also have trouble telling some letters apart:
M W
b d h
Spatial orientationSpatial orientation
Children before 3 have a hard time keeping track of their environment
Tend to view things in a straight linePoor cognitive mapping
Spatial CognitionSpatial Cognition
Herman, Shiraki, & Miller, 1985:– Examined 12 younger (3 – 4) and 12 older (4.5 – 5.5)
nursery school children who had been at the same school for the same amount of time
– Brought them to 3 locations and asked them to point out 5 landmarks
– Older a bit better than younger, but still not great– Very young children have difficulty inferring spatial
relationships, even in familiar environments
More Spatial ProblemsMore Spatial Problems
Field Dependence / Independence– Have trouble with this until they are 10– Embedded Figures Task
Embedded Figure #1Embedded Figure #1
Embedded Figure #2Embedded Figure #2
More Spatial ProblemsMore Spatial Problems
Field Dependence / Independence– Have trouble with this until they are 10– Embedded Figures Task– Role of Inhibition and Cognitive Flexibility,
hard to separate figure and ground
Summary of Perception and Spatial Summary of Perception and Spatial CognitionCognition
In infancy, focus is on what infants can or cannot see, i.e. colours, patterns, depth, etc…
How much is present at birth? How much develops?
Once they see, they improve in how flexibly they see items
They also improve in how they mentally represent the space around them