Perceptual Development in Infancy
o
Our knowledge of
the world revolves around the ways we interpret sensory information
n
Much of what we
perceive is processed implicitly without our awareness
o
Yet, is has a
major impact on how we process information and ultimately who we are as humans
n
How do we know
what is music or noise
n
Why do we react
to colors differently
n
What do we find
attractive
Face Perception
n
Who is this?
Picture Perception
o
What is this?
How do you know?
Would an infant know?
People and Objects
o
Who is more
attractive?
o
Or, which is a
better example of a
dog?
o
Would an infant
agree?
An infant’s world
Theoretical Positions
o
Empiricists/Constructivists: All of perception is learned through active
interactions in the world and cultural transmission
o
Nativists: Perceptual
Abilities are all innate
n
James & Elinore
Gibson:
o
Perception is innate, and infants naturally
perceive “affordances” or important environmental information. We have evolved
to do this
Theoretical Positions: What the data will
show
o
Many perceptual
abilities are innate as argued by Gibson
n
This is
especially true with respect to abilities that apply to all member of the
species and is probably related to both genetic canalization and brain growth
o
Other abilities
are learned, but through innate mechanisms (e.g., language, face perception)
n
These are
probably universal for the specie, yet have cultural influences
o
Finally, other
abilities are probably completely learned and culturally dependent
Depth Perception
o
Consider the simple ability to perceive depth
The Visual Cliff
Convergence
o
Begins at
approximately two months of age and provide infants with depth
information
Binocular Disparity
Research of Richard Aslin
with infants
Random Dot Stereograms
Binocular: Retinal Disparity
o
Richard Aslin:
Research showing infants 3-D and non 3-D pictures while wearing glasses
o
Infants by 4 to 6 months perceive and use retinal
disparity
o
Probably an innate skill that develops when the
visual system is mature enough
How do you perceive depth
Texture Gradient
o
Texture decreases
with distance
Relative Size
o
Size decreases
with distance and can be compared with known objects
Interposition
o
Contours or one
object partially block another
Shading
o
Farther away
objects appear darker
Pictorial Depth Cues in Infants (Yonas)
Pictorial or Monocular Cues
o
Yonas & Granrud: Studies
using infants reaching when objects appear at different distances because of
pictorial cues
o
Sensitivity to
these cues emerge around 7 months of age
o
Are they learned
or innate?
n
While they don’t
emerge until 7 months, they seem to be innate
o
Age of onset
doesn’t vary much indicating minimal impact of experience
Perception of Pattern or Figures
o
How do we perceive figure vs
background?
What do you perceive?
How do you know what is figure or ground?
Habituation Procedure
A
A
A
A
A
B
A
B
A
Habituation Data
Subjective Contours Illusion: Infants
perceive by 3 to 4 months (B. Bertanthal)
Motion as an organizer of perception:
Infants perceive by 3 to 4 month (Bertenthal)
Conclusion
o
Gibson appears correct in stating that the
ability to perceive forms in innate. We
have evolved to “pick-up” structure