Basic Learning and Perception

 

William James: infants perceive the world as a

 

Is this really the case?

 

Learning Capacities/Processes/Mechanisms

 

Learning is a change in behavior as a result of experience.

 

Babies born with innate (built-in) learning capacities.

 

Four mechanisms for learning:

 

Classical Conditioning (CC) – Pavlovian

 

Reflexes make CC possible:

 

•        new stimulus paired with a stimulus that already causes reflex.

 

Helps organize world - recognize events that co-occur.

 

E.g., Sucking and salivation 3-4 hours after feeding.

 

Babies respond only to stimuli pairing with

 

Operant Conditioning (OP) – Skinner

 

Infants operate (act) on environment:

 

Stimuli following behavior affect chance of act occurring again.

 

Operant conditioning limited to sucking and head turning:

 

•        Infants turn head for sugar-water reinforcer.

•        Suck faster to see visual designs or hear music.

•        Kick leg to see mobile move.

 

Novelty preference: Habituation & dishabituation

 

•        Babies born with preference for

 

Habituation:

  1. Repeated presentation of a stimulus leads to decline in interest
  2. A new stimulus is then presented.
  3. Renewed interest is called dishabituation.

 

 

•        Allows infants to learn about new things.

 

•        Type of study? Judging gender, beauty, and categorization.

 

Habituation speed best IQ predictor: Infancy to 11 =

 

Imitation – evidence of recall

 

Neonates imitate facial expressions (Meltzoff & Moore, 1977).

 

Why? Disappears at 3 months. So, it is a reflex?

 

•        But deferred imitation: behavior modeled after adult stops – perhaps voluntary?

 

Helps baby share states: notice similarity of their behavior to others.

 

Question: How does baby know its tongue maps onto adult tongue?

 

 

Imitating intentions

 

l      When 18-month-olds see a person apparently try, but fail, to pull the ends off a dumbbell, they imitate pulling the ends off

l      They do not imitate a mechanical device at all

 

 

Perception

 

l      Sensation: Refers to the processing of basic information from the external world by the sensory receptors in the sense organs and brain

l       

l      Perception: The process of organizing and interpreting sensory information about the objects, events, and spatial layout of our surrounding world

 

Touch

 

Fundamental means of interaction:

Important for early physical emotional growth.

 

•         Few days: Mothers recognize infant by stroking cheek.

 

•         Most reflexes are touch related.

 

Infants put new objects to mouth and then look at it:

this exploratory mouthing stops at 6 months.

 

Newborns sensitive to:

 

Temperature: 

Pain: Circumcision = ­ heart rate, blood pressure.

 

Taste

 

Infants suck sweet liquid longer than water.

 

•        Newborns relax face with sweet things:

•        purse lips with sour things:

•        arch mouth with bitter things.

 

Smell

 

Neonates smile with banana, frown with rotten eggs.

 

They locate smells and turn away from nasty ones (NH3)

 

•        Breast fed newborns (only) recognize mother by smell.

•        Bottle fed babies prefer lactating to non-lactating women.

 

Why?

 

Hearing

 

Newborns hear many sounds – but more responsive to some.

 

•        Prefer complex sounds (voices, noises) to pure tones.

•        By 3 days: differ between 2 and 3 syllable utterances.

•        4-6 months: prefer Mozart minuets with natural pauses to minuets with awkward breaks.

 

Very sensitive to human voice: By 3 months, infants:

 

  1.  Differ between ba, ga, ma, na.
  2.  Screen out sounds (speech and others) in other languages.

 

We make it easy– Motherese.

 

Helps with emotions:

 

 

Vision

 

•        Vision is the most important – but least mature sense.

 

Neonates’ lens muscles, retina, and optic nerve underdeveloped.

 

Born with poor visual acuity:

 

But, infants actively scan visual field: e.g., to track a moving object.

 

•         By 3 months, they focus like adults

•         By 6 months, visual acuity is 20/100.

•         By 2 years, near adult level.

 

Color:

 

•         Newborns see color: prefer color to gray.

•         By 2 months, discriminate hues across color spectrum.

•         By 3-4 months, group colors as adults (reds, greens).

 

Why does this develop so early?

 

Depth Perception (DP)

 

Need DP to interact/explore environment (grasp, crawl, walk)

 

•         World is 3D, but retinal image is 2D

 

Do young infants perceive depth?

 

l      This 7-month-old infant is using the monocular depth cue of relative size

l      Wearing an eye patch to take away binocular depth information, he is reaching to the longer side of a trapezoidal window

l      This behavior indicates that the baby sees it as the nearer, and hence more readily reachable, side of a regular window

 

The Visual Cliff

 

l      Gibson & Walk (1960) - Visual Cliff

l      Found that the young locomote to shallow side and avoid the deep side, even if moms call the infant from deep side

l      Suggestion that age of crawling onset determined avoidance of deep side

 

l      Richards & Rader (1981)

l      Found that infants with an early onset of crawling still crossed to deep side

l      Indicates that the depth perception needs to develop before infants can use it in their locomotion and not the other way around

 

Pattern perception

l      Two-month-old infants can analyze and integrate separate elements of a visual display into a coherent pattern

 

l      Seven-month-olds also see the overall pattern here and detect the illusory square

l      Infants are also able to perceive coherence among moving elements

 

 

Pattern Perception

 

Do infants prefer some patterns?

 



 

 

3 weeks: large squared checkerboard.

8 weeks: small squared checkerboard.

 

Contrast sensitivity

 

Why do babies prefer some patterns?

 

Resolve more easily details of large contrast than small contrast.

 

If infants cannot resolve small details they see a blob.

 

Combining pattern elements

 

•        Neonates attend to high contrast areas – e.g., hairline of a face.

•        2 months: inspect internal features of shape (e.g. face).

•        2-3 months: combine pattern elements.

•        3 months: differ between human point-light display and disorganized version of same movement.

 

Perception of human face

 

l      From birth, infants are drawn to faces because of a general bias toward configurations with more elements in the upper half than in the lower half

l      From paying attention to real faces, the infant comes to recognize and prefer his or her own mother’s face after about only 12 cumulative hours of exposure

 

Do babies have innate attention mechanism for faces?

 

Neonates track a face-like pattern longer than others.

 

But: can’t discriminate static face from equally complex pattern.

 

By 2-3 months:           prefer facial pattern to others, recognize mother

                                    differentiate photos of 2 strangers,.

 

By 7 months:  treat happy faces differently from sad faces.

 

Remember: this evidence comes from studies with pictures.

 

Object Perception – 3D

 

Size and Shape Constancy

 

Do infants develop a single representation of an object even though it changes shape and size?

 

YES!

 

•        Newborns know objects’ real size: Study with 2 cubes.

 

•        Similar findings with shape constancy.

 

Perception of Objects as Distinct, Bounded Wholes

 

Piaget: infants don’t use same cues as adult to perceive objects – they do not separate connecting objects.

 

Liz Spelke:  3- to 5-month-olds in the moving rod study.

 

Intermodal Perception

 

We often combine modalities – sense systems: Intermodal perception.

 

Develops early: Infants turn head based on sound to look at an object.

 

•                    1 month: infants know shape of something in mouth  - pacifier (Meltzoff)

 

•                    4 months: infants connect what they hear to what they see:

 

                                    e.g., watch the “right” movie (blocks) for the sound (clacks).

 

Probably just correlation but:

 

1.

 

2.