1. PSYC 206: Life-Span Development Lecture 5 Aylin Küntay
How different theories explain changes in early infancy Biological Changes
PSYC 206: Life-Span Development
Lecture 5
Aylin Küntay

2. SHOW and TELL: Social smile and laughter

3. Mechanisms of Developmental Change
Environmental-Learning Perspective

4. Classical Conditioning
Sight of a light (CS) elicits no particular response
Loud sound of gong (UCS) causes baby to blink (UCR)
Sight of light (CS) is paired with sound of gong (UCS), which evokes an eyeblink (UCR)
Sight of light (CD) is sufficient to cause the baby to blink (CR), evidence that learning has occurred

5. Operant Conditioning
An organism will tend to repeat behaviors that lead to rewards and will tend to give up behaviors that fail to produce rewards or lead to punishment
Requirement: Behavior must occur before it can be reinforced

6. Operant Conditioning
After only 25 occasions on which the head turning was reinforced with the pacifier, most of the babies had tripled the rate at which they turned their heads.
Conversely, those infants who were rewarded with a pacifier for holding their heads still, learned to move their heads less during the course of the experiment.

7. Mechanisms of Developmental Change
Constructivist Perspective (Piaget)

8. Piaget’s Theory of Developmental Change via Schemas
Assimilation (Incorporated into an existing schema)
Accommodation (Modification of a prior schema)
Equilibration
Leads to developmental stages…

9. Sensorimotor Substages
Age (M)
Description 1
0 – 1 ½
Reflex schemas exercised: Involuntary rooting, sucking, grasping, looking 2
1 ½ – 4
Primary circular reactions: Repetition of actions that are pleasurable in themselves 3
4 – 8
Secondary circular reactions: Dawning awareness of the effects of one’s own actions on the environment, and that extended actions can produce interesting change in the environment 4
8 – 12
Coordination of secondary circular reactions: Combining schemas to achieve a desired effect (earliest form of problem solving) 5
12 – 18
Tertiary circular reactions: Deliberate variation of problem-solving means, with experimentation to see what the consequences will be 6
18 – 24
Beginning of symbolic representation: Images and words come to stand for familiar objects, accompanied by the invention of new means of problem solving through symbolic combinations

10. Mechanisms of Developmental Change
Cultural-Context Perspective

11. Reciprocal Relationships
Presence of milk stimulates infant sucking, which in turn triggers the release of hormones that increase milk production and release

12. Developmental Change Incorporates Cultural Variations
Additional sources of developmental change
Active contribution of other people in the child’s community
Cultural “designs for living” accumulated over the history of the larger social group
Case in Point Bottle-feeding vs. Breast-feeding

13. First Postnatal Bio-Social-Behavioral Shift
Occurs at 2½ Months Social Smiling!

14. BSB Shifts & Subsequent Periods
Shift Point
Developmental Period
Conception
Prenatal period
Birth
Early infancy
2 ½ months
Middle infancy
7-9 months
Late infancy
24-30 months
Early childhood
5-7 years
Middle childhood
11-12 years
Adolescence
19-21 years
Adulthood

15. Characteristics of the Shift
Biological
Myelination of cortical and subcortical neural pathways
Increased cortical control of subcortical activity
Increased diversity of brain cells
Increase in amount of wakefulness
Decrease in proportion of active (REM) sleep
Quiet (NREM) sleep begins to come first
Social
New quality of coordination and emotional contact between infants and caretakers
Beginning of “crying on purpose”
Behavioral
Better retention of learning
Increased visual acuity and better visual scanning
Decreased fussiness and crying
Visually initiated reaching  visually guided reaching

16. Biological changes in infancy

17. Size and Shape Triple in weight… (3.2 kg  10 kg.)
Add 10 inches height… (50  75 cm)
Change in body proportions…
At birth, head is 70% of adult size and accounts for 25% total body length
Legs at birth are not much longer than their heads; by adulthood, legs account for about half of total height
Result in lowering the center of gravity (balance, walking)

18. Environmental Conditions Influence Growth Rate
Babies born in Malawi face conditions such as widespread mal-nutrition, chronic poverty, disease, and a rising HIV/AIDS infection rate. As a result of this complicated array of factors, Malawian infants grow at a slower rate than their American counterparts.

19. Bone, Muscle, & Gender Bone ossification Increases in muscle mass
First in hand and wrist (pick up)
Increases in muscle mass
Associated with ability to stand alone and walk
Sex differences
Females are ahead 3 weeks prenatal, 6 weeks at birth, 2 years at puberty
Girls get their permanent teeth, start puberty, and reach full size earlier than boys

20. Brain Development Exuberant synaptogenesis (3-12 months)
Density of synapses is double what it will be in early adolescence
As a result of this overproduction of synapses, infants are prepared to establish neural connections for virtually any kind of experience
“Synapses that are regularly used flourish and are strengthened, while those that go unused are gradually ‘pruned away’—that is, they atrophy and die off.” (p. 183)
What might be some educational implications?

21. Brain Development 2½ - 4 months: Surge in visual cortex
6 months: Spurt in motor cortex
7 - 9 months: Rapid growth of frontal cortex (used in integrating information)
Prefrontal area plays a particularly important role in the development of voluntary behavior (e.g., impulse inhibition)