Developmental Psychology: Challenges and Research

Challenges to Studying Development

• Developmental psychology studies behavioral changes throughout the lifespan from birth to death
• Researching the reasons behind these changes presents several challenges
• A does not cause B by simply preceding it, as illustrated by the post hoc fallacy
• Bi-directional influences affect development; children's development shapes their experiences, and vice versa
• Cultural differences are factors which affect this
• Cohort effects: systematic differences in people from different time periods

Cohort Effects and Research Designs

• Cohort effects are differences that are rooted in the experiences of sets of people who lived during one period
• Two main research approaches are contrasted
• Cross-sectional designs study groups of people of varying ages simultaneously
• Longitudinal designs study the same people over a duration

Influence of Early Experience

• Early exposure to the world has a major impact of development, as does later input
• The myth of infant determinism: the false belief that early experiences dominate or even determine later development
• Myth of parenting determinism: parental intervention decides a child's development
• Myth of childhood fragility: false assumption that children are easily damaged

Nature vs. Nurture

• Both nature and nurture are vital in shaping development
• Gene-environment interaction: genetic impacts on behavior depend on the environment
• Nature via nurture: children with genetic predispositions seek out and create their own environments
• Gene expression: environmental experiences activate or deactivate genes

Physical Development Compared to Other Species

• Humans require a lot of developing after birth physically, cognitively, and socially
• Foals can stand to walk in an hour versus humans in 12 months
• At birth, the human brain is 25% of its adult weight versus a chimpanzee at 60%
• Still, most dramatic changes during conception and prenatal development

Conception and Prenatal Development

• A zygote is formed when a sperm cell fertilizes
• Germinal period: 0-2 weeks, conception to implantation, including the blastocyst
• Embryonic period: 2-8 weeks, the heartbeat begins, body parts appear, sexual differentiation begins, and major organs are established
• Fetal period: 9th week-birth, with the last 3 months seeing rapid growth of the body and brain

Genetic Disruptions and Premature Birth

• Genetic mutations can be caused by disruptions
• Trisomy 21 (Down syndrome)
• Trisomy 18 (Edwards syndrome)
• Trisomy 13 (Patau syndrome)
• The risk of mutations increases with maternal age
• Sex chromosome disorders
• Klinefelter's (XXY)
• Turner's (X) syndromes
• Premature birth is birth before 37 weeks
• Viability is reached at around 24 weeks (39%) or 25 weeks (50%)
• Corticosteroids help lung development, thus preventing respiratory distress syndrome
• Record for premature birth: 21 weeks + 1 day!

Physical Development - Motor Skills

• Prone, lift head at 1 Month
• Chest up, Use arms for support at 2-4 Months
• Roll over at 2-5 Months
• Support some weight with legs: 5-8 Months
• Sit without support at 5-9 Months
• Stand with support at 5-10 Months
• Pull self to stand at 6-11 Months
• Walk using furniture for support at 7-12 Months
• Stand alone easily at 9-14 Months
• Walk alone easily at 10-18 Months

Physical Development - Toddler to Adolescent

• Increases in coordination and processing are seen speed throughout childhood.
• Myelination in the brain also influences physical changes
• Puberty causes Hormonal changes
• Estrogens and androgens influence primary and secondary sex characteristics
• Timing depends on genetics and the environment

Physical Development - Older Adulthood

• Strength, agility, and cognitive processing peaks in early twenties
• Reproductive changes in women
• Menopause occurs at 50 years old
• There is a decline in female hormones with age
• Reproductive changes in men
• Some men lose the ability to father children
• Much of what was thought to be primary aging is actually secondary aging

Studying Infant Cognition

• Techniques used to study infant perception and memory include.
• Preference technique
• Habituation techniques
• Using rewards
• This works because babies prefer certain stimuli, notice new things, and repeat rewarding actions

Piaget's Work: Cognitive Development

• Children think and organize the world differently than adults
• Schema: mental models used to interpret experiences
• Assimilation: fitting experiences into schema
• Accommodation: changing schema to fit new experiences

Piaget's Stages of Cognitive Development

• Sensorimotor stage (birth - 2 years)
• Preoperational stage (2-7 years)
• Concrete operational stage (7-12 years)
• Formal operational stage (12 years onward)

Critiques of Piaget's Theory

• Well-accepted contribution but with some flaws
• Children have unique schemas that guide their thought process
• Learning is an active process
• Piaget probably underestimated children's cognitive abilities
• Development may be more continuous, less abrupt
• Methods may be culturally biased creating differences in rate and sequence of development with learning
• When does cognitive development end?
• Postformal stage?

Cognitive Development - Aging

• Cognitive functions start to decline in the mid-seventies
• IQ decreases with age but can be avoidable
• Possible exception is the speed of processing
• The brain could efficiently function for 150 to 200 years
• This can happen if it were supported by other bodily systems
• Memory: Recall declines, but cued and recognition memory stay intact.
• Vocabulary and knowledge increase
• Neurons die but can continue to increase in complexity
• Dementia, e.g., Alzheimer's: occurs in less than 1% over 65, and about 20% over 80

Stages of Moral Development

• Morality: telling Right from wrong
• Kohlberg made three major stages of Moral Development
• Preconventional - focus on punishment and reward
• Conventional – focus on societal values
• Postconventional – focus on internal moral principles

Moral Development - Heinz Dilemma

• Woman near death with special kind of cancer in Europe
• It could be treated with a drug that doctors thought could save her
• It was a form of radium that a druggist in the same town recently discovered
• The drugs was expensive to make: druggist charged ten times what it cost to make
• He paid $200 for the radium and charged $2,000 for a small dose
• The sick woman's husband, Heinz, went to everyone he knew to borrow money
• Could only get about $1,000 which is half of what it cost. Heinz told the druggist his wife was dying, and asked that he sell cheaper or let him pay later. The druggist refused to allow this
• Heinz got desperate: he broke into the man's store to steal the drug for his wife.
• Should Heinz have done that and why?

Example Classifications Using Drug Dilemma

• More interested in people's reasoning than their actual answers
• Don't steal drug to avoid punishmen (Preconventional)
• Don't steal because stealing is against the law (Conventional)
• Postconventional: Don't steal drug because without the rule of law, society will descend into chaos (society needs order)

Challenges to Kohlberg's Theory

• Cultural bias - individualist vs collectivist cultures
• There is Gender bias - justice' vs. 'caring' orientations
• There is a low correlation with moral behavior
• Is Confounded with verbal intelligence

Social and Personal Development

• Differences in children's social and emotional reactivity reflect differences in temperament
• Early appearing and largely genetic
• Three major styles of temperament
  • Easy - 40% of kids exhibit this
  • Difficult - 10% of kids are defined as difficult
  • Slow-to-warmup - 15% of children are slow to warmup
• Stranger anxiety at 8-9 months

Attachment

• Attachments are strong emotional ties formed to one or more intimate companions
• Possible sensitive periods result in healthy interpersonal relationships which are likely biologically-rooted
• Adaptive!
• Bowlby (1969): Attachment is Necessary for normal social and emotional development

How Does Attachment Start?

• Behaviorists assumed children bonded with those that provided them nourishment
• Harlow's research with rhesus monkeys
• What if a hard wire object provides food, soft one gives nothing?
• Monkey's Attach to soft object in spite of not providing nourishment
• Reassuring physical contact played huge role in developing attachment

Strange Situation Test

• Strange situation test as tool developed by Ainsworth in 1978.
• This would test and show how behavior would change in a stressful situation
• Testing would be mainly with 10 to 24-month olds

Attachment Styles:

• Secure: Upset when caregiver leaves, happy when he or she returns
• Insecure-avoidant: indifferent when caregiver leaves and returns
• Insecure-anxious (or resistant): panic when caregiver leaves, mixed reaction on return
• Disorganized: inconsistent, confused reactions

Criticisms of Attachment Theory:

• Large cultural differences observed in studies
• Influence of temperament skews results
• Lack of reliability on the Strange Situation
• changing styles over brief periods
• Different styles used for mom vs dad (40% of infants)

The Achievement Gap

• Children from lower socioeconomic (SES) homes: score lower on tests, graduate at lower rates
• Lower SES parents spoke significantly less to their children relative to higher SES parents
• Study by Hart & Risley examined by progression of language in kids of various income levels
• By 3 years old, high SES children knew more than double the number of known words.
• Solutions?