Chapter 3Human Development

Prenatal Development Occurs

in Three Stages • Zygote stage (lasts two weeks):

• Embryonic stage (lasts from week 3 to week 8)

• Fetal stage (lasts from week 9 until birth)

Prenatal Development Occurs

in Three Stages • Zygote stage (lasts two weeks):

– The sperm fertilizes the egg and forms a new cell—the zygote.

– The zygote travels down the fallopian tubes to embed itself in the wall of the uterus.

Prenatal Development Occurs

in Three Stages • Embryonic stage (lasts from week

3 to week 8):

• When the zygote embeds itself in the uterine wall, this living tissue is called an embryo.

Prenatal Development Occurs

in Three Stages

Fetal stage (lasts from week 9 until birth):

• The last and longest stage in prenatal development in which tremendous growth occurs.

The Fetus Can Be Harmed by Parental and Environmental

Factors

– Parental age and maternal nutrition• The ages of both the mother and the

father can affect prenatal development.

– Harmful environmental agents• Teratogens: In Greek this word means

“monster maker”—any disease, drug, or other noxious agent.

A Child’s Brain Grows at an Immense Rate

The brain of an 8-month-old human fetus:• Has more than twice as many neurons as an

adult brain (Kolb, 1989).• Produces new neurons at a rate of hundreds of

thousands per minute.

• Early neural development results in the brain’s weight ballooning.

• Most added mass is due to the growth of new dendrites and the myelin sheath around axons.

Neural Network Growth During Infancy

Physical Growth and Motor Development Occur Together

• During year 1 the body almost triples in weight and increases in length by about one-third.

• In North America, infants:• Lift their heads at 2 months,• Sit up without support at 6 months, and• Walk by the end of the first year.

Physical Growth and Motor Development Occur TogetherNewborns have a number of reflexes.

– A reflex is an automatic, involuntary response to sensory stimuli.

Attachment

• Attachment: the strong emotional bond a young child forms with its primary caregiver – An important ingredient in developing

attachment is receiving contact comfort.

Attachment

• Attachment bonds develop in stages:- 3–6 months: Clear preference for primary

caregivers but do not become upset when separated from them

- 7–9 months: An attachment bond forms toward a specific caregiver, and children become extremely upset following separation (separation anxiety). Children develop a fear of strangers (stranger anxiety).

Attachment– Individual differences in attachment style

develop as infants interact with their parents

• Secure attachment: belief that one is worthy of others’ love and that people are trustworthy

• Insecure attachment: belief that one is unworthy of others’ love and that people are untrustworthy

• Securely attached children find it easier to form satisfying relationships with others than those with insecure attachment.

Influences on Attachment Style – Parenting style

• Parents who are responsive to their children’s emotional needs and provide sufficient contact comfort tend to foster secure attachment.

– Temperament • Infants with an easygoing temperament often

foster positive parental reactions and these children tend to develop a secure attachment, while children with a difficult temperament may foster negative parental reactions and develop an insecure attachment.

– Culture• Collectivist cultures are more likely to foster

secure attachment than individualist cultures.

Possible Causes of Children’s Attachment Style

Children Can Handle Parental Separation Under Certain

Conditions • Day care and attachment

– A number of studies have found children who are in full-time daycare to tend toward less secure attachment.

– However, meta-analytic research found no overall differences in attachment between children who stayed home and those who attended day care.

Children Can Handle Parental Separation Under Certain

Conditions • Divorce is a better predictor of adult

function than attachment

– A 23-year longitudinal study of more than 17,000 British infants found that parental divorce had a moderate, long-term negative impact on the mental health of about 12 percent of the children after they grew up.

Self-Concept Is the Primary Social Achievement of Childhood

• Self-concept: the “theory” or “story” a person constructs about herself or himself through social interaction.

• Self-awareness: a psychological state where an individual takes himself or herself as an object of attention. Once self-awareness develops at 18 months, a child begins to develop a self-concept.

Self-esteem

• Self-esteem stability:

– Is relatively low during childhood,– – Increases throughout adolescence

and young adulthood, and

– Declines during midlife and old age.

Children Learn the “Right Way” to Think about Gender

• Gender is constantly changing and being redefined. – Behaviors or interests considered

masculine in one culture may be defined as feminine in others.

Children Learn the “Right Way” to Think about Gender

Gender identity: the knowledge that one is a male or a female and the internalization of this fact into the self-concept

– Shortly after children develop self-awareness they begin to develop their gender identity.

– – Gender identity is one of the basic elements

in self-concept.

Erikson’s Stages

• Developing a sense of trust versus mistrust is the crisis of the first psychosocial stage (birth to 1 year)

• Developing a sense of autonomy versus shame and doubt is the crisis of the second psychosocial stage (1–2 years)

• Developing a sense of initiative versus guilt is the crisis of the third psychosocial stage (3–5 years)

Erikson’s Stages• Developing a sense of industry vs.

inferiority is the crisis of the fourth stage (6-12 years)

• Developing a sense of identity versus role confusion is the crisis of the fifth stage (13–18 years)

Erikson’s Stages

• Developing a sense of intimacy versus isolation is the crisis of the sixth stage (19–45 years)

• Developing a sense of generativity versus stagnation is the crisis of the seventh stage (46–65 years)

• Developing a sense of integrity versus despair is the crisis of the eighth and last stage (66 years and up)

Piaget’s Theory of Cognitive Development - Four Stages

• Jean Piaget contended that cognitive development occurs as children organize their structures of knowledge to adapt to their environment.

• A schema is an organized cluster of knowledge that people use to understand and interpret information.

Piaget’s Theory of Cognitive Development - Four Stages

• Acquisition of knowledge occurs through the complementary processes of assimilation and accommodation.

– Assimilation: the process of absorbing new information into existing schemas

– Accommodation: the process of changing existing schemas to absorb new information

Piaget’s Stages • Sensorimotor stage (birth–2 years):

– experience the world through actions (grasping, looking, touching, and sucking) • One of the major accomplishments at this stage is

the development of object permanence.

• Preoperational stage (2–6 years):– represent things with words and images

but having no logical reasoning

Piaget’s Stages • Concrete operational stage (7–11

years):– think logically about concrete events;

understanding concrete analogies and performing arithmetic operations

• Formal operational stage (12 years–adulthood): – develop abstract reasoning

The Three-Mountains Problem

Conservation of Liquid, Mass, and Number—Liquid

Conservation of Liquid, Mass, and Number—Mass

Conservation of Liquid, Mass, and Number—

Number

Some of Piaget’s Conclusions Have Been Questioned

• Development may be less “stagelike” than he proposed.

• Children may achieve capabilities earlier than he thought.

• All adults may not reach formal operational thought.

Evaluating Piaget• Despite criticisms, most developmental

psychologists agree that Piaget has generally outlined:– An accurate view of many of the significant

changes that occur in mental functioning with increasing childhood maturation; and

– That children are not passive creatures merely being molded by environmental forces, but that they are actively involved in their own cognitive growth.

Vygotsky’s Theory of Cognitive Development

• Private speech and internalization According to Vygotsky, learning occurs

through the social instrument of language.- Children listen to people, observe their actions, and

then internalize this knowledge and make it their own through private speech.

• Zone of proximal development In assessing cognitive development,

Vygotsky maintained that you need to identify children’s zone of proximal development (ZPD). - The ZPD is the cognitive range between what a child

can do on her or his own and what the child can do with the help of adults or more-skilled children.

The Information-Processing Approach

• The information-processing approach contends that a number of important changes occur in children’s information-processing system that directly affect their ability to learn.

• The increase in information-processing speed appears to be due to the maturation of the brain.

Adolescence

• Adolescence, as a stage in life, is a relatively recent phenomenon. – Most societies have always viewed young

people as needing instruction and time to develop.

– In North American culture, the length of the adolescent period has gradually increased over the past 40 years, partly due to our society’s emphasis on attending college.

Figure 3-6 Median Age at First Marriage, United

States

Source: Fields, Jason. (2001). American’s families and living arrangements: March 2000 (Current Population Reports, P20-537). Washington, DC: U.S. Government Printing Office. Available online at http://www.census.gov/prod/2001pubs/p20-537.pdf.

Heightened Self-Consciousness Is a Hallmark of Adolescence

• imaginary audience: belief that other people are constantly focused on their thoughts, feelings, and behavior.

• personal fable: the tendency for teenagers to believe that no one has ever felt or thought as they do.

• Despite these self-focused tendencies, in most areas of their lives, adolescents are as well adjusted as children and adults.

Parenting and Job Responsibilities Often Provide Conflicts

• Most adults devote tremendous time and effort to pursuing careers and/or raising children. Despite a historical shift toward gender equity:

– Women are much more likely than men to receive mixed societal messages concerning their ability to juggle these dual responsibilities.

– Women’s fear of conflict between occupational and family goals is less of an issue among Black women than White women.

Parenting and Job Responsibilities Often Provide Conflicts

• Modern society has failed to adequately encourage men to expand their responsibilities within the household.

• When families have actively involved and caring fathers, everyone benefits.

Certain Intellectual Abilities Increase While Others Decrease as

We Age

• Despite the physical toll of aging, mental skills remain fully functional throughout most of adult life.

• Around the age of 65, some adults experience a slight decline in certain intellectual abilities.

Certain Intellectual Abilities Increase While Others Decrease as

We Age

• Older adults’ reduced neural processing speed does not adversely affect their ability to:

– Reason through everyday problems, – Understand mathematical concepts,

or – Learn new information.