CHAPTER 12 – Development Over The Lifespan
- Developmental psychology studies the process of aging. Questions about
the influence of nature and nurture, the existence of critical and sensitive
periods, continuity versus discontinuity, and stability versus change have
played a major role in guiding much developmental research.
- Cross-sectional designs compare people of different age groups at a
single point in time. A longitudinal design repeatedly tests the same age
group, as it grows older. A sequential design tests several groups at one
point in time and then again when they are older.
- Prenatal development involves the zygote, embryonic, and fetal stages.
- The 23 rd chromosome in a mother’s egg cell always is an X chromosome.
If the 23rdchromosome in the father’s sperm cell is an X, the child will be
genetically female (XX); if a Y, the child will be born genetically male (XY).
Maternal malnutrition, stress, illness, drug use, and environmental toxins
can cause abnormal prenatal development.
- Behavioural responses and learning begin during the fetal stage.
- Newborns have poor sensory acuity, but they can distinguish between
different visual patterns, speech sounds, odours, and tastes. They display
perceptual preferences, learn through classical and operant conditioning,
and may have a primitive capacity for imitation.
- Sensory, perceptual, and motor abilities have several different
developmental functions. Most rapidly improve during the first year of
life. Some newborn perceptual-motor responses temporarily decline
during the first few months after birth and then recover during the first
year of life.
- The cephalocaudal principle reflects the tendency for development to
proceed in a head-to-foot direction. The proximodistal principle states
that development begins along the innermost parts of the body and
continues toward the outermost parts.
- Experience is critical for normal development; without pattern vision,
visual acuity stalls at the newborn level but recovers to a large extent when vision is restored, although permanent deficits remain if the
deprivation occurs during the sensitive/critical period.
- According to Piaget, cognitive development depends on processes of
assimilation and accommodation, and occurs in 4 stages: sensorimotor,
pre-operational, concrete operational, and formal operational.
- Although the general cognitive abilities associated with Piaget’s 4 stages
occur in the same order across cultures, children acquire many cognitive
skills at an earlier age than Piaget believed. Vygotsky emphasized that
cognitive development occurs in a sociocultural context. Each child has a
zone of proximal development, reflecting the difference between what a
child can do independently and what the child can do with assistance
- Information-processing capacities improve with age. Older children
search for information more systematically, process it more quickly, and
display better memory.
- Children begin to develop a theory of mind (beliefs about another
person’s knowledge, feelings, intentions, etc.) around 3-4 years of age.
- Erikson proposed that personality development proceeds through 8
major psychosocial stages. Each stage involves a major crisis, and the
way we resolve it influences our ability to meet the challenges of the next
- Temperament reflects a biologically based pattern of reacting emotionally
and behaviourally to the environment. Extreme temperamental styles in
infancy and childhood can predict some aspects of functioning years
- Infant-caretaker attachment develops in 3 phases, and infants experience
periods of stranger and separation anxiety. Secure attachment is
associated with better developmental outcomes in childhood and
adolescence than insecure attachment. For most children, daycare does
not disrupt attachment.
- Parenting styles vary along dimensions of warmth-hostility and
restrictiveness-permissiveness. The children of authoritative parents
generally display the best developmental outcomes. Gender identity
begins to form early in childhood, and socialization influences children’s
acquisition of sex-role stereotypes.- Divorce disrupts children’s psychological adjustment in the short term,
and for some children and adolescents, is associated with a long-term
pattern of maladjustment.
- Kohlberg proposed that moral reasoning proceeds through 3 levels. Pre-
conventional moral judgments are based on anticipated rewards and
punishments. Conventional morality is based on conformity to social
expectations, laws, and duties. Post-conventional moral judgments are
based on well thought out moral principles. Critics argue that the model
contains cultural and gender biases.
- Moral behaviour is governed by many factors, including learning
(rewards, punishments, and modeling), temperament, attachment, and
emotional development. Activity in the prefrontal cortex has been related
to moral behaviour.
- In Western cultures, puberty marks the onset of adolescence. Hormones
that steer puberty also can affect mood and behaviour. Generally, early
maturation is a more positive experience for boys than it is for girls.
- During adolescence, neural restructuring is especially prominent in the
prefrontal cortex and the limbic system, regions that play a key role in
planning and coordinating behaviours that satisfy motivational goals,
emotional urges, and moral decisions.
- Young adults are at the peak of their physical, sexual, and perceptual
functioning in their 20s.
- Declines in physical processes (perception, bone density, basic metabolic
rate, flexibility, etc.) begin in the 30s, and become more pronounced in
late adulthood, but an active lifestyle, good nutrition, and a positive
attitude can offset many age-related declines.
- Improvements in information-processing processes (speed, memory)
foster increases in abstract reasoning during adolescence. However,
many teens and adults continue to struggle on formal operational tasks;
while some people frequently use abstract reasoning, others rarely do so.
- Information-processing capacities decline steadily after reaching one’s
30s. However, longitudinal data show that many intellectual abilities do
not begin to decline reliably until late adulthood.
- Cross-sectional studies suggest that wisdom increases with age. - Erikson proposed that intimacy versus isolation, generativity versus
stagnation, and integrity versus despair are the main crises of early,
middle, and late adulthood.
- Young adolescents often show egocentrism in their social thinking. The
search for identity is a key task of adolescence. With age, teens who have
not experienced an identity crisis become more likely to do so, and most
resolve it successfully.
- During adolescence, peer relationships become more important and
intimate. Most teens maintain good relations with their parents.
- In North America, the most important criterion for a transition into
adulthood is becoming a responsible, independent person. In traditional
cultures, marriage is a common marker of this transition.
- In general, married people tend to be happier and live longer.
- Premarital cohabitation is associated with a higher risk of marital divor