ChapTer 3 Development Over the Life Span 113no longer believe there is a universal grammar because lan-
guages also vary grammatically around the world. Instead, they
say, language is a cultural tool, shaped by the world in which
children grow up.• Some models of language acquisition do not assume an innate
capacity at all; instead, they assume that children learn the
statistical probability that any given word or syllable will follow
another. Parental practices, such as recasting a child’s incorrect
sentence, also aid in language acquisition. It is likely, therefore,
that biological readiness and experience interact in the develop-
ment of language.
• Language acquisition begins in the womb, as even newborns can
distinguish the language their mother spoke during pregnancy
from an unfamiliar language. Infants are responsive to the pitch,
intensity, and sound of language, which may be why adults
in many cultures speak to babies in parentese, using higher-
pitched words and exaggerated intonation of vowels.
- At 4 to 6 months of age, babies begin to recognize the sounds
of their own language. They go through a babbling phase from
age 6 months to 1 year, and at about 1 year, they start saying
single words and using symbolic gestures, which continue to be
important for language, thinking, and problem solving. At age 2,
children speak in two- or three-word telegraphic sentences that
convey a variety of messages.
Cognitive Development
• Jean Piaget argued that cognitive development follows predict-
able stages as the child matures and that children’s thinking
changes and adapts through assimilation and accommodation.
- Piaget proposed four stages of cognitive development: senso-
rimotor (birth to age 2), during which the child learns object per-
manence; preoperational (ages 2 to 7), during which language
and symbolic thought develop, although the child remains ego-
centric in reasoning and has difficulty with some mental opera-
tions; concrete operations (ages 7 to 12), during which the child
comes to understand conservation; and formal operations (age
12 to adulthood), during which abstract reasoning develops.
• Today we know that the changes from one stage to another are
not as clear-cut as Piaget implied; development is more con-
tinuous and overlapping. Babies and young children have greater
cognitive abilities than Piaget thought, perhaps because of the
core knowledge they are born with. Young children are not al-
ways egocentric in their thinking; by the age of 4 or 5, they have
developed a theory of mind to account for their own and other
people’s behavior. And cultural practices affect the pace and
content of cognitive development.
Moral Development
• Developmental psychologists study how children learn to inter-
nalize standards of right and wrong and to behave accordingly.
This ability depends on the emergence of conscience and the
moral emotions of guilt, shame, and empathy.
• As a strategy for teaching children to behave, a parent’s use
of power assertion is associated with a child’s aggressiveness
and lack of empathy. Induction is associated with children who
develop empathy, internalize moral standards, and can resist
temptation. But all methods of discipline interact with the
child’s own temperament.
• The capacity of preschool children to delay gratification and
control their impulsive wishes or feelings is associated with the
development of internalized moral standards and conscience.
This ability is enhanced by mothers who use induction as a pri-
mary form of discipline.Gender Development
• Gender development includes the emerging awareness of gender
identity, the understanding that people are biologically male or
female regardless of what they do or wear, and gender typing,
the process by which boys and girls learn what it means to be
masculine or feminine in their culture.- Some individuals are born with intersex physical conditions,
living with the physical attributes of both sexes, and may even-
tually consider themselves to be transgender. Transsexuals feel
that they are male in a female body or vice versa; their gender
identity is at odds with their anatomical sex.
• universally, young children tend to prefer same-sex toys and
playing with other children of their own sex. Biological psycholo-
gists account for this phenomenon in terms of genes and prena-
tal androgens, which appear to provide a basis for gender-typed
play. - Cognitive psychologists study how children develop gender
schemas for the categories “male” and “female,” which in turn
shape their gender-typed behavior. Gender schemas tend to be
inflexible at first. Later they become more flexible as the child
cognitively matures and assimilates new information, if the
child’s culture promotes flexible gender schemas. Learning theo-
rists study the direct and subtle reinforcers and social messages
that foster the contents of gender typing.
• Gender development changes over the life span, depending on
people’s experiences with work and family life and larger events
in society and their culture.
adolescence
• Middle childhood (ages 6 to 12) is an important phase in which
children around the world begin to be assigned various respon-
sibilities. During these years, children go through adrenarche,
when the adrenal glands begin pumping out hormones that af-
fect brain development.
• Adolescence begins with the physical changes of puberty. In
girls, puberty is signaled by menarche and the development
of breasts; in boys, it begins with the onset of nocturnal emis-
sions and the development of the testes, scrotum, and penis.
Hormones produce secondary sex characteristics, such as pubic
hair in both sexes and a deeper voice in males.
• The adolescent brain undergoes a major pruning of synapses,
along with myelinization, which improves the efficiency of neu-
ral transmission and strengthens the connections between the
emotional parts of the brain and the reasoning prefrontal cortex.
These neurological changes may not be complete until age
25, which would help explain why the strong emotions of the