225. CCA Study Notes: Human Growth and Development Across the Lifespan

The Big Picture

People change throughout life. Their bodies grow, their abilities develop, and their relationships and responsibilities change over time.

Growth refers to increases in physical size and weight. Development means maturing toward adulthood through physical changes and increasing abilities.

Each stage of life also has developmental tasks. A developmental task is an activity that must be mastered during a stage of development.

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Course Notes: Key Ideas You Need to Know

Growth, Development, and Developmental Tasks

Growth means an increase in physical size and weight.

Development refers to maturation toward adulthood. It usually involves physical changes along with greater ability and functioning.

A developmental task is something that must be mastered during a particular stage of development.

Infancy: Birth to 1 Year

Infancy is the first year of life. Physical, psychological ⓘ, and social growth happen rapidly during this stage.

Major developmental tasks include:

• learning to walk
• learning to eat solid foods
• beginning to talk and communicate
• beginning emotional relationships with primary caregivers and siblings
• developing more stable sleeping and feeding patterns

The first 28 days after birth are called the neonatal period. A baby during this period is a newborn, also called a neonate.

Newborn Growth and Appearance

An average newborn:

• measures 48 to 53 cm, or 19 to 21 in., in length
• weighs 3 200 to 3 600 g, or 7 to 8 lb., at birth

Genetics, ethnicity, poverty, and lack of prenatal care are among the factors associated with differences in birth weight, length, and head circumference.

Birth weight usually doubles by 5 to 6 months and triples by the first birthday.

A newborn’s head is large compared with the rest of the body. The arms and legs look short compared with the trunk, and the abdomen is large and round. Skin and eye colour vary and may change during the first year.

Senses and Early Movement

The infant’s central nervous system is still developing. Early movements lack coordination and purpose.

Infants can see at birth, although their vision is unclear. They are attracted to patterns and later show a preference for colours.

Hearing works well. Loud sounds can startle infants, while soft sounds can soothe them. Infants respond more often to higher-pitched voices than lower-pitched voices.

Touch, smell, and taste are also well developed.

Newborn Reflexes

A reflex is an involuntary ⓘ movement in response to a stimulus ⓘ. Newborn reflexes gradually decline and disappear as the central nervous system develops.

• Moro reflex, or startle reflex: A loud noise or sudden movement causes the infant to throw the arms apart, extend the legs, and move the head backward.
• Rooting reflex: Touching the cheek near the mouth causes the infant to turn toward the touch. This reflex helps guide the mouth toward the nipple for feeding.
• Sucking reflex: Touching the cheeks or sides of the lips produces this reflex.
• Grasping reflex: Stimulating the palm causes the fingers to close around an object. It begins to decline around the second month and disappears by the third month.

The Moro and rooting reflexes disappear around 4 months.

Sleep and Movement Changes

During the first few weeks, infants sleep most of the time. They wake when hungry and often fall asleep after eating.

As infants grow, the time between feedings becomes longer. They spend more time awake and less time sleeping.

Movement also changes. Early movements are mostly involuntary and uncoordinated. As the central nervous system and muscles develop, movements become more voluntary, specific, and coordinated.

Milestones During the First Year

Newborn: The infant cannot hold the head up. During the first 6 months, the diet is mainly breast milk or formula milk.

1 month: The infant can hold the head up when held and lift and turn the head while lying on the stomach.

2 months: The infant can smile and follow moving objects with the eyes.

3 months: The infant can raise the head and shoulders while lying on the stomach, sit with support briefly, and hold a rattle.

4 months: The infant is usually able to roll over and sit with support. Some sleep through the night. The infant can hold objects with both hands, put objects in the mouth, and babble when spoken to. The Moro and rooting reflexes disappear.

5 months: The infant can grasp objects and play with the toes. Teeth begin to appear. Solid foods are usually introduced between 5 and 7 months. A doctor or nurse advises dietary changes.

6 months: The infant usually has two lower front teeth, begins chewing and biting finger foods, can hold a bottle, and can sit alone briefly.

7 months: Upper teeth begin to appear. The infant responds to their name, may say “dada” and “mama,” and begins to fear strangers.

8 months: The infant may stand while holding onto something and responds to the word “no.” Dressing and diaper changes are often disliked.

9 months: The infant usually crawls. More upper teeth appear. Finely chopped foods are introduced during the ninth and tenth months.

10 months: Most infants walk while holding onto furniture. They understand several words but say only a few. They use pointing and gestures to show what they want and smile at themselves in a mirror.

11 months: The infant may begin taking a few steps.

1 year: Many infants begin walking. They can hold a cup, know more words, say and gesture “no,” and try to copy words spoken by adults. They usually play alone with their own toys, known as solitary play. Most can eat table foods.

Toddlerhood: 1 to 3 Years

Toddlerhood covers ages 1 to 3 years. Physical growth slows compared with infancy.

Major developmental tasks include:

• tolerating separation from the primary caregiver
• gaining bowel and bladder control
• using words to communicate
• becoming less dependent on the primary caregiver

Toddlers have a strong need for independence. Walking, greater coordination, and curiosity help them explore their environment. By age 3, a toddler can run, jump, climb, ride a tricycle, and walk up and down stairs.

Hand Skills and Self-Feeding

Hand coordination improves during toddlerhood.

Toddlers move from eating with their fingers to using a spoon. They drink from cups and develop skills such as scribbling, stacking blocks, stringing beads, and turning book pages.

A preference for the right or left hand appears during the second year.

Toilet Training

Toilet training is an important developmental task.

Children need enough physical and psychological readiness because bowel and bladder control depend on central nervous system development.

Bowel control usually develops first because bowel movements happen less often than urination. Bowel training may be completed around 2.5 years.

Daytime bladder control develops before nighttime bladder control. Bladder training may be completed around age 3.

Language and Play

Toddler speech becomes clearer, and vocabulary grows. Children learn words by copying others and understand more words than they use.

Toddlers can form two- or three-word sentences. By age 3, children should be able to speak in short sentences.

At age 2, children commonly engage in parallel play. They play beside other children rather than directly with them.

Toddlers are often possessive and have not yet developed a clear understanding of sharing.

Independence, Tantrums, and Separation

Temper tantrums and saying “no” are common during toddlerhood. A tantrum can happen when the child feels that independence is being challenged.

Toddlers also work on tolerating separation from a primary caregiver. They explore farther away but often return to the caregiver when uncomfortable, frustrated, or hurt.

When the caregiver remains consistently available when needed, the child learns security and becomes better able to tolerate short separations.

Preschool: 3 to 5 Years

The preschool years cover ages 3 to 5. Children become taller while gaining relatively little weight. They become thinner, more coordinated, and more graceful than toddlers.

Important developmental tasks include:

• communicating and understanding others more effectively
• performing self-care activities
• learning about gender differences
• learning right from wrong
• learning to play with other children
• developing family relationships

The 3-Year-Old

Three-year-olds have greater physical coordination. They can walk on tiptoe, balance briefly on one foot, run, jump, and climb.

Self-care skills increase. They can put on shoes, dress themselves, manage buttons, wash their hands, and brush their teeth with help. They can also feed themselves.

Most 3-year-olds know about 1 000 words. Their sentences usually contain three or four words.

Play becomes more social. Three-year-olds can play with other children instead of only beside them. With adult encouragement, they can share and take turns.

Imagination is strong. Make-believe play and imaginary friends are common. Children at this age may sometimes confuse fantasy with reality.

They also begin to understand past, present, and future, although words such as “yesterday” and “tomorrow” may still confuse them.

Short separations from primary caregivers become easier to tolerate.

The 4-Year-Old

Four-year-olds can hop, skip, throw and catch a ball, draw faces, copy a square, and try to print letters.

They can bathe with some help and usually manage toileting with help.

Vocabulary increases to about 1 500 words. Four-year-olds continue asking many questions and often tell longer, more complex stories.

Hand and finger coordination continue improving. They enjoy crafts, building, drawing, dress-up, and imitating adults.

Their imagination remains vivid, but they become better at separating fantasy from reality.

They become more social and often enjoy playing in groups of two or three. Close friendships also begin to develop.

Curiosity about sexuality may increase. Questions about babies and differences between genitals are common.

The 5-Year-Old

Five-year-olds continue gaining coordination. They can jump rope, skate, tie shoelaces, dress, and bathe.

They can copy diamond and triangle shapes, print some letters and numbers, and print their first names.

Vocabulary reaches about 14 000 words, and sentences contain about six to eight words. Their questions become more meaningful, and they want explanations for unfamiliar terms.

Five-year-olds show greater awareness of rules and often want to do things correctly. They tend to show more independence, responsibility, and pride in their accomplishments.

They enjoy simple number and word games. Rules become important during play, although they may sometimes cheat to win.

They generally tolerate brothers and sisters better and may become protective of younger children.

Middle Childhood: 6 to 8 Years

Middle childhood covers ages 6 to 8. School, peers, games, and learning become increasingly important.

Developmental tasks include:

• developing physical and social skills for games
• learning to get along with peers ⓘ
• learning behaviours and attitudes considered typical for one’s gender
• learning basic reading, writing, and arithmetic
• developing a conscience and morals
• developing a positive attitude toward oneself

The 6-Year-Old

Between the sixth and seventh birthdays, a child grows about 5 cm, or 2 in., and gains about 1 to 3 kg, or 2.5 to 6.5 lb.

Baby teeth are lost, and permanent teeth begin appearing.

Six-year-olds are highly active. They can run, jump, skip, hop, and ride a bicycle.

They enter Grade 1 and become more involved with school and other children. Many begin to prefer playing with children of the same gender and may develop a best friend.

Vocabulary reaches about 16 500 words. Children know the alphabet and begin reading and spelling.

Their ability to express thoughts and feelings also improves.

The 7-Year-Old

Seven-year-olds grow about 5 cm, or 2 in., during the year.

An average 7-year-old weighs about 22 to 25 kg, or 49 to 55 lb., and measures about 119 to 124 cm, or 47 to 49 in., tall.

Hand coordination improves enough for cursive writing.

Seven-year-olds tend to become quieter, more serious, and more concerned about being liked. They become more aware of their bodies and of how others react to them.

They may be sensitive to teasing and criticism.

Most enjoy school, reading, and learning, although they may worry about marks and what teachers think. They can also tell time.

Play often includes swimming, biking, collecting and trading objects, puzzles, video games, and games with rules.

The 8-Year-Old

Eight-year-olds enter Grade 3. Height and weight continue increasing, more permanent teeth appear, and movement becomes faster and more graceful.

Peer groups become especially important. Acceptance and belonging affect feelings of love, belonging, and self-esteem.

Eight-year-olds generally get along with adults, but peer opinions, interests, and group activities become increasingly important.

They can help with household tasks such as vacuuming, cooking, and yardwork.

Curiosity about science, history, and other places grows. School provides important opportunities for learning and social interaction with peers.

Late Childhood: 9 to 12 Years

Late childhood, also called preadolescence, covers ages 9 to 12. It sits between childhood dependence and adolescence.

Developmental tasks include:

• becoming more independent of adults
• developing and maintaining friendships
• understanding physical, psychological, and social gender roles
• developing moral and ethical behaviour
• increasing muscular strength, coordination, and balance
• learning how to study

Boys grow about 2.5 cm, or 1 in., each year. Girls grow about 5 cm, or 2 in., each year.

Boys gain about 1.8 kg, or 4 lb., each year. Girls gain about 2.3 kg, or 5 lb., each year.

Girls are usually taller than boys during late preadolescence. Most permanent teeth have appeared by this stage.

Physical and Social Changes

Body movements become more coordinated and graceful. Muscular strength and physical skills increase.

Changes related to approaching puberty also begin.

In girls, the pelvis becomes broader, body fat appears on the hips and chest, and breasts begin developing.

Boys show fewer outward signs of sexual maturity at this stage, although the genital organs begin to grow.

Peer groups strongly influence attitudes and behaviour. Children may increasingly question adult rules and notice adults’ mistakes and weaknesses. Disagreements with parents may increase, although parents remain important.

Children at this age need factual information about sex because information shared among friends may be incomplete or inaccurate. With a parent’s permission, questions should receive honest and complete answers in language the child understands.

Adolescence: 12 to 18 Years

Adolescence is a period of rapid physical growth and psychological and social maturity. It begins with puberty.

Puberty is the period when reproductive organs begin functioning and secondary sex characteristics ⓘ appear.

Girls generally experience puberty between ages 10 and 14. Most boys experience puberty between ages 12 and 16.

Knowing or questioning sexual orientation commonly occurs during this stage of development.

Developmental tasks during adolescence include:

• accepting changes in the body and appearance
• developing relationships with people of the same age
• exploring gender identity
• becoming more independent from parents and adults
• developing morals, attitudes, and values
• increasing use of social media and electronic communication to interact with peers

Puberty in Girls

Menarche means the beginning of menstruation. It marks the onset of puberty in girls.

Secondary sex characteristics include:

• increased breast size
• pubic and axillary ⓘ hair
• slight deepening of the voice
• widening and rounding of the hips

Puberty in Boys

Male reproductive organs begin increasing in size during late childhood and continue growing during adolescence.

Ejaculation, the release of semen, signals the onset of puberty in boys.

Involuntary nocturnal emissions, also called wet dreams, may occur during sleep.

Secondary sex characteristics include:

• facial hair
• pubic and axillary hair
• hair on the arms, chest, and legs
• a deeper voice
• increased neck and shoulder size

Adolescent Growth

A major growth spurt occurs during adolescence.

Boys grow about 10 to 41 cm, or 4 to 16 in., and gain about 7 to 27 kg, or 15 to 60 lb.

Boys usually stop growing between ages 18 and 21, although some continue until about age 25.

Girls grow about 5 to 23 cm, or 2 to 9 in., and gain about 7 to 23 kg, or 15 to 50 lb.

Girls usually stop growing between ages 17 and 18, although some continue until about age 21.

Uneven growth of muscles and bones can cause temporary awkwardness and clumsiness. Coordination improves as muscle and bone growth become more balanced.

Body Image and Physical Changes

Physical changes can be difficult for adolescents to accept. Concerns may involve breast development, genital size, height, or weight.

Many adolescents, especially girls, worry about their weight. Some may diet because they think they weigh too much, and some may develop eating disorders.

Emotional and Social Development

Adolescents may experience intense and rapidly changing emotions. Emotional control generally improves later in adolescence.

Older adolescents, ages 15 to 18, may still experience strong sadness or depression but become better able to control when and where emotional reactions occur.

Independence from adults becomes increasingly important. Teenagers learn to make decisions and act responsibly with less adult supervision.

Logical thinking and reasoning also increase. Adolescents often develop strong opinions, although judgement and reasoning are not always sound. Parents still provide guidance, discipline, and emotional and financial support.

Peers become increasingly important. Adolescents often prefer spending time with friends and may seek advice from peers or adults other than their parents.

Identity, Relationships, and Future Plans

Appearance, clothing, hairstyles, friendships, social activities, sports, clubs, electronic communication, and dating may become important parts of adolescent life.

Dating often begins during adolescence, although the age varies.

Adolescents may also face difficult decisions involving sexual activity and electronic communication. Images of themselves sent through an electronic communication network have a high likelihood of being misused.

Adolescents also begin thinking about careers and life after high school. Interests, talents, and skills influence choices involving further education or work.

Developing morals, values, and attitudes is another major developmental task. Family, peers, culture, religion, school, television, and movies can influence these areas.

Young Adulthood: 18 to 40 Years

During young adulthood, psychological and social development continue. Physical growth is limited because adult height has usually been reached and body systems are fully developed.

Developmental tasks include:

• choosing further education and a career
• selecting a partner
• learning to live with a partner
• becoming a parent and raising children
• developing a satisfactory sex life

Education and Work

Education and occupation are closely connected. Many jobs require specific knowledge and skills, so educational needs depend on career choices.

Employment supports economic independence and the ability to support a family.

Partnerships and Family Life

Young adults may marry, remain single, or live in common-law relationships.

Partners need to adjust habits, routines, household responsibilities, meals, and leisure activities to meet each other’s needs.

Successful partnerships require problem-solving, shared decisions, common goals, and open and honest communication.

Sexual needs and preferences vary among couples. Understanding and accepting a partner’s needs supports an intimate relationship.

Some couples have children, while others do not.

Some pregnancies are unplanned, while other couples plan whether and when to have children. Couples of any gender who want children but have difficulty having them may choose adoption, in vitro fertilization ⓘ, donor sperm, or surrogacy ⓘ.

Couples who decide to raise children need to agree on child-rearing and discipline and adjust to the time, energy, and attention that children require.

Middle Adulthood: 40 to 65 Years

Middle adulthood covers ages 40 to 65.

For some people, this period brings greater stability and more time after children become adults. Others face divorce, aging parents, adult children returning home, or caring for grandchildren.

Developmental tasks include:

• adjusting to physical changes
• having grown children
• developing leisure activities
• relating to and possibly caring for aging parents

Physical Changes

Some physical changes develop gradually.

Energy and endurance begin decreasing. Metabolism and physical activity may slow, making weight control more difficult.

Wrinkles and grey hair can appear. Changes in vision and hearing can also occur.

In people with female genitalia, menopause usually occurs between ages 42 and 55. Menstruation stops, the ovaries stop producing eggs and secreting hormones, and pregnancy is no longer possible.

Changing Family Roles

Adult children may leave home for school, work, marriage, or families of their own.

Parents adjust to letting adult children live independently while remaining available for emotional support.

With fewer parenting demands, some adults gain more leisure time. Hobbies, volunteer work, and clubs can become important sources of enjoyment.

Some middle-aged adults also care for aging parents and cope with their parents’ deaths.

Late Adulthood: 65 Years and Older

Late adulthood begins around age 65.

Normal physical aging happens in everyone, although the rate and degree of change differ from person to person.

Lifestyle, general health, exercise, stress, environment, and heredity affect some age-related changes.

Normal aging does not automatically mean losing health or quality of life.

Developmental tasks include:

• adjusting to decreased physical strength and loss of health
• adjusting to retirement and lower income
• coping with the death of a partner
• developing new friendships and relationships
• preparing for one’s own death