Child Development Fundamentals

A 2-year-old who throws food is usually running an experiment, not being defiant. Knowing that changes how you respond. Child development is the study of how children grow in body, thinking, feelings and language. You don't need a degree to use it. You need to know what is typical at each age, what to watch for, and how to adjust what you do.

The ages below are averages. Children vary, and a child who is early in one area may be late in another. For the milestones most children reach by a given age, the Centers for Disease Control and Prevention (CDC) publishes free checklists under its "Learn the Signs. Act Early." program.

What You Will Be Able to Do

• Name the four areas of development, and describe how they connect
• Describe what is typical for infants, toddlers, preschoolers and school-age children
• Match activities and expectations to a child's age
• Support learning through play, routines, language and scaffolding
• Notice a possible delay and share it the right way, without diagnosing

How Development Works

Development happens in four main areas, or domains. They all affect one another.

Physical skills split into two kinds. Gross motor skills use large muscles, as in walking and running. Fine motor skills use small, precise movements, as in grasping and writing.

Physical control also tends to move from the head downward, which is called cephalocaudal development. Babies control the head first, then sit, then stand.

Play is the main way young children learn. In play they try out ideas, practice movement, and work through feelings and friendships. Scheduled play time is not a break from learning. It is the learning.

Adults help most with scaffolding. Scaffolding means giving just enough support for a task a child can't quite do alone, then pulling back as they get better. You might hold a puzzle piece near the right spot, then later only point, and later just watch.

Routines matter at every age. Predictable days help children feel secure, which lowers anxiety and supports self-regulation, so there are fewer behavior problems.

Infants: Birth to 12 Months

Most babies start walking on their own around 12 months, but anywhere from about 9 to 15 months is typical, and some take a bit longer. The pincer grasp, which means picking up small items between thumb and forefinger, shows up around 7 to 9 months. From then on, anything small in reach can be a choking hazard.

Object permanence is the idea that things still exist when out of sight. It starts to develop around 4 to 8 months and becomes clear by about 9 months, when a baby looks for a dropped toy. Peek-a-boo works because of it.

Separation anxiety is distress when a trusted adult leaves. It often peaks between about 10 and 18 months, and it is a healthy sign of attachment.

In your daily care:

• Give supervised tummy time. It strengthens the muscles for rolling, sitting and crawling, and it helps prevent flat spots on the head.
• Respond to cries. You cannot spoil a baby, and responsive care builds trust.
• Talk all the time. Narrating a diaper change ("Now I'm lifting your feet") builds language, and early language exposure is strongly tied to later school success.
• Let a new baby warm up to you from a familiar adult's arms.

Toddlers: 1 to 3 Years

Toddlers have two big drivers: they can now move, and they want to do things themselves.

Physical. Walking gets steadier, then comes running, kicking, climbing, stacking blocks and scribbling. By about 3, many can pedal a tricycle and turn a doorknob.

Language. Words grow fast, and children vary widely. CDC's milestones, which at least 75 percent of children reach by the listed age, include putting two words together by 2 and saying about 50 words by 30 months. By 3, many speak in short sentences.

Thinking. Pretend play begins around 18 to 24 months, such as feeding a doll, and becomes more complex through the preschool years. Toddlers can follow one-step directions, then two-step ones.

Social-emotional. "No" and "mine" are normal. Tantrums come from strong feelings and low self-control. Parallel play is the main kind of play, which means children play next to each other, not with each other. It is typical of ages 2 to 3. Sharing is a skill that comes closer to age 3 to 4, so a 2-year-old who won't share is not being rude.

In your daily care:

• Childproof the room, because toddlers are fast and don't sense danger.
• Offer small choices: "The red cup or the blue cup?"
• Don't force sharing. Have duplicates, and help them take turns.
• Keep group time short. For 2-year-olds, about 5 minutes is plenty.
• Use short, clear words: "Feet on the floor."
• Read together often, and let them turn the pages.

Preschoolers: 3 to 5 Years

Physical. Children hop, catch a bounced ball, use scissors, and draw shapes and people. Most establish hand preference by about age 4. Most use the toilet on their own, though accidents still happen.

Thinking. They ask "why" all the time. Attention spans are longer, about 15 to 20 minutes for an activity they enjoy. Magical thinking is common, which means believing that a thought or wish can make something happen. A child may think they caused a parent's illness by being angry. Be alert to that.

Language and literacy. Emergent literacy means the early reading and writing skills children build before formal teaching, such as knowing that print has meaning and scribbling a "list." Support it by reading aloud, pointing out print, and having books and writing tools around.

Social-emotional. Cooperative play grows, with shared roles and stories. Friendships begin. Children can take turns and follow rules with reminders. Imaginary friends are normal. Fears, such as of the dark or dogs, are common.

In your daily care:

• Offer open-ended materials like blocks, art supplies, dress-up clothes, sand and water.
• Coach conflict instead of solving it: "Tell him what you want."
• Answer questions honestly, and look things up together.
• Build early math and reading through play, not worksheets.
• Give real jobs, like setting the table or watering plants.

School-Age Children: 5 to 12 Years

School-age children in care are usually in before- and after-school or summer programs.

Physical. Coordination improves, baby teeth fall out, and interest in sports grows. Some children begin puberty at around 10 to 12, and their need for privacy rises.

Thinking. Logic, planning and strategy develop. Children read independently and may have strong interests.

Social-emotional. Friends matter more, and so does comparing themselves with others. They want to feel good at things. Bullying and exclusion can appear.

In your daily care:

• Offer a mix of structured activities and free choice.
• Help with homework, but don't do it for them.
• Give leadership roles, and treat them as capable.
• Respect privacy for changing and bathroom use.
• Watch for bullying and exclusion, and step in.

Using Development Every Day

Planning. Before an activity, ask, "Can these children actually do this?" Offer the same activity at different levels. At the art table, a toddler scribbles, a preschooler draws a person and a school-ager works on a detailed scene. Follow children's interests. If they love bugs, build activities around bugs.

Expectations. Base your rules on what children can manage, and expect to repeat yourself. Young children need many repetitions.

Safety. Development changes risk. A child who just learned to climb needs closer watching, and what is safe for a 5-year-old, such as small building bricks, may be a choking hazard for a toddler. In mixed-age groups, keep small items out of the younger children's reach.

Families. Share progress: "She stacked six blocks today." Use development to explain behavior: "Biting is common at this age. Here's what we're doing." Don't compare children.

When You Have a Concern

You see children for hours each day, often in a group, so you may notice something first. Children vary, and one late milestone is not a sign of trouble. These are reasons to raise a concern:

• Not meeting several milestones for their age
• Very little eye contact or interest in people
• No babbling, pointing or gestures by around 12 months
• Few or no words by around 16 to 18 months, or no two-word phrases by age 2
• Hard to understand, or not speaking in sentences, well past the typical age
• Very stiff or very floppy muscles, or using one side of the body much more than the other
• Behavior that doesn't improve with consistent guidance

Warning: Losing skills at any age needs prompt attention. If a child who used to talk in sentences stops talking, or stops walking, write down what you observed and tell your supervisor the same day. The family should talk with the child's doctor soon.

Your role is to observe, document and share through the right channels. You never diagnose.

1. Write down what you see, with specific examples and dates.
2. Talk with your supervisor first.
3. Follow your program's process for talking with the family.
4. Share what you see, not what you think it means: "I've noticed Marcus doesn't turn when other children call his name," not "I think Marcus can't hear."
5. Be ready for mixed feelings. A family may be worried, upset or relieved.
6. Your director can point families toward their doctor and free local services.

Federal law, the Individuals with Disabilities Education Act (IDEA), provides early intervention for children under 3. Early help makes a real difference. A child under 3 who qualifies has an Individualized Family Service Plan (IFSP). A child age 3 or older who qualifies for special education has an Individualized Education Program (IEP), which is a legal document that lists goals, services and accommodations. If a child in your care has one of these plans, ask how you can support it. Keep it confidential.

Do not exclude a child because of a concern. Disability laws protect children in many programs, so involve your director.

Common Mistakes

Check Your Understanding

1. A 10-month-old cries hard at drop-off every day but is fine soon after. Her father is worried. What can you tell him?

Crying at separation is common at this age, and it shows she has a healthy bond with him. A short, steady goodbye routine helps. You can share how quickly she settles.

2. A 2-year-old sits beside another child with blocks and doesn't talk to him. His mother asks if he has a social problem. What do you say?

Playing side by side is typical at this age. It's called parallel play. You can tell her what you've seen, and that playing together develops over the next couple of years.

3. A child is struggling with a zipper. How do you scaffold it?

Don't do it for her. Start the zipper, and let her pull it up. Next time, show her how to line it up, and over time do less until she can do it alone.

4. A 2-and-a-half-year-old who used lots of words has stopped talking this month. What do you do?

Write down what you've seen, with examples and dates, and tell your supervisor the same day. Loss of skills needs prompt follow-up, and the family should talk with the child's doctor.

Key Takeaways

• Development covers physical, cognitive, social-emotional and language growth, and each affects the others
• Milestones are averages, and every child moves at their own pace within a range
• Play is how young children learn, and routines help them feel safe
• Scaffolding means giving just enough help, then stepping back
• Match activities, expectations and safety to what each child can do
• Observe, document and share through proper channels, and never diagnose
• Treat any loss of skills as urgent