Chapter 13: Physical Development in Early Childhood

Chapter 13 Learning Objectives

  • Summarize the overall physical growth
  • Describe the changes in brain maturation
  • Describe the changes in sleep
  • Summarize the changes in gross and motor skills
  • Describe when a child is ready for toilet training
  • Describe sexual development
  • Identify nutritional concerns

Overall Physical Growth

Children between the ages of two and six years tend to grow about 3 inches in height and gain about 4 to 5 pounds in weight each year. Just as in infancy, growth occurs in spurts rather than continually. According to the Centers for Disease Control and Prevention (2000), the average 2-year-old weighs between 23 and 28 pounds and stands between 33 and 35 inches tall. The average 6-year-old weighs between 40 and 50 pounds and is about 44 to 47 inches in height. The 3-year-old is still very similar to a toddler with a large head, large stomach, short arms, and legs. By the time the child reaches age 6, however, the torso has lengthened, and body proportions have become more like those of adults.

This growth rate is slower than that of infancy and is accompanied by a reduced appetite between the ages of 2 and 6. This change can sometimes be surprising to parents and lead to the development of poor eating habits. However, children between the ages of 2 and 3 need 1,000 to 1,400 calories, while children between the ages of 4 and 8 need 1,200 to 2,000 calories (Mayo Clinic, 2016a). 

Brain Maturation

Brain weight: The brain is about 75 percent of its adult weight by three years of age. By age 6, it is at 95 percent of its adult weight (Lenroot & Giedd, 2006). Myelination and the development of dendrites continue to occur in the cortex and as it does, we see a corresponding change in what the child is capable of doing. Greater development in the prefrontal cortex, the area of the brain behind the forehead that helps us to think, strategize, and control attention and emotion, makes it increasingly possible to inhibit emotional outbursts and understand how to play games.

Understanding the game, thinking ahead, and coordinating movement improves with practice and myelination.

Growth in the Hemispheres and Corpus Callosum: Between ages 3 and 6, the left hemisphere of the brain grows dramatically. This side of the brain or hemisphere is typically involved in language skills. The right hemisphere continues to grow throughout early childhood and is involved in tasks that require spatial skills, such as recognizing shapes and patterns. The corpus callosum, a dense band of fibers that connects the two hemispheres of the brain, contains approximately 200 million nerve fibers that connect the hemispheres (Kolb & Whishaw, 2011). The corpus callosum is illustrated in Figure 4.2.

Figure 4.2

The corpus callosum is located a couple of inches below the longitudinal fissure, which runs the length of the brain and separates the two cerebral hemispheres (Garrett, 2015). Because the two hemispheres carry out different functions, they communicate with each other and integrate their activities through the corpus callosum. Additionally, because incoming information is directed toward one hemisphere, such as visual information from the left eye being directed to the right hemisphere, the corpus callosum shares this information with the other hemisphere. 

The corpus callosum undergoes a growth spurt between ages 3 and 6, and this results in improved coordination between right and left hemisphere tasks. For example, in comparison to other individuals, children younger than 6 demonstrate difficulty coordinating an Etch A Sketch toy because their corpus callosum is not developed enough to integrate the movements of both hands (Kalat, 2016).

Motor Skill Development

Early childhood is the time period when most children acquire the basic skills for locomotion, such as running, jumping, and skipping, and object control skills, such as throwing, catching, and kicking (Clark, 1994). Children continue to improve their gross motor skills as they run and jump. Fine motor skills are also being refined in activities, such as pouring water into a container, drawing, coloring, and buttoning coats and using scissors. The table 1 highlights some of the changes in motor skills during early childhood between 2 and 5 years of age. The development of greater coordination of muscle groups and finer precision can be seen during this time period. Thus, average 2-year-olds may be able to run with slightly better coordination than they managed as a toddler, yet they would have difficulty peddling a tricycle, something the typical 3-year-old can do. We see similar changes in fine motor skills with 4-year-olds who no longer struggle to put on their clothes, something they may have had problems with two years earlier. Motor skills continue to develop into middle childhood, but for those in early childhood, a play that deliberately involves these skills is emphasized. 

Children’s Art: Children’s art highlights many developmental changes. Kellogg (1969) noted that children’s drawings underwent several transformations. Starting with about 20 different types of scribbles at age 2, children move on to experimenting with the placement of scribbles on the page. By age 3 they are using the basic structure of scribbles to create shapes and are beginning to combine these shapes to create more complex images. By 4 or 5 children are creating images that are more recognizable representations of the world. These changes are a function of improvement in motor skills, perceptual development, and cognitive understanding of the world (Cote & Golbeck, 2007).

The drawing of tadpoles (see Figure: 4.4) is a pervasive feature of young children’s drawings of self and others. Tadpoles emerge in children’s drawing at about the age of 3 and have been observed in the drawings of young children around the world (Gernhardt, Rubeling & Keller, 2015), but there are cultural variations in the size, number of facial features, and emotional expressions displayed.

Gernhardt et al. found that children from Western contexts (i.e., urban areas of Germany and Sweden) and urban educated non-Western contexts (i.e., urban areas of Turkey, Costa Rica and Estonia) drew larger images, with more facial detail and more positive emotional expressions, while those from non-Western rural contexts (i.e., rural areas of Cameroon and India) depicted themselves as smaller, with less facial details and a more neutral emotional expression. The authors suggest that cultural norms of non-Western traditionally rural cultures, which emphasize the social group rather than the individual, maybe one of the factors for the smaller size of the figures compared to the larger figures from children in the Western cultures which emphasize the individual.

Table 4.1

Toilet Training

Toilet training typically occurs during the first two years of early childhood (24-36 months). Some children show interest by age 2, but others may not be ready until months later. The average age for girls to be toilet trained is 29 months and for boys, it is 31 months, and 98% of children are trained by 36 months (Boyse & Fitzgerald, 2010). The child’s age is not as important as his/her physical and emotional readiness. If it started too early, it might take longer to train a child. If a child resists being trained or is not successful after a few weeks, it is best to take a break and try again later. Most children master daytime bladder control first, typically within two to three months of consistent toilet training. However, nap and nighttime training might take months or even years.

According to the Mayo Clinic (2016b), the following questions can help parents determine if a child is ready for toilet training:

  • Does your child seem interested in the potty chair or toilet, or in wearing underwear?
  • Can your child understand and follow basic directions?
  • Does your child complain about wet or dirty diapers?
  • Does your child tell you through words, facial expressions or posture when he or she needs to go?
  • Does your child stay dry for periods of two hours or longer during the day?
  • Can your child pull down his or her pants and pull them up again?
  • Can your child sit on and rise from a potty chair? (p. 1)

Some children experience elimination disorders that may require intervention by the child’s pediatrician or a trained mental health practitioner. Elimination disorders include enuresis, or the repeated voiding of urine into bed or clothes (involuntary or intentional) and encopresis, the repeated passage of feces into inappropriate places (involuntary or intentional) (American Psychiatric Association, 2013). The prevalence of enuresis is 5%-10% for 5-year-olds, 3%-5% for 10-year-olds and approximately 1% for those 15 years of age or older. Around 1% of 5-year- olds have encopresis, and it is more common in males than females. 


During early childhood, there is a wide variation in the number of hours of sleep recommended per day. For example, two-year-olds may still need 15-16 hours per day, while a six-year-old may only need 7-8 hours. The National Sleep Foundation’s 2015 recommendations based on age are listed in Figure 4.6.

Figure 4.6

Sexual Development in Early Childhood

Historically, children have been thought of as innocent or incapable of sexual arousal (Aries, 1962). Yet, the physical dimension of sexual arousal is present from birth. However, to associate the elements of seduction, power, love, or lust that is part of the adult meanings of sexuality would be inappropriate. Sexuality begins in childhood as a response to physical states and sensation and cannot be interpreted as similar to that of adults in any way (Carroll, 2007).

Infancy: Boys and girls are capable of erections and vaginal lubrication even before birth (Martinson, 1981). Arousal can signal overall physical contentment and stimulation that accompanies feeding or warmth. Infants begin to explore their bodies and touch their genitals as soon as they have sufficient motor skills. This stimulation is for comfort or to relieve tension rather than to reach orgasm (Carroll, 2007).

Early Childhood: Self-stimulation is common in early childhood for both boys and girls. Curiosity about the body and about others’ bodies is a natural part of early childhood as well. As children grow, they are more likely to show their genitals to siblings or peers, and to take off their clothes and touch each other (Okami, Olmstead, & Abramson, 1997). Masturbation is common for both boys and girls. Boys are often shown by other boys how to masturbate, but girls tend to find out accidentally. Additionally, boys masturbate more often and touch themselves more openly than do girls (Schwartz, 1999). 

Hopefully, parents respond to this without an undue alarm and without making the child feel guilty about their bodies. Instead, messages about what is going on and the appropriate time and place for such activities help the child learn what is appropriate.

Nutritional Concerns

In addition to those in early childhood have a smaller appetite, their parents may notice a general reticence to try new foods, or a preference for certain foods often served or eaten in a particular way. Some of these changes can be traced back to the “just right” (or just-so) phenomenon that is common in early childhood. Many young children desire consistency and may be upset if there are even slight changes to their daily routines. They may like to line up their toys or other objects or place them in symmetric patterns. They may arrange the objects until they feel “just right”. Many young children have a set bedtime ritual and a strong preference for certain clothes, toys or games. All these tendencies tend to wane as children approach middle childhood, and the familiarity of such ritualistic behaviors seem to bring a sense of security and a general reduction in childhood fears and anxiety (Evans, Gray, & Leckman, 1999; Evans & Leckman, 2015).

Malnutrition due to insufficient food is not common in developed nations, like the United States, yet many children lack a balanced diet. Added sugars and solid fats contribute to 40% of daily calories for children and teens in the US. Approximately half of these empty calories come from six sources: soda, fruit drinks, dairy desserts, grain desserts, pizza, and whole milk (CDC, 2015). Caregivers need to keep in mind that they are setting up taste preferences at this age. Young children who grow accustomed to a high fat, very sweet and salty flavors may have trouble eating foods that have subtler flavors, such as fruits and vegetables. Consider the following advice (See Box 4.1) about establishing eating patterns for years to come (Rice, 1997). Notice that keeping mealtime pleasant, providing sound nutrition and not engaging in power struggles over food are the main goals: 

Tips for Establishing Healthy Eating Patterns

  • Recognize that appetite varies. Children may eat well at one meal and have no appetite at another. Rather than seeing this as a problem, it may help to realize that appetites do vary. Continue to provide good nutrition, but do not worry excessively if the child does not eat at a particular meal.
  • Keep it pleasant. This tip is designed to help caregivers create a positive atmosphere during mealtime. Mealtimes should not be the time for arguments or expressing tensions. You do not want the child to have painful memories of mealtimes together or have nervous stomachs and problems eating and digesting food due to stress.
  • No short-order chefs. While it is fine to prepare foods that children enjoy, preparing a different meal for each child or family member sets up an unrealistic expectation from others. Children probably do best when they are hungry, and a meal is ready. Limiting snacks rather than allowing children to “graze” can help create an appetite for what is being served.
  • Limit choices. If you give your young child choices, make sure that you give them one or two specific choices rather than asking “What would you like for lunch?” If given an open choice, children may change their minds or ask for something that is not available or appropriate.
  • Serve balanced meals. This tip encourages caregivers to serve balanced meals. A box of macaroni and cheese is not a balanced meal. Meals prepared at home tend to have better nutritional value than fast food or frozen dinners. Prepared foods tend to be higher in fat and sugar content, as these ingredients enhance taste and profit margin because fresh food is often costlier and less profitable. However, preparing fresh food at home is not costly. It does, however, require more activity. Preparing meals and including the children in kitchen chores can provide a fun and memorable experience.
  • Do not bribe. Bribing a child to eat vegetables by promising desert is not a good idea. The child will likely find a way to get the desert without eating the vegetables (by whining or fidgeting, perhaps, until the caregiver gives in). In addition, bribery teaches the child that some foods are better than others. Children tend to naturally enjoy a variety of foods until they are taught that some are considered less desirable than others. Most important is not to force your child to eat or fight overeating food.


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Adapted from Chapter 4 from Lifespan Development: A Psychological Perspective Second Edition by Martha Lally and Suzanne Valentine-French under the Creative Commons Attribution-Noncommercial-Share Alike 3.0 unported license.

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