The Preschool Years

Published on 22/03/2015 by admin

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Chapter 10 The Preschool Years

The critical milestones for children ages 2 to 5 yr are the emergence of language and exposure of children to an expanding social sphere. As toddlers, children learn to walk away and come back to the secure adult or parent. As preschoolers, they explore emotional separation, alternating between stubborn opposition and cheerful compliance, between bold exploration and clinging dependence. Increasing time spent in classrooms and playgrounds challenges a child’s ability to adapt to new rules and relationships. Preschool children know that they can do more than ever before, but they also are increasingly cognizant of the constraints imposed on them by the adult world and their own limited abilities.

Physical Development

Somatic and brain growth slows by the end of the 2nd yr of life, with corresponding decreases in nutritional requirements and appetite, and the emergence of “picky” eating habits (see Table 13-1). Increases of ~2 kg (4-5 lb) in weight and 7-8 cm (2-3 in) in height per yr are expected. Birthweight quadruples by image yr of age. An average 4 yr old weighs 40 lb and is 40 in tall. The head will grow only an additional 5 cm between ages 3 and 18 yr. Current growth charts, with growth parameters, can be found on the Centers for Disease Control and Prevention website (www.cdc.gov/nchs) and in Chapter 13. Children with early adiposity rebound (increase in body mass index) are at increased risk for adult obesity.

Growth of sexual organs is commensurate with somatic growth. The preschooler has genu valgum (knock-knees) and mild pes planus (flatfoot). The torso slims as the legs lengthen. Physical energy peaks, and the need for sleep declines to 11-13 hr/24 hr, with the child eventually dropping the nap (see Fig. 8-1). Visual acuity reaches 20/30 by age 3 yr and 20/20 by age 4 yr. All 20 primary teeth have erupted by 3 yr of age (Chapter 299).

Most children walk with a mature gait and run steadily before the end of their 3rd yr (see Table 9-1). Beyond this basic level, there is wide variation in ability as the range of motor activities expands to include throwing, catching, and kicking balls; riding on bicycles; climbing on playground structures; dancing; and other complex pattern behaviors. Stylistic features of gross motor activity, such as tempo, intensity, and cautiousness, also vary significantly. Although toddlers may walk with different styles, toe walking should not persist.

The effects of such individual differences on cognitive and emotional development depend in part on the demands of the social environment. Energetic, coordinated children may thrive emotionally with parents or teachers who encourage physical activity; lower-energy, more cerebral children may thrive with adults who value quiet play.

Handedness is usually established by the 3rd yr. Frustration may result from attempts to change children’s hand preference. Variations in fine motor development reflect both individual proclivities and different opportunities for learning. Children who are seldom allowed to use crayons, for example, develop a mature pencil grasp later.

Bowel and bladder control emerge during this period, with “readiness” for toileting having large individual and cultural variation. Girls tend to train faster and earlier than boys. Bed-wetting is normal up to age 4 yr in girls and age 5 yr in boys (Chapter 21.3). Many children master toileting with ease, particularly once they are able to verbalize their bodily needs. For others, toilet training can involve a protracted power struggle. Refusal to defecate in the toilet or potty is relatively common and can lead to constipation and parental frustration. Defusing the issue with a temporary cessation of training (and a return to diapers) often allows toilet mastery to proceed.

Language, Cognition, and Play

These three domains all involve symbolic function, a mode of dealing with the world that emerges during the preschool period.

Language

Language development occurs most rapidly between 2 and 5 yr of age. Vocabulary increases from 50-100 words to more than 2,000. Sentence structure advances from telegraphic phrases (“Baby cry”) to sentences incorporating all of the major grammatical components. As a rule of thumb, between the ages of 2 and 5 yr, the number of words in a typical sentence equals the child’s age (2 by age 2 yr, 3 by age 3 yr, and so on). By 21 mo to 2 yr, most children are using possessives (“My ball”), progressives (the “-ing” construction, as in “I playing”), questions, and negatives. By age 4 yr, most children can count to 4 and use the past tense; by age 5 yr, they can use the future tense. Children do not use figurative speech; they will only comprehend the literal meaning of words. Referring to an object as “light as a feather” may produce a quizzical look on a child.

It is important to distinguish between speech (the production of intelligible sounds) and language, which refers to the underlying mental act. Language includes both expressive and receptive functions. Receptive language (understanding) varies less in its rate of acquisition than does expressive language; therefore, it has greater prognostic importance (Chapters 14 and 32).

Language acquisition depends critically on environmental input. Key determinants include the amount and variety of speech directed toward children and the frequency with which adults ask questions and encourage verbalization. Children raised in poverty typically perform lower on measures of language development compared to children from economically advantaged families.

Although experience influences the rate of language development, many linguists believe that the basic mechanism for language learning is “hard-wired” in the brain. Children do not simply imitate adult speech; they abstract the complex rules of grammar from the ambient language, generating implicit hypotheses. Evidence for the existence of such implicit rules comes from analysis of grammatical errors, such as the overgeneralized use of “-s” to signify the plural and “-ed” to signify the past (“We seed lots of mouses.”).

Language is linked to both cognitive and emotional development. Language delays may be the first indication that a child has mental retardation, has an autism spectrum disorder, or has been maltreated. Language plays a critical part in the regulation of behavior through internalized “private speech” in which a child repeats adult prohibitions, first audibly and then mentally. Language also allows children to express feelings, such as anger or frustration, without acting them out; consequently, language-delayed children show higher rates of tantrums and other externalizing behaviors.

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