16 Unit 1 Children and Families in Today’s World Copyright Goodheart-Willcox Co., Inc. In a positive way, the principle suggests devel- opment does not reverse overnight. A few mistakes or stresses usually do not cause severe problems. As an example, a one-day junk food binge does not seriously harm a healthy person. The principle is also positive in that setbacks in development can be overcome with correct intervention and effort. On the negative side, the principle can work to a person’s disadvantage. It suggests that poor growth and development are not easily reversed. Consider a child with poor health due to a life- long poor diet. It may take many months or years of eating a carefully planned diet to restore the child’s health. In some cases, the body may never be able to overcome these obstacles. Consider, too, a child who lags in intellectual development due to the lack of quality experiences with adults and with toys and books. Once extremely behind in learning, it is diffi cult to overcome the learning gap between where the child is and where he or she should be. Growth and Development Happen in Sequenced Steps For growth and development to be continu- ous, change must build on what children have already learned. For instance, writing comes from making random marks. The steps in growth and development follow one another in a set order called sequenced steps. These sequenced steps are called stages or milestones. Research- ers have codified (arranged in an orderly way) the milestones through many years of obser- vations. The sequence should always lead to greater complexity of behaviors, such as scoot- ing to skipping, thinking in prelogical to logical terms, and watching others play to interacting in team sports. How do milestones aid those who are work- ing with children? Milestones give adults ideas about teachable moments. A teachable moment is an optimal time when a person can learn a new task. Teachable moments occur when the body and mind are physically ready, when caregiv- ers encourage and support the child, and when the child feels a strong desire to learn. If a child has not reached the teachable moment, he or she will feel stressed when trying to master a task or skill. Waiting too long after the teachable moment occurs may cause problems, too. For example, a child who is ready to ride a bicycle is not given the chance to learn. This child may then have trouble learning the skill as an adult. Growth and Development Happen at Different Rates Growth and development happen at differ- ent rates for different people. All people change with time. Some people enter a stage earlier and some later than the typical age. Researchers know the typical time when a developmental milestone occurs. The timing is called an age norm and can be expressed as an average age or age range. The age norm simply predicts when development will likely occur. Developmental acceleration occurs when a child performs like an older child. For exam- ple, a 30-month-old child who speaks in long, Figure 1.7 Children must practice many motor skills before they take their fi rst steps. What are some of these motor skills?