Certificate In Psychology (CPSY) Practice Exam

Examination of the ages at which children achieve motor milestones shows that:

1. practice has little effect on the ages at which babies master universal skills.

2. infants are remarkably uniform in the ages at which they become able to sit, crawl, and walk.

3. 90 percent of infants have begun walking by the time they are 12 months of age.

4. there are wide variations in the ages at which infants begin to sit, walk, and crawl.

The correct answer is: there are wide variations in the ages at which infants begin to sit, walk, and crawl.

The correct answer highlights the significant individual differences in developmental milestones among infants. While there are general trends in the sequence of motor skill development, the ages at which children reach these milestones—such as sitting, crawling, and walking—can vary widely from one child to another. Factors such as genetics, environment, and individual growth patterns can all influence when an infant achieves a particular skill. This understanding is crucial, as it reflects the diverse developmental trajectories that children can take as they grow. Within any group of infants, some may begin to walk as early as 9 months, while others may not start until 15 months or later, demonstrating the variability present in early motor development. This variability underlines the importance of recognizing that developmental milestones serve as general guidelines rather than strict timelines applicable to every child.