PNU Professional Education Practice Test

Development is the process by which a person’s abilities and behaviors become more complex and functional over time, moving from simple, automatic responses to purposeful actions that reflect growing interaction with people and the environment. A baby smiling at a sound captures this shift most clearly: it isn’t just a direct reaction to a stimulus, but a purposeful social-emotional response that shows the infant is coordinating perception (the sound) with a social signal (a smile). This kind of early social responsiveness marks a foundational developmental milestone.

The other scenarios describe learning a specific skill or physical growth rather than a change in overall functioning: operating a computer is acquiring a task, growing taller is physical growth, and learning to read is a later cognitive skill.