Which statement correctly distinguishes a critical period from a sensitive period?

• A. Critical period is a time window during which a specific experience is necessary for typical development; the sensitive period is a time when experiences have greater impact but are not strictly required.
• B. A critical period lasts longer than a sensitive period and both require identical experiences.
• C. Critical periods apply only to language learning in humans.
• D. Sensitive periods are the only times when development can occur.

Answer: (A)

Understanding how timing of experiences shapes development is key here. A critical period is a specific, narrow window during which a particular experience is necessary for typical development; if that experience is missing or abnormal during that time, certain abilities may fail to develop properly and later remediation is limited. The best way to see this distinction is to recognize that there’s a built-in requirement during that window.

A is correct because it captures this necessity-for-a-typical-outcome idea for critical periods, while also describing sensitive periods as times when experiences have greater impact but aren’t strictly required. In a sensitive period, the system is especially responsive to input, so learning or development can proceed more easily then, but it can still occur outside that window, just less efficiently or with more effort.

For context, many domains show these differences. For example, certain visual-development experiences are essential during early life; deprivation can cause lasting deficits, illustrating a critical period. Language learning, by contrast, tends to be more flexible: it’s easier during early years, but new language learning is still possible later, reflecting a sensitive period.

The other options aren’t accurate: the second suggests the periods are the same length and require identical experiences, which misstates the distinctiveness and timing. The third limits critical periods to language in humans, which isn’t true across species and domains. The fourth implies development only occurs during sensitive periods, which ignores the possibility of development during non-sensitive times.