Final answer:
Yes, skills and knowledge can be learned after a sensitive period has passed, though it may be harder. Examples such as Genie's language acquisition and the concept of latent learning illustrate this possibility. Education, critical for human capital deepening, may have diminishing returns but is still valuable.
Step-by-step explanation:
Skills and knowledge can indeed be learned at a later time after a sensitive period has passed, albeit potentially with more difficulty or to a lesser extent. A sensitive period is a timeframe in an individual's development when they are more receptive to certain types of learning. Outside of this period, while learning can still occur, it may not be as natural or easy. For example, the case of Genie illustrates that after being removed from an abusive environment, she could acquire a significant vocabulary well beyond the typically defined critical period for language acquisition. However, certain aspects of language, such as grammar, proved to be more elusive for Genie—suggesting that while learning can occur after sensitive periods, there might be varying degrees of success based on the skill or knowledge area.
Latent learning is another concept demonstrating that learning can happen without immediate signs. As in the case of Ravi, who learned the route to school without the need for immediate application, and applied it successfully when required. This shows that humans are capable of acquiring skills and knowledge that may not even be evident until a later time when needed.
Finally, in the broader context of human capital deepening, while continuous education and knowledge acquisition are beneficial and contribute to personal and economic growth, there may be diminishing returns at certain points. However, the pursuit of lifelong learning remains crucial for adaptation and innovation.