Final answer:
The critical age hypothesis states that there is an optimal period for acquiring certain skills such as language, and cases like Genie's support this, as she did not fully master language after missing the critical period.
Step-by-step explanation:
The critical age hypothesis suggests that there is a specific time period in human development during which the brain is optimally primed to acquire certain skills, such as language. After this period, which typically ends around puberty, learning these skills becomes significantly more challenging and may not be fully attainable. The case of Genie, a girl who was isolated and neglected until the age of 13, reflects this hypothesis. Although she developed a substantial vocabulary after being rescued, she struggled to master grammar, which suggests that her linguistic abilities were hindered by missing the critical period for language acquisition.
Another example involving language development is that of a boy found in the woods, who, similarly to Genie, was isolated from language during the critical period. This led to deficits in language acquisition that were difficult to overcome later in life.