There are numerous critical periods throughout the maturation of a human. For example, there are developmental periods during which language is most readily learned, physical sensations are developed, emotional responses are mastered, and movement is refined. The enhanced neuroplasticity that allows for these critical periods doesn’t last forever, so once a period is passed it’s especially difficult to learn a new skill. This hypothesis posits that psychedelics may temporarily reinstate this plasticity, sensitizing adults to environmental inputs and facilitating the relearning process that can be optimized via psychotherapy.