Final answer:
The primary age range for changes in religiousness according to developmental studies is 14 to 20 years, aligning with adolescence.
Step-by-step explanation:
According to developmental studies, the primary age range under consideration for changes in religiousness is 14 to 20 years. This period corresponds with adolescence, a significant transitional stage characterized by cognitive development and identity exploration, including the development of religious beliefs. Adolescents often inherit religious traditions from their parents, but they also start to question and form their own beliefs, a process influenced by various rituals and life stages such as Bat Mitzvah or Bar Mitzvah in Judaism, confirmations, and marriage ceremonies. This developmental stage is marked by increased abstract thinking capabilities and the emergence of more adult cognitive structures, paving the way for the solidification or transformation of their religious views.