Final Answer:
The cognitive changes commonly found in adolescence include A. improvement in the ability to think abstractly and C. increase in reflective thought.
Step-by-step explanation:
During adolescence, individuals typically experience cognitive development that involves enhanced abstract thinking (Option A). This means they can grasp more complex and hypothetical concepts, moving beyond concrete, tangible ideas. The ability to think abstractly is crucial for problem-solving and reasoning.
Additionally, adolescence is marked by an increase in reflective thought (Option C). This refers to the capacity to contemplate and evaluate one's own thoughts and experiences. Reflective thought contributes to the development of critical thinking skills and self-awareness, which are important aspects of intellectual growth during this stage.
However, it's essential to note that a decline in long-term memory (Option B) and a decrease in learning speed (Option D) are not commonly associated with adolescence.
In fact, memory capacity tends to improve during this period, and while there may be variations in learning speed among individuals, a general decrease is not a normative aspect of cognitive development in adolescence.
Therefore, the choices made, A and C, accurately reflect the cognitive changes commonly observed during this developmental stage.