Which ability is MOST likely to start declining by a person's thirties?

Question

Quizplus · Accepted Answer

By a person's thirties, their cognitive abilities are still generally intact, but their ability to quickly perform complex new tasks can start to decline. This is because the brain's processing speed and flexibility begin to decrease with age. Vocabulary and knowledge of history are not necessarily declining at this stage, and there is no specific ability that universally declines during this decade.

Which Ability Is MOST Likely to Start Declining by a Person's