Passage Summary: Back in the day, people had to imagine what radio characters looked like, but now we just watch them on TV. Because of this, the author thinks we aren't using our imaginations as much as our grandparents did.

Conclusion: Modern television viewers exercise their imaginations less frequently than previous generations who primarily listened to radio dramas.

Reasoning: Radio drama necessitates that listeners mentally visualize characters and settings, whereas television provides these visual elements directly.

Analysis: The historian is making a leap from a specific type of imaginative exercise—picturing scenes—to the frequency of imagination in general. To make this argument stick, we have to assume that television doesn't offer some other, different way to exercise the imagination that radio lacked. It's a bit like saying people are less fit today because they don't chop wood, while ignoring the fact that they might be going to the gym instead. Look for an answer that addresses whether TV viewers are getting their imaginative 'cardio' from some other source.