Final answer:
The metaphor used in Brent Staples' essay highlights the paradoxical need for Staples to signal his non-threatening nature through whistling, similar to how hikers use cowbells to alert bears to their presence, emphasizing the negative consequences of racial stereotypes.
Step-by-step explanation:
The last sentence of paragraph 12 in Brent Staples' essay uses a powerful metaphor to express the complication and paradox of Staples' attempts to put others at ease due to racial stereotypes. By comparing his whistling of classical music to a cowbell worn by hikers in bear country, Staples underscores a sobering reality: the music serves as a tool to signal his harmlessness, much like the cowbell signals a hiker's presence to prevent startling a bear. This metaphor articulates the negative consequences of Staples' interactions with others; it suggests that, like hikers who must take precautions against bears, Staples must manage the perceptions of those around him due to preconceived notions based on his race.