Walking around in downtown SF, I am consistently surprised by how few people are listening to iPods or other mp3 players. The percentage is maybe 5-10% on a good day.
Contrast that to what percentage of people listen to the radio or CDs while they drive their cars, which is well above 50% from my personal experience. If so many people listen to the radio in the car, it doesn't make sense that so few would listen to their mp3 players while walking around outside. I have a few hypotheses to explain this discrepancy in behavior:
1) They expect to run in to somebody and begin to talk with them, and feel that it will be awkward if they have to take off their headphones in order to have this conversation.
2) People have fewer mp3 players than I expect based on my biased college student sample. CNET reported in 2006 that 20% of people owned a portable mp3 player, however, so I would expect that by now that number would be about 30%. And in an affluent city like San Francisco, this percentage of the population ought to be even higher. This is no excuse.
3) Walkers actually prefer to listen to the hustle and bustle of the city, or to hear an occasional bird chirp. Yawn.
4) Pedestrians are worried that listening to an iPod will make them more likely to be hit by a car or otherwise put in danger (by a construction site, for example).
5) Social pressure portrays listening to an mp3 player as a negative activity. People conform to societies expectations and deny themselves the pleasure of listening to music.
Numbers 1-4 strike me as woefully inadequate, and therefore I am forced to put forth number 5 as the primary explanation. It is a sad state of affairs for modern society that people deny themselves the pleasure of music, especially since we generally rate commuting to be our least favorite activity, and music or a podcost could help mitigate our boredom. This is why, by the way, I didn't particularly like Wall-E.
The next time that you feel bad about putting your mp3 player and entering your own world in a public place, picture me giving you a big thumbs up. Love yourself for what you are, not for what society wants you to be.