First, I find that most people (including myself) talk louder on the phone or headset than to an adjacent person. I attribute it to a combination of lousy acou

First, I find that most people (including myself) talk louder on the phone or headset than to an adjacent person. I attribute it to a combination of lousy acoustics and a lack of visual cues. If you talk at the same volume, maybe you just have a better phone or headset than most people. Second, I don't think it's a matter of eavesdropping; rather, it seems harder to ignore a half-conversation than a full one, because the latter is normal and expected. Maybe we will eventually become habituated, and in another 10 years we will all be walking around talking to our glasses, watches, or whatever, automatically ignoring each other.