It has changed the dynamic of turning social activities in to solo activities. This is disconnecting families and societies. Music, TV, and even videogames used to be something a family or friends would share interest in. Now it is blasted in to the eardrums of one person, blocking out the world around them and shutting them in to little bubbles.
Headphones themselves are not as bad as earbuds. Earbuds are being turned up to extreme volumes because people want to block out the world around them. Headphones do this with out the super high damaging volumes because headphones are circles with foam or rubber connected by a headband like piece. This actually turns them into noise canceling, not just over powering the sounds around someone.
This article broke down the history and the damage that is caused by headphones and earbuds alike. They were created of course for something far different than for what they are used for today. There is tons of information out their on the damaging affects headphones have on hearing