Walkman effect
n. The disengagement from surrounding public space caused by the use of technology, such as a portable music player.
In the years since Hosokawa described the Walkman effect, unspoken rules for using headphones in public spaces have developed and are largely respected. Often this simply means knowing when and where to remove them.
—Anisse Gross, “What's the problem with Google Glass,” The New Yorker, March 04, 2014
What does seem certain is that online shopping will intensify the "Walkman effect," which invites people to leave public spaces and retreat into private ones created by technological change. Like listening to a CD through a set of earphones, shopping on the Web is a solitary act.
—Jonathan Yardley, “Sold on the Web,” The Washington Post, December 06, 1999
1984 (earliest)
walkman. Thus, with the appearance of this novel gadget, all passers-by are inevitably involved in the walkman-theatre, as either actors (holders) or spectators (beholders): ’There is no difference which separates passivity and activity, but only that which distinguishes the different ways of socially marking the space effected in a given (un donné) by a practice’ (de Certeau 1980A, p. 248).

The walkman effect must be measured in terms of this practical mode of operation.
—Shuhei Hosokawa, “The Walkman Effect,” Popular Music, January 01, 1984