While studies have demonstrated that listening to music before doing a task can improve performance on that task, chiefly through its effect on mood, there has been little research into the effects of background music while doing the task. A new study had participants recall a list of 8 consonants in a specific order in the presence of five sound environments: quiet, liked music, disliked music, changing-state (a sequence of random digits such as "4, 7, 1, 6") and steady-state ("3, 3, 3"). The most accurate recall occurred when participants performed the task in the quieter, steady-state environments. The level of recall was similar for the changing-state and music backgrounds.

Mind you, this task (recall of random items in order) is probably particularly sensitive to the distracting effects of this sort of acoustical variation in the environment. Different tasks are likely to be differentially affected by background music, and I’d also suggest that the familiarity of the music, and possibly its predictability, also influence its impact. Personally, I am very aware of the effect of music on my concentration, and vary the music, or don’t play at all, depending on what I’m doing and my state of mind. I hope we’ll see more research into these variables.