What is the psychophysical reason behind facial contortions during guitar playing?

I%26#039;d really like to know if anyone has any type of scientific theory about why many guitar players contort their faces while they play.|||I%26#039;ve noticed that too, and have thought it interesting.





I think there are several things going on, actually.





One is concentration, as noted by the other answerer. People often have odd expressions when they are doing something difficult or intense - think of the action shots of pro basketball players as they are driving to the hoop.





A second component is showmanship. I would guess at least some of the expressions of John Mayer are theatrical embellishments.





But I also think there is also some level of unconscious neural involvement that isn%26#039;t just the effect of concentration.





What I have noticed is that a lot of times the guitarists are mouthing the notes as they are playing. So my hypothesis is that the action of playing a guitar is somehow involving the areas of the brain that are involved in oral communication - areas that affect things like rhythm, cadence, and audio structure. We usually employ these areas when we talk, and so I guess that as a player is exerting her/himself to play a solo that sounds rhythmic and melodic and in sync with the rest of the song, s/he is unconsciously manipulating her or his face - and maybe even vocal cords - as though they were somehow speaking the notes from the guitar.





I think that makes sense, but I don%26#039;t know of any studies that have linked involvement of the speech centers of the brain to the production of music.|||It%26#039;s a concentration thing, that%26#039;s all.