Name this phenomenon: You're shy of doing X because nobody else around you does it I'm looking for the name of the following phenomenon.

Image this situation:

A teenager is riding a bus. He's thirsty. He has a water bottle in his bag, but he doesn't feel comfortable bringing it out and drinking because "I'll look dumb". (Let's assume nobody else in the bus is drinking.)

(I'd also like to know: (1) Are teenagers more susceptible to this?
(2) Does it have to do with self-esteem?)
I think the term you are looking for is social norm, peer norm, or social expectation.

Distinguish from peer pressure, which is a different phenomena, yet related.

Many researchers have shown that teens are more susceptible to peer pressure (which implies the same for peer norms).

Both relate to self-esteem, and while mostly mentioned as facilitators, there is research out there to show that people with low self-esteem are more susceptible to both.

See, for example:


Sumter, S.R., Bokhorst, C.L., Steinberg, L. and Westenberg, P.M., 2009. The developmental pattern of resistance to peer influence in adolescence: Will the teenager ever be able to resist?. Journal of adolescence, 32(4), pp.1009-1021.
Zimmerman, M.A., Copeland, L.A., Shope, J.T. and Dielman, T.E., 1997. A longitudinal study of self-esteem: Implications for adolescent development. Journal of youth and Adolescence, 26(2), pp.117-141.