nasolabial furrow deepener vs. upper lip raiser
The following videos showcase two specific facial actions in three contexts.
Part I features an action known as nasolabial furrow deepener, and Part II features an action known as upper lip raiser. Both actions pull the top lip upwards but do so in distinctly different manners. (NOTE: There are layers of other actions present in these videos as well.)
Because of its name, upper lip raiser is considered the go-to action for lifting the top lip and tends to get overused in art and tech, acting as a replacement for nasolabial furrow deepener or a shortcut for showing teeth during smiling.
Despite its name, upper lip raiser is not the only lip-raising action! In fact, applying upper lip raiser to contexts better suited for nasolabial furrow deepener can be detrimental to the essence of a target expression.
Observe how the three contexts with nasolabial furrow deepener completely change in mood when replaced with upper lip raiser especially for the empathetic/sad-like expression (the second).
For further reading on the overuse of upper lip raiser in art and tech: Building Smiles the Right Way.