Identify the type of body movement

placing an index finger on lips to request silence

regulator

illustrator

emblem

adaptor

affect display

The type of body movement in placing an index finger on lips to request silence is that of an emblem.

Explanation:

The action of trying to convey to stop another action in progress can be referred to as an 'emblem'. When an action is controlled by posing a counter-action that has a conventionally accepted meaning, the action that is performed to 'control' can be called as the 'emblem' action owing to the meaning pre-assigned to it.