Final answer:
When the elevator scapulae muscle contracts, it causes the elevation movement of the scapula, which is the upward motion that occurs during shoulder shrugging.
Step-by-step explanation:
When the elevator scapulae muscle contracts, it lifts the scapula in a motion called elevation, which is an upward movement of the scapula and shoulder. This is similar to the motion used when shrugging your shoulders. The elevator scapulae is one of the several muscles that are responsible for controlling the movements of the scapula, along with the trapezius and other scapular muscles. Contraction of this muscle does not involve protraction or retraction; it is specifically responsible for the elevation of the scapula.