Final answer:
The ghost in 'Hamlet' captures audience attention by adding suspense and intrigue, as well as infusing the play with supernatural and thematic elements that create depth and curiosity about the ghost's true nature and purpose.
Step-by-step explanation:
The introduction of the ghost in Act I of Hamlet plays a crucial role in piquing the interest of the audience. The ghost immediately introduces an element of suspense and intrigue, spurring the viewers to question its intentions and origins. This supernatural phenomenon not only adds depth and mystery to the narrative but also raises thematic questions surrounding death, afterlife, and possibly the political landscape of Elizabethan England, if one considers the historical context and belief systems of that time. The presence of the ghost shakes the foundation of the play's reality, compelling the audience to eagerly follow each development to unravel the truth behind its appearance.