Natasha's hot pink headphones symbolize her desire to shut herself out from the rest of the world. Although the headphones were a gift from Samuel and therefore a demonstration of his love and affection, Natasha views them as a tool to isolate herself and ignore the novel's overwhelming assertion that all beings are somehow connected to each other. It's telling, then, that Natasha allows herself to connect with Daniel after her headphones break—their absence means that she can no longer ignore that she does indeed have ties to others.
Headphones Quotes in The Sun is Also a Star
She glances up at me again but shows no sign that she recognizes me, even though I've been here every day for the last week. To her I'm just another anonymous face, another applicant, another someone who wants something from America.