What is significant about time switching back and fourth in The Brief Wondrous Life of Oscar Wao?

Within works of fiction, flash backs (analepses) and flash forwards (or prolepses) are literary devices that an author uses to interrupt the current time in the novel and take the narrative backward or forward in time. Often, these inset stories within the larger narrative arc serve a bigger literary purpose. Introducing character and plot details at intentional moments within the larger story has bearing on how characters and themes develop.

In The Brief and...

Within works of fiction, flash backs (analepses) and flash forwards (or prolepses) are literary devices that an author uses to interrupt the current time in the novel and take the narrative backward or forward in time. Often, these inset stories within the larger narrative arc serve a bigger literary purpose. Introducing character and plot details at intentional moments within the larger story has bearing on how characters and themes develop.

In The Brief and Wondrous Life of Oscar Wao, Junot Diaz's narrative moves frequently not only from one time to another, but from one narrator to another as well. Like the Dominican culture around which the story revolves, the narrative texture is varied and colorful. In addition to mirroring the Dominican spirit, Diaz's narrative choices also serve a higher literary goal. Throughout Oscar Wao, Diaz describes the juxtaposing aspects of the Dominican-American experience. A few of the overarching themes include colonization vs. belonging, superstition vs. science, and masculinity vs. female power. 

By continually switching time periods throughout the novel, Diaz continues his examination of opposites, applying that same scrutiny on time: present vs. past. In my opinion, Diaz is using that juxtaposition to make the reader ask How different are these two things actually? Throughout the novel, we see parallels and similarities between each of Diaz's juxtaposed pairs, including present and past. Prolepsis and analepsis are just two devices Diaz uses to bring the reader's attention to the novel's central themes.