Modernist literature often concentrates on a “personal relationship with the past”. The overwhelming subtext of As I Lay Dying deals directly with this concept, focusing thematically and stylistically on the subjectivity of experience.
Taking a look at the novel on a stylistic level, we see that the prose of As I Lay Dying is impressionistic and expressive of individual psychological filtering, emphasizing the subjectivity of perception.
The notion that different people see the world differently, though they are looking at the same things in the same world, is a trend in modernist literature (though it is not a rule).
In this novel, each character is given his or her own way of seeing, rendering the world of the novel as a prosaic, subjective experience. It is this individualized and impressionistic perspective that is perhaps the most clearly "modernist" element of As I Lay Dying.