The author uses these delusions as a front, showing us that the Lomans are unable to accept reality, when subconsciously we can see that Biff is different from the rest of the family. Although he is just as guilty as anyone else for the situation that they are in, he knows something more. It is not until later in the novel that Miller exposes us to what that something truly is, leaving us to ponder the broken dreams of this family for the time being.
However, as time goes on, we begin to become more and more aware that Biff is not as comfortable accepting the lie as the rest of the family has become. Miller gradually exposes us to a series of events which lead up to Biff's emotional shift following High School. By showing us the high-point in Biff's life and how it so quickly crashes into a state of self despair, Miller embodies the fact that Biff is not as accepting of the ideals that Willy tries to force down the throats of his family. All of these "flash-backs- that are experienced through the work are simply "mental- events to begin with. They are not occurring at the time in place, however, they are occurring at a time years ago. Told separately, these memories would still be important, however, by interlacing the developing plot, with the previously occurred events, Miller makes these memories twice as suspenseful and twice as climactic as they ever could have been standing alone. These mental flashbacks are the first example of how Miller succeeds in making the mental and psychological portions of the novel as poignant and strong as they end up being. However, it is not the biggest example, by any means.
Throughout the entire novel, we begin to see that Biff is not the same as the rest of his family. Likewise, by showing us the chain of events that Miller does, we can see why it is that Biff is different. Beyond the range of our coherent thought, we begin to anticipate the moment when Biff either stands up, and embraces reality, or continues to falter in the dream world Willy clings to with such dedication.