In the film Memento by Christopher Nolan, reverse chronology causes the audience to view Leonard Shelby as a sympathetic victim. Viewers start to watch the film when the story has reached its end. This confusing plot puts the audience in Shelby's position. They see things from his point of view. Another thing that causes Leonard to seem like the victim is his condition, which does not let him make new memories. This makes him appear to be vulnerable. Finally, the other mysterious characters such as Natalie and Teddy make Shelby seem like the innocent victim. According to what Leonard wrote in the back of his picture, Teddy can"t be trusted. This makes the audience suspicious of him throughout the entire movie.
While watching this movie, one must pay close attention. The audience is just as confused and uneasy about what is going on as Shelby is. It is as though viewers also have the condition that Shelby has because of the reverse chronological order this movie follows. The audience, too, must have that same jolt of fear from scene to scene, the recognition that they have no clue where they are or how they got here. Viewers feel sympathy because they start to see things from Leonard's perspective. They feel they need to help him find his wife's killer and take each and every one of his little facts into consideration to try and figure out the answer.
The audience also sympathizes with Leonard because of his condition. He suffers from a rare form of amnesia, which renders him incapable of retaining memories on a short-term basis. Any bit of information he learns since his injury must be recorded or will be quickly forgotten. As a result, he must use an elaborate system of notes, photographs and even tattoos to keep everything straight. This makes his "investigation" so much more difficult. One generates sympathy for a man who wants to avenge his wife's death even if he knows he won't remember that he did it.