Marnie can be said to be at the forefront of pioneering a psychological thriller. Many of Hitchcock's films deal with a similar aspect, but none require the viewer to pay the amount of attention that this film calls for. It is in patience and careful observation that one can begin to see the complex problems that plague Marnie every day of her life. In this observation that re can find repeating symbols such as color and animals. It is these symbols, which fuels her deceptive lifestyle ultimately leading to her breakdown, and with that breakdown letting decades of frustration and anguish as well. .
Color, in this film, is a direct indicator of what Marnie feels at the moment of whatever is going on. Two colors stand out as prominent, these being yellow and red. At the beginning of the film, we see Marnie's bag contrasting greatly with its surroundings at the train station. Accompanying the suitcase, the pencils and paper in the combination drawer are yellow as well as Mark's sleepwear. Though these do ring important, the fact that Marnie's hair color is blonde is a major indication of what importance this color has on not only her world but the how the viewer sees her as well. As her identities change, so do her hair color, but what lies underneath the dyes is the true hair color, blonde. Typically, the color yellow is associated with signs of warning and caution and the comparison here cannot be any more fitting. The lifestyle Marnie lives is one of extreme danger and risk, usually ending in apprehension and extreme punishment. And as the viewer begins to find out why Marnie is bothered so greatly, they also realize the warning signals that Marnie might not see. It is as if subconsciously she knows she's in trouble or close to it, but cannot break out of the life she lives. Yellow is also associated with cowardly behavior, almost hinting at the idea of Marnie's reluctance to confront and accept the truth.