The Multi-Source Interference Task (MSIT) was developed to examine the neural networks associated with attention and cognitive interference. The MSIT combines different types of interference known to delay reaction time for the purpose of maximizing cognitive interference. The MSIT has been shown to produce activation in the anterior cingulate cortex, a region of the brain implicated in processes of executive attention. Previous work has not addressed the separate influences of each source of interference. This study was designed to decompose the sources of interference to determine their independent contributions. Participants were instructed to identify the number that was different in a three digit array. Font cue, flanker, and spatial interference factors were evaluated. Additionally, blocked versus mixed design was compared. It was found that trials with one type of interference were easier to resolve than trials with two types of interference. Further, the presence of a target font cue diminished interference. Blocking was also found to yield faster response, but only in trials with minimal interference. Finally, trials with congruent types of interference were more difficult than trials with incongruent interference. Results of the study can be used to design a maximally potent MSIT.