Final answer:
The scenario given portrays the Fundamental Attribution Error, where an individual's behavior is incorrectly attributed to their character without considering external circumstances.
Step-by-step explanation:
The behavior where your new roommate leaves dirty laundry all over her room, and you assume she is a slob without considering her current situation of taking finals and working 40 hours per week is known as the Fundamental Attribution Error. This error occurs when you overestimate the extent to which a person's behavior is due to internal, dispositional factors and underestimate the role of situational factors. The actor-observer bias, self-serving bias, and just-world hypothesis are other related concepts that explain how individuals attribute causes to actions and events.