Alexis has just seen a play in which Olivia portrayed the villain. Olivia's performance was brilliant and quite convincing. Despite knowing that Olivia was just acting, Alexis insists that Olivia must have a mean, devious, and villainous side to her personality. This belief is being influenced by:

The fundamental attribution error

Explanation:

When a person believes that the cause of behavior of another person is the due to the internal factors of the other person. The external factors are not taken into account. This phenomenon is known as the fundamental attribution error.

Here, Alexis thinks that Olivia portrayal of a villain was good due to fact that she was inherently evil. Alexis did not take into account Olivia's training, practice she had done for her performance which are external factors.