Final answer:
Deidre is using the defense mechanism of denial by refusing to acknowledge her drinking problem, even in the face of clear evidence such as two DUIs.
Step-by-step explanation:
Deidre is demonstrating the defense mechanism known as denial. Denial refers to the refusal to accept reality or facts, blocking external events from awareness. Despite having two DUIs, which are factual indicators of a potential drinking problem, Deidre refuses to acknowledge that she has an issue with alcohol. This is a classic example of denial where an individual fails to see the truth of the situation due to its potential to cause distress or anxiety.
Defense mechanisms such as denial are unconscious psychological strategies used by individuals to protect themselves from anxiety arising from unacceptable thoughts or feelings. Sigmund Freud first proposed the theory of defense mechanisms, and it has been elaborated upon by other psychologists over time. Denial is different from displacement, another defense mechanism, which involves shifting negative feelings or behaviors to a less threatening target.
In the context of the question, displacement would not be an accurate description of Deidre's behavior, as she is not shifting her feelings onto someone or something else; she is outright refusing to acknowledge them.