Answer:
Allen tells his roommate that he thinks that smoking marijuana is wrong. A few weeks later, Allen tries smoking marijuana. Allen soon feels uncomfortable because his behavior was inconsistent with his attitude, so he decides that smoking marijuana must not be so wrong after all. Allen's change of belief can best be explained by cognitive dissonance theory.
Explanation:
The cognitive dissonance theory explains the tension a person feels when they beliefs are in conflict with their behaviours, a person says and belifefs something (in this case, Allen believes smoking marijuana is wrong), but then acts inconsistent with their beliefs (in this case, Allen then smokes marijuana).
