Which defense mechanism involves taking out "pent-up" emotions on something else?

The correct response is displacement, which is a defense mechanism where an individual redirects emotions or feelings from the original source of stress or frustration onto a safer or less threatening target. This can occur when a person feels unable to express their emotions directly to the source due to fear of consequences or social norms. For example, if someone feels anger towards their boss but cannot express that anger at work, they might come home and take out their frustration on family members or pets. This redirection helps the individual cope with feelings they cannot express openly, albeit in an unhealthy way.

Rationalization involves justifying behaviors or feelings with logical reasons, often to avoid confronting the real reasons behind them. Regression refers to reverting to behaviors characteristic of an earlier developmental stage during times of stress. Projection involves attributing one's own unacceptable feelings or thoughts to others. None of these mechanisms involve the specific action of redirecting emotions onto other targets, which is the defining characteristic of displacement.