Causal explanations affect judgments of the need for psychological treatment

Knowing what event precipitated a client's abnormal behaviors makes the client appear more normal than if the event is not known (Meehl, 1973). Does such knowledge also influence judgments of the need for psychological treatment, and if so, does it matter whether the precipitating event was inside or outside the client's control? We presented undergraduates with cases of hypothetical clients exhibiting abnormal behaviors and manipulated whether they were also told of a precipitating event explaining those behaviors. Knowing the precipitant significantly reduced perceptions of clients' need for treatment, but only when the precipitating event was outside the client's control. These findings call into question the notion that it need always be beneficial for an outside reasoner to uncover the root cause of a client's psychological problems, particularly when the root cause is still unknown to the client. The rationality of the effect and additional implications for decision-making are discussed.