Surrogates' decisions to withhold or withdraw life-sustaining treatments (LSTs) are pervasive. However, the factors influencing surrogates' decisions to initiate LSTs are relatively unknown. We present evidence from two experiments indicating that some surrogates' decisions about when to initiate LSTs can be predictably manipulated. Factors that influence surrogate decisions about LSTs include the patient's cognitive state, the patient's age, the percentage of doctors not recommending the initiation of LSTs, the percentage of patients in similar situations not wanting LSTs, and default treatment settings. These results suggest that some people may use heuristics when making these important life-and-death decisions. These findings may have important moral implications for improving surrogate decisions about LSTs and reconsidering paternalism.