Some actions of agents are ambiguous in terms of goal-directedness to young infants. If given reasons why an agent performed these ambiguous actions, would infants then be able to perceive the actions as goal-directed? Prior results show that infants younger than 12 months can not encode the relationship between a human agent’s looking behavior and the target of her gaze as goal-directed. In the present experiments, 8-month-olds responded in ways suggesting that they interpreted an agent’s action of looking at object-A as opposed to object-B as evidence for her goal directed toward object-A, if her looking action was rational given certain situational constraints: a barrier separated her from the objects or her hands were occupied. Therefore, the infants seem to consider situational constraints when attributing goals to agents’ otherwise ambiguous actions; they seem to realize that within such constraints, these actions are efficient ways for agents to achieve goals.