We are concerned with the causality implicit in English verbs that name interactions, either mental or behavioral, between two persons, verbs such as like, notice (mental), and help, cheat (behavioral) in such a context as Ted-Paul. Using four different methods, we show that adult native speakers think of causality in such verbs as unequally apportioned between interactants. For behavioral (or action) verbs greater causal weight is given to the Agent argument of the verb (e.g., Ted in Ted helps Paul) than to the Patient argument (Paul). For mental (or state) verbs greater causal weight is given to the Stimulus argument of the verb (e.g., Paul in Ted likes Paul) than to the Experiencer argument (Ted). For English verbs of the type studied, derivational adjectives often exist (e.g., helpful, cheating, likable, noticeable). Such adjectives are attributive to one or the other argument of the verb base (Agent or Patient; Stimulus or Experiencer). We show that the direction of causal attribution in the adjective (e.g., helpful is attributive to Ted the Agent; likable is attributive to Paul the Stimulus) predicts the primary causal weightings assigned in our experimental tasks. We also show that in the English language adjectives derived from action verbs are almost attributive to the Agent and adjectives derived from state verbs to the Stimulus. Because certain facts about English morphology predict certain ways of thinking about causality, our main finding may seem to be a Whorfian one, a demonstration that language affects thought. However, we argue that it is not that but rather a demonstration that two modes of thought (the Agent-Patient Schema and the Stimulus-Experiencer Schema) affect language use. We suggest that the schemas are universals of human thought.