This paper discusses how the argument structure of experience predicates may be affected by semantic factors in Indo-European. I investigate whether the semantic role of the experiencer is preferably expressed by the nominative or by an oblique case in various predicates of volition, cognition, propositional attitude, psychological experience and physical perception in each Indo-European branch, with particular consideration of Hittite, Old Indic, Ancient Greek, Latin, Classical Armenian and Tocharian. In my data, while the nominative coding of the experiencer tends to be generalized to heterogeneous semantic classes of experience predicates, an oblique experiencer occurs with more specific lexical categories, that is, the predicatelike/pleaseon the one hand and predicates of negative experience on the other. Interestingly, negative experiences ofbeing sad, sickorunluckyare syntactically associated with oblique experiencers much more commonly than their correspondent positive experiences ofbeing happy, healthyorlucky. This asymmetrical representation of negative and positive experiences has parallels in other language families and may have a cognitive motivation, whereby bad physical or psychological conditions are conceptualized as external forces attacking unwilling humans who have no control of them. This may be relevant not only for the currently debated issue of Indo-European argument marking, but also for an integration of semantic and cognitive principles into historical linguistics.