The kinds of entities that can be described as causing an event depend, in part, on the language one speaks. Whereas in English and Chinese it is possible to say The knife cut the bread or The key opened the door, in Korean and many other languages, such sentences sound very odd. According to the initiator hypothesis, languages fall into two major groups with respect to possible external arguments in causal expressions: those that require that the causer be capable of generating its own energy and those that require only that the causer participate in the causal chain leading up to a particular result. In support of this hypothesis, we show that ability to self-energize has a larger impact on acceptability ratings in Korean than in either English or Chinese (Exp. 1). We also show that restrictions on possible causers extend to the semantics of possible causes in the descriptions of animations depicting causal chains (Exp. 2). Finally, we show that cross-linguistic differences in the linguistic coding of causers may have consequences for the way people conceptualize animations of causal chains in terms of number of events (Exp. 3). Implications for the representation of verb meaning and the semantics of external arguments in other languages are discussed.

The notion of internalization put forth by Roger Shepard continues to be appealing and challenging. He suggests that we have internalized, during our evolutionary development, environmental regularities, or constraints. Internalization solves one of the hardest problems of perceptual psychology: the underspecification problem. That is the problem of how well-defined perceptual experience is generated from the often ambiguous and incomplete sensory stimulation. Yet, the notion of internalization creates new problems that may outweigh the solution of the underspecification problem. To support this claim, I first examine the concept of internalization, breaking it down into several distinct interpretations. These range from well-resolved dynamic regularities to ill-resolved statistical regularities. As a function of the interpretation the researcher selects, an empirical test of the internalization hypothesis may be straightforward or it may become virtually impossible. I then attempt to cover the range of interpretations by drawing on examples from different domains of visual event perception. Unfortunately, the experimental tests regarding most candidate regularities, such as gravitational acceleration, fail to support the concept of internalization. This suggests that narrow interpretations of the concept should be given up in favor of more abstract interpretations. However, the latter are not easily amenable to empirical testing. There is nonetheless a way to test these abstract interpretations by contrasting internalization with the opposite concept: externalization of body dynamics. I summarize evidence for such a projection of body constraints onto external objects. Based on the combined evidence of well-resolved and ill- resolved regularities, the value of the notion of internalization has to be reassessed.