A challenge for psycholinguistics is to describe how linguistic cues influence the construction of the mental representation resulting from the comprehension of a text. In this paper, we will focus on one of these linguistic devices: the sentence-initial positioning of spatial adverbials such as "In the park".... Three self-paced reading experiments were conducted to test the "Discourse Framing Hypothesis" according to which preposed adverbials can be seen as frame builders announcing that incoming contents satisfy the same informational criterion specified by the adverbial. Our results indicate that spatial adverbials do not play the same role when they are in sentence-initial and in sentence-final position. These results are discussed in the framework of Zwaan's Event Indexing Model.