In this paper we describe our research on how to design for perceptive activity in artifacts in order for perceptual crossing between subject and artifact to happen. We base our research on the phenomenology of perception [19] and on ecological psychology [10]. Perceptual crossing is believed to be essential to share perception and thereby to feel involved in the situation [5, 15]. We propose a theoretical model in which perceptive connections between user, artifact and event are presented. We designed an artifact to function as physical hypotheses [9] and show the design relevance of the model. In an experiment we investigate how the user’s feeling of involvement is influenced in relation to differentiations of the proposed theoretical model. The results of our experiment show that indeed perceptual crossing between user and artifact influences the user’s feeling of involvement with the artifact in their common space. We conclude with describing several design notions important for designing for perceptive activity in artifacts.