HCI implications of a colored petri net model for gibson's affordance

In this paper, a formal model of affordances using a Colored Petri Net is proposed. The concept of affordance has existed for over three decades, but no consensus has been reached on its interpretation and modeling. Gibson first proposed a definition of an affordance as, "what the environment offers an animal for good or ill". Since then, different communities have provided assorted interpretations for affordance theory. While some ecological psychologists believe that an affordance is a dispositional property of the environment that have consequences for the animal's behavior, others argue that an affordance is a higher order property of the animal environment system that refers to a mutual relation between the animal and its environment. The notion of an affordance has had a great intuitive appeal in HCI. We seek to build upon existing work to formalize this notion so that it can be used to improve our understanding of an activity which is situated in a dynamic world. We begin by characterizing an affordance as having the properties of concurrency, stochasticity and spatio-temporality. We then demonstrate the sufficiency of a Colored Petri Net (CPN) model for modeling an affordance by encompassing all the stated properties. The CPN model is proposed within the context of highway driving scenario but could be extended to analyze other HCI domains.