The Effects of Different Interaction Protocols statistical in nature and are generally limited to the few adults (and sometimes children) in the household. Adapting these two groups of larger sizes and variation is difficult. In the context of agent-based systems, agents interact with each other using interaction proto- cols. These are mostly used for open systems and in simulations looking for an optimal strategy, such as auction strategies. For our context, we are seeking a method for modelling the decision processes of individuals in a realistic manner in order to see the effects on the overall environment, not to recommend strategies. In this project, we are interested in the influence of the interaction protocol and decision making on the number, frequency and type of social activi- ties generated and scheduled. As incorporating detailed interactions into agent-based models of activity-travel behaviour will add a lot of com- plexity and require more intensive data collections freight handling and routing. Larger scale frame- works, such as MATSIM (http://matsim.org), can incorporate activity scheduling along with travel modelling and therefore have the ability to model activity choice in more detail. 2.1. Activity-Travel Modelling Human activities are generated due to "physiologi- cal, psychological and economical needs" (Wen & Koppelman, 2000). A distinction is commonly made between subsistence (e.g., work-related), maintenance (e.g., keeping the household run- ning), and leisure activities. Non-discretionary activities such as work and school can be partly explained by the traveller's sociodemographic characteristics and generalised travel costs (Hackney & Marchal, 2007), as well as long-term decisions such as a decision to move to a particular town. Participation in and scheduling