This dissertation investigates to which extent internal working models of relationships and personality characteristics of participants are transferred to computer-generated agents in a virtual social environment. For this purpose a VSE was created that was populated with several autonomous agents which interacted with each other. Participants can control one of the the agents ; one of the other agents is the spouse of the protagonist. Using this setup, a potential projection screen for the dynamics of the real-life relationship, as well (...) as for generalized internal working models was created. Chapter 1 summarizes the research question, gives an overview of the development of the VSE called "Simoland", and provides a general summary and conclusion about the dissertation. Chapters 2 - 4 each are self-contained manuscripts. Chapter 2 is a theoretical article which describes challenges and new possibilities in the implementation of psychological models into autonomous agents. Chapter 3 describes the first empirical study conducted in Simoland. This study demonstrates how intrapersonal changes in interaction behavior can be investigated in VSEs. With a sample of 236 participants I could show that both the relationship satisfaction with the real life partner, and the intimacy motive of the participant had an influence on the behavior towards the virtual spouse. Hence, it could be shown that virtual behavior indeed is connected to conditions of the real world. While the first study investigated unrestricted behavior in an open world, in Chapter 4 specific, theoretically derived scenes were created which were supposed to activate the attachment system. With a sample of 422 participants we could demonstrate interindividual differences in attachment behavior as a reaction to one of three scenes: a separation, a conflict with the virtual spouse, and a threatening situation. Both attachment anxiety and attachment avoidance significantly and meaningfully correlated with the behavior in the VSE, the physical distance between protagonist and virtual spouse, and emotional ratings. To summarize, this dissertation for the first time shows that qualities of real-life relationships, as well as internal working models of attachment, are transferred to virtual agents. Thereby new ways are opened to investigate behavior in close relationships and representations of significant others through virtual scenarios. (shrink)