The ultimate goal of research in the field of agents is to mimic human conversation in such way that it could pass the so called 'Turing test' (Turing 1950). The test would not only include language transferred as text but different modalities like real audio output, the graphical representation of the conversational partner and its non-verbal behaviours. To accomplish this final goal it is necessary to understand how and why humans employ different modalities to effectively communicate. In the next section we will analyse human interaction and present two psychological models of interaction. We also relate this work back to Virtual Reality interfaces by casting a short look on the theoretical concept of presence in the end.
2.5.1. Conversational Models
2.5.2. Cognitive Ergonomics
2.5.3. Ecological Psychology
2.5.4. The concept of presence