Personality Model of a Social Character

Virtual characters are increasingly becoming a common interface for communication between humans and computers, or for portraying human’s behaviour in leisure or educational setting (Louchart, Aylett, Pickering, Romano, 2004). If their creation aim is to portray humans, they should be inspired by the way humans express their feeling and interact with each other. We present here a personality model that attempts to emphasise the believability of a virtual character, by displaying personality and emotions in a social context. Such model enables the creation of characters that can account for both stability and variability of a real person in action and his/her behaviour across time and place. It models not only the person’s emotional status, but also the social tasks they are confronted with and construct over time, maintaining a history of the social interactions the character has held with other agents or real people in the virtual world. To meet the above requirements, elements from established personality models have been put together to form a framework of components that interacts in a consistent way to represent the personality of the character. Architecture Overview The proposed personality model consists of four modules described below. The Emotion Module defines the emotional status of a character at a particular time. Such emotional status depends not only on the current contact between the two characters but also on their interaction history. The Memory Module stores the history of previous verbal and non-verbal interactions of the character with other characters in the virtual world in the form of emotional status. The Social-Cognitive Factors Module accounts for the relatively stable personality factors over time. These factors are connected with one to several emotional attributes of the Emotion Module. The Event Processing Module determines the gestures and actions/speech actions that a character should perform according to their emotional status. Figure 1 shows the relationships between these modules. The personality model receives a notification when an event, or external stimuli, occurs in the environment, and produces an event for the environment, which represents the behaviour of the person modelled in response to the event in input. The information passed to the personality model for the occurrence of an event (e.g. shake hands, nodding, etc) includes the intensity of the event, which is strength of the emotions involved the event, and a list of the social-cognitive(SC) personality factors that the event may have an effect on, the Social Context in which the character is in and other relevant Environment Information. To express the personality of the behaviour a list of gestures and actions/speech actions is available to the model to display the personality of the character. For each gesture different intensities are available. The personality model output is the event that occurs in the environment.