In this section, an overview of the field of Pedagogic Conversational Agents (PCAs) is presented to introduce the basic necessary context for anyone who wants to create new agents. It is out of the scope of this paper to accomplish a complete review of the state-of-the-art of the field.
Appearance
The appearance of the agent is a key issue in the design of a PCA. There are studies indicating that a human form for the agent provides advantages to the student-system interaction (Lester et al., 1997; Cassell & Tartaro, 2007). Figure 1 shows a sample of agent with human appearance.
However, it should be noted that it may not be true for all cases. In particular, some researchers have warned that creating agents that look like perfect humans creates the expectation that it is possible to keep a perfect dialogue with the agent (Norman, 1994; King & Ohya, 1996; Koda & Maes, 1996).
In general, the choice of the appearance of the agent should be dependent on the nature of the task (Mencia, 2011) and the personal features and skills of the users (Xiao, 2006). Figure 2 shows some samples of agents represented by animals, when their goal is just to provide support to the students, so that they do not feel alone when working with the computer (Chen, Liao, Chien & Chan, 2009), and Figure 3 shows agents represented by little children as animated characters who seek the help of the students because they do not know how to complete the homework (Biswas et al., 2009).
Figure 2. Sample agent with animal appearance (Source: Chen et al., 2009)
Figure 3. Sample agents represented by animated characters (Source: Biswas et al., 2009)