**3.2 Methodology**

For this experimental study, 84 children (5–8 years old) were recruited and divided into pairs to collaborate with a conversational agent embodied in a table-top social robot in order to perform a Tower of Hanoi problem-solving task (see **Figure 3**). The study was structured as follows: In the preliminary session, children were introduced to the Hanoi tower game. In the robot intervention session, they collaborated with the robot to solve the task. The interview session involved a semi-structured interview and a picture task to capture children's perceptions the robot.

We manipulated two variables of the CA: its cognitive reliability and its expressivity, which are described as follows:


#### **Figure 3.**

*Experimental setup for studying collaborative problem-solving between two children and a table-top social robot using the tower of Hanoi logic task.*

sentences. While in the neutral condition, the CA has used all the time the *n*eutral configuration and the expressive condition changed between *original, calm* and *happy* configurations. We selected two different features, pitch and speed, and empirically set those parameters during the design phase of the study [56].

In the study, we measured the task performance and group dynamics during the interaction. We also interviewed children to understand both the influence of the different behaviors and children's perception of the system.

## **3.3 Results**

We summarize here the results of the study, with a focus on the link between the mentioned ethical guidelines and the communication features employed by the social robot during interactions.

The analysis of the recorded interviews showed that children generally find the social robot to be friendly, able to perceive them and not able to harm anyone (over 90% positive answers). The thematic analysis also revealed two important concepts:


**Table 2.**

*TTS features in both expressive and neutral conditions.*

*Towards Children-Centred Trustworthy Conversational Agents DOI: http://dx.doi.org/10.5772/intechopen.111484*

perceived autonomy, meaning children's perceptions about the robot's ability to act on its own even when they know the robot has to follow its programming, and shared responsibility, which involves working together towards a common goal, fostering a sense of understanding and teamwork among the group members.

Additionally, children were affected by the different robot behaviors, including the ones related to the CAs described above.


Overall, this experiment provides valuable insights into children's perceptions of an embodied CA and the impact of the DM (task performance) and DM + NLG (expressivity) modules. The results indicate that children had a positive opinion about the CA, but a low task performance affects children's social dynamics and a high expressivity increases its perception as a friend and children's aim to do homework with it. These examples help us to illustrate the impact CAs have on children and help to understand the role of CAs in children's lives.
