Findings

The results from this study indicate that children were willing to interact with a robot in an interview scenario and did so in a similar way to how they interacted with a human interviewer. Furthermore, the amount of information that children provided to KASPAR was also very similar to the information they provided to the human. This was assessed by measuring the children’s use of keywords which we found to be similar in both the robot and human conditions. In addition, the analysis of the key points indicated that there were no significant differences in the information the children provided to KASPAR and the human interviewer. There were however statistically significant differences in both the duration of the interviews and the eye gaze toward the interviewer. The difference in the duration of the interviews can be explained by the additional time it took for the robot to respond, this was due to the technical limitations of the robot. In our data analysis we found that the robot took significantly longer to respond to the children and this is why the interviews with the robot took longer (Table 3). To confirm this we also checked by combining the time that the children spent talking, the time that the interviewer spent talking and the time that the children took responding to the robot, and this result also confirmed that the additional time taken by the interviewing the children was due to the time it took the robot to respond. Potentially this could have influenced the results of the study if this delay had caused the children to feel a disconnection in the human-robot interaction experience. However, this is not supported by our results. Note, the robot would still blink periodically during the brief periods of delays, thus maintaining the visual appearance of movement and presence of the robot.

In this study there was considerable variation in the durations of the interviews. This was due to the children all being very different in terms of how they spoke and how much information they gave. Some children were shy and would not talk much at all whilst others were very confident and would talk for a long time. Future investigations could study such individual differences in more depth, e.g. whether children’s personality traits influence their responses in interviews with a human and a robot. Previous studies have shown the influence of participants’ personality traits in human-robot interaction, e.g. [40], [46], [47].

The statistically significant difference in the durations of the interviews was due to the operation of the robot which can be confirmed from the results of the interviewer response durations (Table 3). Getting KASPAR to respond to the children takes longer than it does for a human interviewer present in the room because finding the appropriate key to respond with takes longer, despite extensive training of the operator/experimenter prior to the experiment. The results show that children looked at KASPAR more than at the human (consistent with our expectations concerning RQ1), possibly because the robot was a novel object to the children and therefore they may have been more interested in KASPAR than the human interviewing them. Ascertaining that children will respond to a robot in an interview scenario as well as to a human is an important first step in establishing that robots could be a useful tool for interviewing children.

The children’s verbal responses to were very similar in both conditions with regards to word count, filler words, key words and key points. Furthermore the children’s word count relative to the interviewers word count was similar. Both interviewers followed the same interview structure and asked the same questions. However, the interviewers are very different in terms of their nature (robot/human), so such a similarity in children’s responses in both conditions is very encouraging for developing robots as interviewing tools for children. Although the results from our study show that the children interacted with the robot in a similar manner to which they did with a human, and the information they provided is also similar, there are potential advantages a robot could have over a human interviewer. When the police are conducting interviews with children that have been through a stressful or traumatic ordeal it can be difficult for the human interviewer to maintain their composure without subtly and unintentionally indicating their thoughts and feelings. Sometimes the information that a child reveals in an interview can be quite shocking or surprising. The 2011 ABE states “the interviewer should not display surprise at information as this could be taken as a sign that the information is incorrect” [48] This can be quite difficult for a human interviewer but would be easy for a robot whose expressions are explicitly controlled, and this is one of the reasons why a robotic interviewer may have an advantage over a human interviewer in certain situations. It is also important that the interviewer does not appear to assume that someone is guilty “So far as possible, the interview should be conducted in a ‘neutral’ atmosphere, with the interviewer taking care not to assume, or appear to assume, the guilt of an individual whose alleged conduct may be the subject of the interview” [49]. Using a robot to interview a person could eliminate any of the subtle unintentional signs in body language that a human interviewer may give away, while the body language of the robot can be fully and precisely controlled by the interviewer. In addition to this the ABE states “research shows that a person’s perceived authority can have an adverse effect on the witness, especially with respect to suggestibility” [50]. Using a small child sized robot could potentially eliminate this problem because the robot is clearly not an adult and may not be viewed in the same way.

The children’s similar use of filler words may indicate that the children found talking to KASPAR very similar to talking to the human in terms of comfort. In some respects measuring filler words could provide a better indicator of a child’s comfort in a particular situation than a word count. The questions in the interview were focused on an event that took place on one particular day and the interviews were one week apart therefore the amount the children would remember would inevitably change. The amount of filler words the children used is likely to be more consistent with the child’s level of comfort and the number of questions asked. Some research investigating linguistic disfluencies suggests that the use of filler words could be linked to the difficulty of planning what to say [51], [52]. Whereas other research suggests that filler words my serve a communicative function to help coordinate linguistic interactions [53], for example, fillers may be used so an individual is not interrupted before they can speak their next sentence [54], [55]. There is also some evidence showing that an increased number of fillers and longer pauses occur before an uncertain answer is given [56], [57]. High disfluency has been associated with anxiety [58]. The children’s equal use of filler words in the present experiment may reflect that their comfort levels were the same with both interview partners.

Our analysis of the key points revealed that in our experiment there were no significant differences in the information the children provided to a robot compared to a human interviewer. However the analysis of the key points for each category does show that the questions in the interviews varied in difficulty. For example the children consistently named the winners of the event but often name fewer judges, even though there were more judges than winners (Table 5). This highlights that the questions in these interviews varied in difficulty.

We found no significant differences in the amount the children spoke to KASPAR, the number of keywords the children used with KASPAR, or the amount of key points the children revealed to KASPAR, compared to the human (contrary to our expectations concerning RQ2 which expected clear preferences either towards the robot or the human interviewer). However, this finding is very encouraging for the future use of robots, as it could be interpreted in such a way that children actually make no difference between human and robot interviewers in this respect and that therefore robot interviewers (i.e. robots as interviewing tools in the hands of experts remotely conducting the interview via the robot) could, with appropriate adjustments, be used as a valuable complement in interviews e.g. with social services and police.

Concerning the effect of the order of the experimental conditions, only two of the twenty-nine measures contained statistically significant differences, these were the interviewer response duration and the number of children that remembered and stated that they had taken part in a poster making activity (Tables S3, S5). It is likely that the additional time in the response duration of the interviewers is because over time the lead investigator became more comfortable and used to the interview scenario and as a result took more time responding in the later stages of the study. Although there was a statistically significant difference the mean difference is only 4.05 seconds and does not appear to have affected the interactions or the results of the study. The results of the poster activity reveal that there was a significant difference in the number of children that remembered and stated taking part in the poster making activity. The results show that more children stated taking part in a poster activity in the first phase of the interviews than the second. This is possibly because the poster activity was not the main focal point of the event and the questions in the interviews did not focus on this aspect of the event.

Generally, the findings from this study are consistent with the HRI literature as the children were happy to talk to and interact with KASPAR. The increased levels of eye gaze also suggest that the children were very interested in KASPAR. This study confirms and builds on the findings of the study by Bethel et al. [21] which found that children are equally likely to share a ‘secret’, or other valuable information, with a robot as they are a human. The context of the interaction and age ranges slightly differ in the two studies but the basic concept of children talking to a robot is the same.