# Designing Social Robots with LLMs for Engaging Human Interaction
## 5 Evaluation with Older Adults
### User Perceptions and Design Insights  
Participants responded positively to the robot's language capabilities, voice tone, and conversational adaptability. Topics such as hobbies, family, daily routines, and past experiences emerged organically, as shown in Figure 5. Unlike in the young adult evaluation--where repetition was more frequently noted--older adults generally accepted topic persistence and made fewer negative comments about conversational redundancy. This may reflect differences in expectations or the novelty of the interaction.  
All participants described the robot as comforting, with four participants comparing it to pets or childhood toys. Three participants who reported experiencing loneliness said they would enjoy having [PERSON] at home. P6 remarked, _\"If I feel alone or sad, I do feel that you could confide in it\"_. P4 added, _\"If I had a robot like this, I would definitely have a chat with it every morning\"_. Even among those who did not express personal interest in using the robot, most recognised its potential value for others, such as friends or individuals living with loneliness or dementia. These reflections align with prior HRI findings that emphasise the role of companionship and social presence in fostering long-term engagement [12].  
Voice quality and tone were frequently praised, especially the warmth and clarity of the ElevenLabs-generated voices. Although slower responses were generally tolerated, participants were sensitive to interruptions and valued clear conversational cues. As P2 noted, _\"Just like people, [PERSON] sometimes interrupts\"_. P7 added, _\"Considering it's a robot, its slightly slower pace is understandable\"_.  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline
**Pt.** & **Sess.** & **Dur. (min)** & \
\begin{tabular}{c} **Avg. Resp. T.** \\ **(s)** \\ \end{tabular} & **Turns** & **Interr. (\%)** &
\begin{tabular}{c} **STT Accu.** \\ **(\%)** \\ \end{tabular} \\ \hline \multirow{2}{*}{P1} & I & 10:49 & 6.96 & 20 & 10.0 & 95.3 \\  & II & 07:58 & 6.73 & 13 & 7.7 & 94.3 \\ \hline \multirow{2}{*}{P2} & I & 10:26 & 7.07 & 18 & 38.9 & 82.3 \\  & II & 14:35 & 7.14 & 20 & 20.0 & 86.6 \\ \hline \multirow{2}{*}{P3} & I & 07:57 & 6.69 & 12 & 25.0 & 88.7 \\  & II & 06:36 & 6.94 & 10 & 10.0 & 88.4 \\ \hline \multirow{2}{*}{P4} & I & 16:31 & 7.18 & 30 & 10.0 & 91.3 \\  & II & 12:01 & 7.05 & 19 & 5.2 & 92.3 \\ \hline \multirow{2}{*}{P5} & I & 08:01 & 6.55 & 14 & 15.4 & 86.5 \\  & II & 06:27 & 6.67 & 12 & 8.3 & 89.4 \\ \hline \multirow{2}{*}{P6} & I & 09:08 & 6.82 & 16 & 12.5 & 91.2 \\  & II & 10:03 & 6.55 & 18 & 5.5 & 92.5 \\ \hline \multirow{2}{*}{P7} & I & 15:34 & 7.25 & 28 & 5.5 & 94.2 \\  & II & 09:48 & 7.12 & 18 & 0.0 & 95.4 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Interaction metrics across participants: duration, responsiveness, interruptions, and STT accuracy.  
Despite overall positive reactions, several challenges emerged. Some participants expressed minor confusion when the robot responded vaguely or failed to maintain the thread of conversation. In one instance, a participant asked the robot to sing, only to receive a spoken recitation of lyrics, prompting the comment, _\"It recited the lyrics instead of actually singing\"_. These moments highlight the need to better manage expectations and clarify system capabilities to avoid perceived breakdowns. Additionally, while repetition was less problematic for older adults than younger users, occasional fallback phrasing and overly generic questions were still noted.  
In summary, this exploratory evaluation demonstrated the system's feasibility and perceived value among older adults. It also underscored the importance of clear turn-taking cues, culturally adapted voices, and expectation alignment for sustained interaction. These findings complement the earlier insights gathered from younger adults and inform the key design considerations discussed in the following section.