<p>As robots assist in various tasks like personal training, lifting, entertaining, and aiding in daily activities that requires physical human-robot interaction (pHRI), enhancing users’ perception of the robot and engagement in the interaction is crucial. This can be achieved by endowing robots with non-verbal social cues, like facial expressions, to improve the user experience. This study examines the impact of facial emotional expressions on users’ perception of a robot and their engagement levels, in a light physical exercise scenario, among younger adults. We conduct a comparative analysis between younger and older adults using data from both the current and an earlier study in the same setting. Additionally, we evaluate the reliability of common standardized questionnaires for assessing users’ perception of robots in pHRI across different age groups to ensure accurate measurements. While our findings showed that levels of engagement were unaffected for both younger and older adults, a contrast emerged in their perception of the robot: older adults viewed robots with facial expressions as less competent than those without, whereas younger adults’ perception remained unaffected by the presence or animacy of facial expressions. Both age groups consistently rated the robot lowest across various dimensions of user perception and engagement when it had dynamic facial expressions and highest when it exhibited none. Contrary to existing literature, our results suggest that preferences in pHRI may vary based on robot type (humanoid vs. cobots) and the context (social vs. collaborative). We hypothesize that these factors significantly impact users’ communication preferences.</p>