This intervention arm involves a proactive companion robot delivered over 16 sessions, with a core emphasis on structured personalization to foster attachment.

Sessions 1-2 (Personalization Ritual): A healthcare professional facilitates a structured, four-phase co-design ceremony.

Sessions 3-16 (Autonomous Interaction): The co-designed robot is placed in the participant's room for autonomous interaction. It uses the personalized settings and exhibits default affectionate behaviors (e.g., approaching, responding to touch). To reinforce the bond, the healthcare professional uses scripted phrases attributing agency and memory to the robot (e.g., "[Robot's Name] remembers you"). Participants are encouraged to add one new "memory" per session for the robot to "store."

This arm involves the same robot for an equivalent duration and number of sessions as the co-design intervention arm, but without the personalization ritual or anthropomorphic framing.

Sessions 1-2 (Standardized Introduction): A healthcare professional introduces the same robot, demonstrating its three core, pre-programmed functionalities. The robot has a generic, fixed configuration with identical, pre-set eye color and voice pitch for all participants in this arm.

Sessions 3-16 (Neutral, Autonomous Interaction): The standard robot is placed in the participant's room for autonomous interaction. The key differentiator is the deliberately neutral and non-anthropomorphic framing by the healthcare professional

All groups will receive the usual community center services. The study district offers standard community-based programming, including group exercises, social events, and recreational activities, all of which are accessible to all residents. Participation is voluntary. To control for attention bias, healthcare professionals will conduct weekly 20-minute individual visits with participants in this group, totaling 16 sessions over the 4-week intervention period.

This arm utilizes the LOVOT robot within a structured protocol designed to foster a unique personal attachment through a co-design ceremony and anthropomorphic framing.

Personalization Ritual (Sessions 1-2): A healthcare professional facilitates a multi-phase personalization ceremony.

Autonomous Interaction (Sessions 3-16): The personalized LOVOT is placed in the participant's room. The robot consistently uses the participant-chosen voice and eye settings.

Measure the loneliness of participants at baseline before the intervention (T0), at the end of Week 2 (T1) following the initial interaction period, at the end of Week 8 (T2) upon completion of the core intervention phase, and at Week 12 (T3) and Week 24 (T4) to assess the sustained effects of the intervention.

Depressive Symptoms will be assessed using the Chinese version of the 15-item Geriatric Depression Scale (GDS-15) at baseline before the intervention (T0), at the end of Week 2 (T1) following the initial interaction period, at the end of Week 8 (T2) upon completion of the core intervention phase, and at Week 12 (T3) and Week 24 (T4).

General Self-Efficacy will be measured by the Chinese version of the General Self-Efficacy Scale (GSES) at baseline before the intervention (T0), at the end of Week 2 (T1) following the initial interaction period, at the end of Week 8 (T2) upon completion of the core intervention phase, and at Week 12 (T3) and Week 24 (T4).

The degree of engagement experienced during interactions will be captured using a scale that measures the level of absorption and focused engagement with the robot at pre- and post-intervention time points (T1, T2)