Building Trust and Rapport With Social Robots: Insights From Professor Hsiu-Ping Yueh

In the third post for our Healthy Aging® Month video series, Hsiu-Ping Yueh, PhD from National Taiwan University gives an overview of her team’s research published in JMIR Aging. Joining her in the video are two Kebbi social robots, her "co-stars" in studying how technology can tackle social isolation in older adults.

In her video, Hsiu-Ping Yueh highlights that while social robots offer a promising solution to combat loneliness, a robot only helps if the interaction feels genuinely good. Her team's study explored two critical nonverbal cues: facial expressions and inclusive turn-taking behavior. Professor Yueh reveals three key findings: smiles matter immensely for building trust; a warm, smiling face can partially compensate when a robot behaves exclusively; and surprisingly, older adults actively chose to engage more with the ignoring robot out of a deeply held sense of fairness and empathy.

Decoding Human-Robot Interactions in Healthy Aging

The video builds directly on the findings of a novel mixed-factorial experiment published in JMIR Aging, titled "The Influence of Robot Facial Expression and Inclusion Behavior on Rapport and Trust in Older Adults: Mixed-Factorial Experimental Study". The study evaluated how 53 community-dwelling older adults (averaging 70 years old) responded to two humanoid Kebbi robots displaying different combinations of facial expressions (happy vs. unhappy) and interaction styles (inclusive vs. exclusive) during an adapted group game.

The research demonstrated that positive facial expressions significantly boosted robot acceptance, rapport, and trust with medium-to-large effect sizes. The study uncovered a powerful interaction effect: while inclusive behavior created baseline social engagement, a smiling face became crucial under exclusive conditions—meaning a warm facial expression can soften negative or ambiguous robot behavior.

Older Adults as Prosocial Caretakers of Technology

Perhaps the study's most surprising contribution lies in the behavioral responses of the participants. Contrary to younger cohorts in previous studies who favored inclusive robots, older adults deliberately selected the exclusive robot more frequently during gameplay. Qualitative interviews revealed that participants were guided by strong values of equity and turn-taking, making sure the "ignoring" robot was included so everyone got a turn.

These findings carry vital implications for developers creating assistive devices for aging populations. Beyond engineering inclusive behaviors and warm visual cues, social robot designers must recognize that older adults bring deeply held social schemas and prosocial values into these interactions. Rather than viewing robots as mere machines, older adults treat them as social entities deserving of fair treatment—offering an inspiring blueprint for technology designed to foster meaningful human connection.

While social robots offer innovative ways to combat loneliness, technology is only one piece of the healthy aging puzzle. Next up in our series, Professor Eliza Wong demonstrates how a simple, gamified tabletop game can foster deep, meaningful conversations across human generations.