Emotional Expression in Low-Degrees-of-Freedom Robots: Assessing Perception with Reachy Mini

2026-05-12

AI Summary

This study investigates how humans perceive emotions conveyed by low-degree-of-freedom, non-anthropomorphic robots—such as the Reachy Mini—under conditions of extremely limited expressive capability. In an online within-subjects experiment, participants viewed videos of the robot displaying various emotional expressions and rated their accuracy in identifying the intended emotion, along with assessments of valence, arousal, and social perception traits. Results indicate that while overall emotion recognition accuracy was modest, anger, sadness, and interest were more readily identified. Core affective dimensions, particularly valence and arousal, remained effectively communicable, and positive expressions significantly enhanced perceptions of the robot’s warmth and sociability. This work presents the first systematic evaluation of emotional expressivity in highly constrained, non-humanlike robotic platforms, revealing their potential influence in social interaction contexts.

Abstract

Emotion expression is central to human--robot interaction, yet little is known about how people interpret affect on robots with sparse, non-anthropomorphic expressive capabilities. This study examined how people perceive emotional expressions displayed by Reachy Mini (Pollen Robotics and Hugging Face), a low-degree-of-freedom (low-DoF) robot with a constrained and distinctly non-human expressive repertoire. In an online within-subjects study, 100 participants viewed 10 short video clips of Reachy Mini expressing different emotions and, for each clip, identified the perceived emotion, rated its valence and arousal, and evaluated the robot on social-perception traits. Exact emotion recognition was modest overall and varied considerably across expressions, with anger, sadness, and interest recognized more reliably than emotions such as love, pleasure, shame, and disgust. However, participants were generally more successful at recovering broader affective meaning than exact emotion labels, particularly along valence and arousal dimensions. Emotional expressions also shaped social evaluation, as positive expressions were perceived as warmer and more sociable than negative ones, and animacy varied less across conditions. These findings suggest that even constrained robotic expressions can communicate affective meaning and influence social impressions, positioning Reachy Mini as a useful benchmark for studying affective communication in low-DoF robots.

Problem

• Emotional Expression
• Low-Degrees-of-Freedom Robots
• Human-Robot Interaction
• Affective Perception
• Non-anthropomorphic Robots

Innovation

• low-degree-of-freedom robot
• emotional expression
• affective communication
• social perception
• non-anthropomorphic design