  In this paper, we explore how techniques from soft robotics can help create a
new form of robot expression. We present Sprout, a soft expressive robot that
conveys its internal states by changing its body shape. Sprout can extend,
bend, twist, and expand using fiber-embedded actuators integrated into its
construction. These deformations enable Sprout to express its internal states,
for example, by expanding to express anger and bending its body sideways to
express curiosity. Through two user studies, we investigated how users
interpreted Sprout's expressions, their perceptions of Sprout, and their
expectations from future iterations of Sprout's design. We argue that the use
of soft actuators opens a novel design space for robot expressions to convey
internal states, emotions, and intent.
