“Although there have been many researches on artificial haptic-sensory skin and discussions of materials for facial expression, we can find few trials related to expressions on surface of robots.”
Explain a research team from Dr. Tomoko Yonezawa’s lab at Kansai University Osaka, Japan, prompting them to become one of the first teams worldwide (perhaps the first) to develop robotic goosebumps.
“The goose bumps are caused both of external stimuli such as cold temperature and internal state such as fear. The testbed of the goose-bump skin was implemented on the robot’s arm.”
The video above goes some way towards describing the project.
See: Involuntary expression of embodied robot adopting goose bumps in HRI ’14 Proceedings of the 2014 ACM/IEEE international conference on Human-robot interaction.