Abstract-As robots enter everyday life and start to interact with ordinary people the question of their appearance becomes increasingly important. Our perception of a robot can be strongly influenced by its facial appearance. Synthesizing relevant ideas from narrative art design, the psychology of face recognition, and recent HRI studies into robot faces, we discuss effects of the uncanny valley and the use of iconicity and its relationship to the self-other perceptive divide, as well as abstractness and realism, classifying existing designs along these dimensions. A new expressive HRI research robot called KASPAR is introduced and the results of a preliminary study on human perceptions of robot expressions are discussed.
I. MOTIVATIONSIt is an exciting time in robotics. Personal service robots, so long the science fiction dream, are becoming reality and are for sale to general consumers. Currently their uses are limited, but capabilities are improving, costs are coming down and sales are growing. In addition robots are finding a new place in society as toys, artificial pets [20], security guards, teachers [10], tour guides [24] and in search and rescue. They are finding use in areas as diverse as autism therapy [22], space exploration and research into cognition and biological systems [23].
A. RobotCubOne such research project that we are involved in at Hertfordshire is RobotCub, a multinational European project to build a humanoid child-size robot for use in embodied cognitive development research [23]. The RobotCub consortium consists of 11 core partners from Europe with collaborators in America and Japan, and the institutions involved are each working on specific areas of the robot design, engineering, developmental psychology and human-robot interaction. The software APIs and hardware plans will be published under open-source licenses, with the aim of creating a community using a common platform for robotic and cognitive research.
B. Designing Robots for UsersA previous study of people's expectations of a robot companion indicated that a large proportion of the participants in the test were in favour of a robot companion, especially one that could communicate in a human-like way [6]. Human-like behaviour and appearance were also considered important, but less so than human-like communication.
II. CONSIDERING DESIGN
A. The Extended Uncanny ValleyThe effect of the aesthetic design of a robot is an area that has often been neglected, and only in visual science fiction media or recently with the advent of commercial household robots has it been paid much attention. A notable exception is the 'uncanny valley' proposed by Masahiro Mori in the late 1970's [17], [5]. Mori proposed that the acceptance of a humanoid robot increases as realism increases. However there comes a point where, as the robot approaches perfect realism, the effect becomes instead very disturbing and acceptance plunges, because the robot starts to look not quite human or at worst like a moving corpse (Fig. 1). In theory the realism of both ap...