Can a Robot Smile? Wittgenstein on Facial Expression

Some researchers in social robotics aim to build ‘face robots’—machines that interact with human beings (or other robots) by means of facial expression and gesture. They aim, in part, to use these robots to test hypotheses concerning human social and psychological development (and disorders such as autism) in controlled, repeatable experiments. A robot may be said to ‘grin’ and ‘frown’, or to have ‘a smile on its face’. This is not to claim merely that the robot has a certain physical configuration or behaviour; nor is it to say merely that the robot’s ‘facial’ display is, like an emoticon or photograph, a representation of a smile or frown. Although researchers may refrain from claiming that their machines have emotions, they attribute expressive behaviours to them literally and without qualification. Wittgenstein said, however, ‘A smiling mouth smiles only in a human face’. Smiling is a complex conventional gesture. A facial display is a smile only if it has a certain meaning—the meaning that distinguishes a smile from a human grimace or facial tic, and from a chimpanzee’s bared-teeth display. In this paper I explore the implications of Wittgenstein’s remarks on expression for the claim that face robots can smile or frown

Can a Robot Smile? Wittgenstein on Facial Expression

Recent work in social robotics, which is aimed both at creating an artificial intelligence and providing a test-bed for psychological theories of human social development, involves building robots that can learn from ‘face-to-face’ interaction with human beings — as human infants do. The building-blocks of this interaction include the robot’s ‘expressive’ behaviours, for example, facial-expression and head-and-neck gesture. There is here an ideal opportunity to apply Wittgensteinian conceptual analysis to current theoretical and empirical work in the sciences. Wittgenstein’s philosophical psychology is sympathetic to embodied and situated Artificial Intelligence (see Proudfoot, 2002, 2004b), and his discussion of facial-expression is remarkably modern. In this chapter, I explore his approach to facial-expression, using smiling as a representative example, and apply it to the canonical interactive face robot, Cynthia Breazeal’s Kismet (see e.g. Breazeal, 2009, 2002). I assess the claim that Kismet has expressive behaviours, with the aim of generating philosophical insights for AI