The Moral Uncanny Valley

Abstract Masahito Mori hypothesised that robots that look somewhat but not quite enough like humans are likely to arouse a sense of unease and discomfort. This hugely influential design hypothesis about robot appearance has been dubbed the ‘Uncanny Valley.’ I argue that there is a more general formulation of this principle that can be extended beyond the aesthetic domain of robot appearance. Specifically, I propose that there exists a Moral Uncanny Valley , which occurs when the behaviour of artificial agents mimics somewhat but not quite enough the moral behaviour of humans.The question then is: what should we do about the Moral Uncanny Valley? The solution Mori proposed for the appearance of robots is to avoid the Uncanny Valley and, given the inevitability of failing to reach the second peak, advised designers to design machines specifically to aim for the first peak: that is, to look less like humans. Instead of making a parallel recommendation in the moral case, I explore the dangers of being too comfortable around machines and thus the advantages of embracing the Moral Uncanny Valley. The sense of the uncanny brought about through what I call ‘discomfort by design’ can be useful for helping us to avoid making moral mistakes, like over-ascribing moral agency, patiency and responsibility.