Recent advances in brain imaging techniques mean that it is now possible to examine how the brain is functioning when an individual carries out a social ‘task' or exchange. Hyperscan functional magnetic resonance imaging (h-fMRI) i.e. the simultaneous measurement of brain activity in two socially interacting people, is an important development for autism research. The present study aims to combine computational approaches with functional brain imaging to examine how the neural systems involved in social interactions go awry to yield the social deficits seen in autism spectrum disorders. Specifically, a social exchange task called an iterated Trust game and h-fMRI will be used to characterize neural and behavioral responses to social signals in individuals with autism as they participate in dynamic social exchanges with a human partner. The study will also use a ‘computer partner' to examine differences in the sensitivity of individuals with autism spectrum disorder to signals of social reciprocity - the computer partner will be made to vary its responses from ‘human-like and socially responsive' to ‘random and not socially-responsive'. What this means to people with autism: The proposed work promises not only to contribute to the current understanding of the neural substrates of autism and its social sequelae but to provide a technological way to define new phenotypes and ultimately identify specific subtypes of autism spectrum disorders. This could inform the design, target, and implementation of new diagnostic and intervention protocols.