Nouns and Phrases Date of Submission

Recent advances in functional Magnetic Resonance Imaging (fMRI) offer a significant new approach to studying semantic representations in humans by making it possible to directly observe brain activity while people comprehend words and sentences. In the proposed work, we used fMRI to study the cortical systems that underpin semantic representation while people comprehended linguistic concepts like concrete objects, adjective-noun phrases, or noun-noun concept combinations. The thesis of this research is that the distributed pattern of neural activity encodes the meanings of linguistic concepts and intermediate semantic representation can be used to model how brain composes the meaning of words or phrases in terms of more primitive semantic features. In an object-contemplation task, participants were presented with line drawings and/or text labels of objects and were instructed to think of the same properties of the stimulus object consistently during multiple presentations of each item. By learning 1) the correspondence between features in semantic models and neural activity, and 2) the semantic composition model that governs how words are combined to form phrases, this work enables a predictive theory that is capable of extrapolating the model of the neural activity to previously unseen words and phrases.