She specializes in the philosophy of mind and philosophy of psychology/cognitive science. Her research currently focuses on affect (emotions and moods), but she is also interested in questions about consciousness, representation, music, and personal identity. She has published in The British Journal for the Philosophy of Science, Philosophical Psychology, and Mind and Language. In addition to her primary research and teaching interests, Professor Sizer teaches topics in philosophy of art; applied ethics; the philosophy of language; philosophy of biology; and the relationship between science and religion. Professor Sizer is on the steering committee for the Culture, Brain, and Development Program at Hampshire College.