This chapter asks how voters react to political messaging and, crucially, sometimes change their minds. It begins by reviewing experimental psychology, neuroimaging, and artificial intelligence research showing that the brain reasons in two distinct ways: Recognizing patterns (fast or Type 1 thought) and constructing logical arguments (slow or type 2 thought). It then argues that the first mode almost always dominates political thought. The paradox is that humans have evolved to feel pleasure both in confirming old patterns and in being surprised by new ones. This means that while political messaging is often repetive, humans are also susceptible to messages that feature large departures from current orthodoxies. Because of majority rule, politicians will normally prefer messages that appeal to large numbers of voters. This explains how even highly-polarized electorates can sometimes realign around new issues to restore a more centrist politics.