Choosing a mate is one of the most important decisions an animal can make. The fitness costs and benefits of mate choice have been analyzed extensively in the context of sexual selection, and the neural and hormonal bases of mate choice have provided insights into how animals make such decisions. Less attention, however, has been given to higher-level cognitive processes involved in this decision making. The assumption that animals choose mates predictably and rationally is an important assumption in both ultimate and proximate analyses of mate choice. It is becoming clear, however, that basic assumptions of rationality are often violated and unpredictable nonlinearities often emerge in mate choice. Here we review studies in which cognitive analyses seem to play an important role in the following contexts: auditory grouping; Weber’s law; competitive decoys; multimodal communication; and, perceptual rescue. The sum of these studies suggest that mate choice decisions are more complex than they might seem and suggest some caution in making assumptions about evolutionary processes and simplistic mechanisms of mate choice.