Virtually everyone has occasionally wished that he or she could think faster, had a better memory, or was simply smarter. It is possible to improve these facets of cognitive function through practice, but most people are looking for an easier solution. At the beginning of the twenty-first century, the answer is usually imagined to be in the form of a pill.

Cognition has many elements. Key aspects of cognition include sensory perception, attention and concentration, immediate (or working) memory, and long-term memory. More complex and integrated facets of cognition include abstract reasoning and planning. Thus, there are a number of ways for pharmacological treatments to enhance cognition. However, for most people cognitive enhancement is synonymous with having a better long-term memory, so this topic is the primary focus of this entry.

Memory itself is a complex phenomenon that is still not completely understood by the medical...