Memory continues to play an important role in cognitive science today, especially with the work of the Canadian psychologist Endel Tulving, who proposed that human beings store memories in two distinct ways: short-term (STM) and long-term (LTM). However, because the latter requires longer periods of time to access, researchers began studying how to improve long-term memory through mnemonic strategies such as imagery, chunking, or spaced retrieval.
Tulving also identified two categories of memory: episodic and semantic. Episodic memories are those that involve personal experience, whereas semantic memories are those related to facts and knowledge. Thus, episodic memories are stored in an area of the brain called the hippocampus, near the amygdala (a part of the limbic system) and the prefrontal cortex (which helps control emotions). Semantic memories are stored in the neocortex, together with the visual areas of the brain.