Memory enhancement is an improvement in a person's ability to recall or retain memories.     The experience of this effect can make it easier for a person to access and remember past memories at a greater level of detail when compared to that of everyday sober living. It can also help one retain new information that may then be more easily recalled once the person is no longer under the influence of the psychoactive substance.
Memory enhancement is often accompanied by other coinciding effects such as analysis enhancement and thought acceleration. It is most commonly induced under the influence of moderate dosages of stimulant and nootropic compounds, such as methylphenidate  , caffeine  , Noopept  , nicotine  , and modafinil  .
Different substances can enhance different kinds of memory with some considerable overlap. Generally, there are three types:
- Long-term memory: A vast store of knowledge and a record of prior events. 
- Short-term memory: Faculties of the human mind that can hold a limited amount of information in a very accessible state temporarily.   
- Working memory: Information used to plan and carry out behavior. Not completely distinct from short-term memory, it's generally viewed as the combination of multiple components working together. Measures of working memory have been found to correlate with intellectual aptitudes (and especially fluid intelligence) better than measures of short-term memory and, in fact, possibly better than measures of any other particular psychological process. Both storage and processing have to be engaged concurrently to assess working memory capacity, which relates it to cognitive aptitude.     
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