Memory is one of the least investigated human abilities. Memory is the process of storing experiences in the brain and recalling them later. Many scientists believe that there are two levels of memory. One level is short-term memory, or working memory. The other level is long-term memory, or permanent memory. Short-term memory lasts about 15 to 30 seconds. Long-term memory can last days, months, years, or a lifetime.
Psychologists, philosophers, physicians and naturalists have been trying to penetrate this unexplored territory for centuries. Memory is a trace in the nerve substance of the brain. It is believed that nucleic and ribonucleic acids are involved in the process.