Memory can be defined as the capacity to keep information available for later use. The process of memory can be divided in to the four aspects -learning, retention and forgetting, and retrieval. The initial storage of information is called learning, keeping the new information available is called retention, the loss of new information over a period of time is called forgetting and utilization of stored information is called retrieval.
According to psychologists there are four kinds of learning. Classical conditioning is the simplest kind of learning. Ivan Pavlov studied it during the early 1900. He offered a dog food and at the same time rand a bell. The sight of food made the dog’s mouth water. Pavlov called this unconditional response because it was not learned. Soon, however, ringing the bell was enough to cause the dog’s mouth to water. This is called conditional response. Classical conditioning is often called respondent learning.
Another form of learning is called instrumental learning. Often a person learns to do something as a result of what happens after the person does it.
Multiple response learning is the third type and it takes place when a skill is learned. A sequence of simple things must first be learned. Using a type writer is our kind of multiple-response learning. At first, a person has to type letter by letter. With practice, the person learns to type word by word or phrase by phrase.
Fourth type of learning is insight learning. It means solving a problem through understanding how the different parts of a problem fit together. A simple example is that of a young child wanting to climb on the top of a table. The child may use a stool to get on to the chair and then use the chair to climb onto the table.
There are two basic theories to explain the process how we memorise events. According to one theory, memory is said to be stored in the brain as a memory trace. When we learn or experience something, impulses are generated in the nerves of the brain. These impulses impart their effects in the brain in the form of a record. According to the other theory, sensations created by learning produce some permanent changes in the brain which remain there in the form of memory. According to some biologists, the R.N.A. (ribo-nucleic acid) present in the brain keeps the record of events. It has been observed that the quantity of R.N.A. present in the brain keeps on increasing from the age of three to the age of forty. During these years, the memory of the man also increases. The quantity of R.N.A. is almost constant from the age of 40 to 55 or 60. Therefore man's memory is almost consent during this period. After the age of 60, the quantity of R.N.A. starts decreasing and so does the memory.
The only effective way of remembering something is to repeat it many times. Interest is very important. Boring things are much more difficult to remember than something that we understand and are interested in. Motivation or desire to do something, is also important.