Q: It is well known that human beings have a very large memory capacity. Then why do we forget things? Children always require to revise their lessons thoroughly before examinations even if the chapters have been studied with great attention in the past. Adults too forget to accomplish tasks as per their schedule. If we really have a large memory capacity, then why do we forget?

A:It is believed that there are three distinct processes of memory - encoding process, storage process and retrieval process. Encoding is the process of receiving sensory input and transforming it into a form or code which can be stored; storage is the process of actually putting the coded information into memory; and retrieval is the process of gaining access to stored, coded information when it is needed. It is also believed that the human memory is divided into two major parts- one that is temporary and limited in its capacity, this is the short term memory and the other that is more lasting and ample which is the long term memory. For the short term memory information to become long term organized memory, it requires attention, repetition and associated ideas within a few minutes or it will be lost. Retrieving of information is aided by retrieval cues or reminders, which direct the memory search to the appropriate part of the long term memory library. Therefore when these retrieval cues are not found, the sought for item in our long term memory is also lost and it is said that one has forgotten. It may be that much of what we think we have forgotten does not really qualify as forgotten as it may not have even reached the short term memory from the sensory register or was never encoded and stored in the long term memory due to lack of attention in the first place.