NCERT Solutions for Class 11 Psychology Chapter 7 Human Memory

Ans : The meaning of the terms encoding, storage and retrieval are as follows: 
(i) Encoding — It refers to the first stage of memory in which information is recorded and registered for the first time, in order to be used by memory systems. The external stimulus generates neural impulses in sensory organs during encoding which helps to receive the information and process it in different areas of the brain, in order to derive a meaning and represent it to be processed further. 
(ii) Storage — It is the second stage of memory in which the encoded information is stored and retained over a period of time to be used later. 
(iii) Retrieval — It is the third stage and refers to bringing the stored information into awareness in order to be able to perform the cognitive tasks. 

Ans : The information is processed through sensory. short-term and long-term memory systems in the following ways: 
(i) Sensory Memory — The incoming information enters through sensory memory which has a large capacity but is of very short duration of less than a second. It registers information from each of the senses with a reasonable accuracy. 
(ii) Short-term Memory — It refers to the system that holds small amount of information for a brief period of time. According to Atkinson and Shiffrin, the information is primarily encoded acoustically and unless it is rehearsed continuously, the information gets lost within 30 seconds. 
(iii) Long-term Memory — The information that survives in short term memory enters the long-term memory system. Once information enters here, it is never forgotten as it gets encoded semantically. Thus, it is a permanent storehouse of all the information. 

Ans : Maintenance rehearsals maintain the information through repetition. The information is lost when the repetition is discontinued. The short term system uses maintenance rehearsal to retain the information for a longer duration and it is carried through silent or vocal repetition. On the other hand. elaborative rehearsals associate the information that is to be retained with the already existing information in long-term memory. The permanence of new information is determined by the number of associations that is created around it. The incoming information is organised in many different ways by expanding the logical framework and creating a mental image. 

Ans : The hierarchical organisation in long term memory was suggested by Allan Collins and Roses Quillian. They observed that the knowledge in long-term memory is organised hierarchically in a networked structure. The elements of this structure are concepts known as nodes. The connections between nodes are called labelled relationships that indicate category membership or concept attributes. According to this view, all the knowledge can be stored at a certain level, which applies to all the members of a category without repeating that information at the lower levels in the hierarchy. It ensures efficient use of long-term memory through cognitive economy. 

Ans : Forgetting takes place because of a sharp drop in memory. The following are the different theories that have been put forward to explain the causes of forgetting: 
(i) Forgetting due to trace decay — It is the earliest theory of forgetting which assumes that the memory leads to modification in the central nervous system. This is akin to physical changes in the brain called memory traces. These traces later fade away and become unavailable when they are not used for a long time. 
(ii) Forgetting due to interference — This theory suggests that forgetting is due to interference between various information that are contained in the memory store. Interference occurs when the sets of associations that are formed during learning and memorising compete with each other tor retrieval. Proactive interference is a result of earlier information that interferes with subsequent learning while retroactive interference occurs when new information interrupts the recalling or earlier information. 
(iii) Forgetting due to retrieval failure — The contents of memory may become inaccessible either due to inappropriateness or absence of retrieval cues at the time of recall.