NCERT Solutions for Chapter 7 Human Memory Class 11 Psychology

Encoding: It is the first stage which refers to a process by which information is recorded and registered for the first time so that it becomes usable by our memory system.

Storage: It is the second stage of memory. Information which was encoded must also be stored so that it can be put to use later. Storage, therefore, refers to the process through which information is retained and held over a period of time.

Retrieval: It is the third stage of memory. Information can be used only when one is able to recover it from her/his memory. Retrieval refers to bringing the stored information to her/his awareness so that it can be used for performing various cognitive tasks such as problem solving or decision-makin

According to the Stage Model, there are three memory systems: the Sensory Memory, the Short-term Memory and the Long-term Memory.

Sensory Memory: The incoming information first enters the sensory memory. Sensory memory has a large capacity. However, it is of very short duration, i.e. less than a second. It is a memory system that registers information from each of the senses with reasonable accuracy. Often this system is referred to as sensory memories or sensory registers because information from all the senses are registered here as exact replica of the stimulus.

Short-term Memory: Information that is attended to enters the second memory store called the short-term memory (abbreviated as STM), which holds small amount of information for a brief period of time (usually for 30 seconds or less). Atkinson and Shiffrin propose that information in STM is primarily encoded acoustically, i.e. in terms of sound and unless rehearsed continuously, it may get lost from the STM in less than 30 seconds. Note that the STM is fragile but not as fragile as sensory registers where the information decays automatically in less than a second.

Long-term Memory: Materials that survive the capacity and duration limitations of the STM finally enter the long-term memory (abbreviated as LTM) which has a vast capacity. It is a permanent storehouse of all information that may be as recent as what you ate for breakfast yesterday to as distant as how you celebrated your sixth birthday. It has been shown that once any information enters the long-term memory store it is never forgotten because it gets encoded semantically, i.e. in terms of the meaning that any information carries.

Maintenance rehearsals:
Maintenance rehearsals are the kinds of rehearsals simply maintain information through repetition and when such repetitions discontinue the information is lost. They are carried through silent or vocal repetition.

Elaborative rehearsals:
These rehearsal attempts to connect the ‘to be retained information’ to the already existing information in long-term memory. For example, the task of remembering the meaning of the word ‘humanity’ will be easier if the meanings of concepts such as ‘compassion’, ‘truth’ and ‘benevolence’ are already in place. The number of associations you can create around the new information will determine its permanence. In elaborative rehearsals one attempts to analyse the information in terms of various associations it arouses. It involves organisation of the incoming information in as many ways as possible.

Declarative memories:
All information pertaining to facts, names, dates, such as a rickshaw has three wheels or that India became independent on August 15 1947 or a frog is an amphibian or you and your friend share the same name, are part of declarative memory. Facts retained in declarative memory are amenable to verbal description.

Procedural memories:
Procedural memory, on the other hand, refers to memories relating to procedures for accomplishing various tasks and skills for example- how to ride a bicycle, how to make tea or play basketball etc. The contents of procedural memory cannot be described easily.

Depending upon how much time people take in responding to questions such as these, the nature of organisation in long- term memory has been inferred.

The most important unit of representation of knowledge in long-term memory is a concept. Concepts are mental categories for objects and events, which are similar to each other in one or in more than one way. Concepts may also get organised in schema. They are mental frameworks which represent our knowledge and assumptions about the world.

In the year 1969, Allan Collins and Ross Quillian published a landmark research paper in which they suggested that knowledge in long-term memory is organised hierarchically and assumes a network structure. Elements of this structure are called nodes. Nodes are concepts while connections between nodes are labelled relationships, which indicate category membership or concept attributes.

Forgetting refers to loss of stored information over a period of time. After a material is learnt, there is a sharp drop in its memory and then the decline is very gradual. Forgetting has been explained as resulting from trace decay and interference. It may also be caused due to absence of appropriate cues at the time of retrieval.

Forgetting due to Retrieval Failure:
Forgetting can occur not only because the memory traces have decayed over time (as suggested by the disuse theory) or because independent sets of stored associations compete at the time of recall (as suggested by the interference theory) but also because at the time of recall, either the retrieval cues are absent or they are inappropriate. Retrieval cues are aids which help us in recovering information stored in the memory. This view was advanced by Tulving and his associates who carried out several experiments to show that contents of memory may become inaccessible either due to absence or inappropriateness of retrieval cues that are available/employed at the time of recall.

Forgetting due to Interference:
Interference theory which suggests that forgetting is due to interference between various information that the memory store contains. This theory assumes that learning and memorising involve forming of associations between items and once acquired, these associations remain intact in the memory. People keep acquiring numerous such associations and each of these rests independently without any mutual conflict. However, interference comes about at a time of retrieval when these various sets of associations compete with each other for retrieval.

According to Bartlett memory is a constructive process. Using meaningful materials such as texts, folk tales, fables, etc. Bartlett attempted to understand the manner in which content of any specific memory gets affected by a person’s knowledge, goals, motivation, preferences and various other psychological processes. He conducted simple experiments in which reading of such stimulus materials was followed by fifteen minutes break and then the participants of his experiment recalled what they had read. Bartlett used the method of serial reproduction in which the participants of his experiments recalled the memory materials repeatedly at varying time intervals. While engaging in serial reproduction of learned material his participants committed a wide variety of ‘errors’ which Bartlett considered useful in understanding the process of memory construction. His participants altered the texts to make them more consistent with their knowledge, glossed over the unnecessary details, elaborated the main theme and transformed the material to look more coherent and rational. In order to explain such findings, Bartlett invoked the term schema, which according to him ‘was an active organisation of past reactions and past experiences’. Schemas refer to an organisation of past experiences and knowledge, which influence the way in which incoming information is interpreted, stored, and later retrieved. Memory, therefore, becomes an active process of construction where information is encoded and stored in terms of a person’s understanding and within her/his previous knowledge and expectations.

Mnemonics are strategies for improving memory. There are different plans to improve memory. One such plans is as follows:
Engage in Deep Level Processing:  If you want to memorise any information well, engage in deep level processing. Craik and Lockhart have demonstrated that processing information in terms of meaning that they convey leads to better memory as compared to attending to their surface features. Deep processing would involve asking as many questions related to the information as possible, considering its meaning and examining its relationships to the facts you already know. In this way, the new information will become a part of your existing knowledge framework and the chances that it will be remembered are increased.