• The study of learning emphasisesacquisition process while the study of memory emphasise on retention process.

• Memory is studied in terms of mental processes involved in storing & retrieving information.

Memory• Human Memory is a system for storing and

retrieving information which is acquired through our senses.

• It consists not of one but of many systems which range ina) Storage duration from fractions of a second up to a lifetime and inb) Storage capacity from tiny buffer stores to the long-term memory system.

Memory

• Memory is our cognitive systems for storing and retrieving information.

• We can form memories of information, events, emotions, & sensations.

• It is not a perfect system.

Memory

TheoriesTheoriesTheory of General Memory Functions

• Three distinct processes1. Encoding Process: Transformation of a

physical stimulus into a form that human memory accepts.

2. Storage: Retention of information that is encoded.

3. Retrieval: Recovering information from storage.

Information-Processing Theory(Richard C. Atkinson & Richard M. Shiffrin, 1968)

Sensory Input

Some information is not transferred to STM.It is forgotten.

Some materials are nottransferred to LTM.They are forgotten.

Factors like decay &interference may lead toForgetting from LTM.

Some materials arerehearsed & kept in STM.

RehearsalRetrieval

Sensory Memory0.25 sec.-2 sec.

Short Term Memory20-30 sec.

Long Term Memory

Information Processing Model• Right kind of information processing is more

important than intentional goal of learning.• “Who am I?” - autobiographical memory:

Record of the experiences of a lifetime that go together to create myself as a person.

• “What do I know?” - semantic memory:• “How do I learn?”• General information about the world• Best method of efficient retrieval depends on how

material is stored.

Level of Processing Theory((CraikCraik & Lockhart, 1972) (& Lockhart, 1972) (CraikCraik & & TulvingTulving, 1975), 1975)

Incoming InformationIncoming InformationLevel 1: Perception

Level 2: StructuralLevel

Level 3: SemanticLevel

Dep

th o

f pro

cess

ing

Amount of elaboration

Neural Network Perspective• Parallel distributed processing• Collections of modules process

information in different ways simultaneously

• Activation & spreading• Memory is making or strengthening

interconnections between these modules

A Model of MemoryEnvironmental Input

Sensory RegisterVisual

Auditory

Haptic

Short-Term MemoryWorking Memory

Control Processes:Rehearsal

CodingDecision

Retrieval Strategies

Long-Term Memory

Response Output

Sensory Memory• Visual, hearing, smell, taste, touch

• The storage of sensory information provides a microcosm of the memory system as a whole.

Sensory Memory• It begins with the systems of iconic and echoic

memory that store visual and auditory information over a matter of milliseconds, as part of the processes involved in perception.

• Both of these appear to have characteristics that allow the initial stimulus to be prolonged, probably so as to ensure that adequate later processing is possible.

Sensory Memory• VISUAL MEMORY

– Iconic memory– Short-term visual memory– Flashbulb memory– Long-term visual memory

• AUDITORY MEMORY– Echoic memory– Short-term auditory memory– Long-term auditory memory

Sensory Memory

Iconic MemoryIconic Memory

• Holds information for up to 1-2 seconds.

• 11-16 items can be hold.

Echoic MemoryEchoic Memory

• Holds information for up to about 4-5 seconds.

Sensory Memory: Visual

Sensory Memory: AuditoryECHOIC MEMORY

• Persistence of audition

• Capable of storing sequences of at least ~250 milliseconds and possibly more

• Masking sound

Short Term Memory• Information hold for 20-30 seconds after

which it is displaced by incoming information.

• Information encoded in STM is acoustic in nature (Speech, Sounds, Visual Images & Words).

• It is semantic in nature.Meaningful words may be stored easily as compared to nonsense syllables.

Short Term Memory• Serial-Position Effect:• Primacy Effect: Better recall of items at the

beginning of the list.• Recency Effect: Items encountered most recently are

remembered well.• STM can hold 5-9 chunks of information.

• Several items of information can be combined into one chunk.

• About 7 chunks can be retained.

• About 40 items can be combined into 7 chunks & can be held in STM.

Reason behind Primacy Effect

• Primacy effect remains during delayed recall because the first items get time to be put into LTM during the presentation of the list.

Visual MemoryICONIC MEMORY

• Holds information for up to 1-2 seconds.

• Visual persistence • ~ 100 milliseconds• Short-time visual trace

‘icon’• Features such as color,

shape and direction can be stored

• Brightness-masking• Pattern-masking

FLASHBULB MEMORY• Phenomenon of vivid

memories of important events

• Not necessarily accurate:what we typically recall in such situations is not what we experience but what we abstract from that experience (i.e. Eyewitness testimony, Recognition of faces).

Auditory MemorySHORT-TERM AUDITORY MEMORY

• There is evidence for two short-term auditory stores-a) one operating over a timescale of 150-350 milliseconds, andb) the other one lasting somewhere between 2 and 20 seconds.

• Modality effect: Advantage to spoken terms• Recency effect: Enhanced recall of the most

recently presented items

Auditory MemoryLONG-TERM AUDITORY MEMORY

• Memory for language: Stored in terms of meaning than sound.

• Memory for music: Both contour and pitch interval information are retained.

• Memory for voices: Voice recognition of a familiar person is reasonably good, but is poor for a stranger.

Rehearsal in STM(The process of keeping items of information in the

center of attention)Maintenance RehearsalMaintenance Rehearsal

• Repetition of information over & over again.

• Just going over & over again does not necessarily succeed transferring the information into LTM.

Elaborative RehearsalElaborative Rehearsal• Giving the material

organization & meaning as it is being rehearsed.

• It uses strategies of giving meaning & organizing materials so that it can fit in with the existing organized LTM.

Short Term Memory(Working Memory)

• 7+2 Chunks of memory can be kept in mind at a time and combined to make a decision.

• The size of the chunk varies greatly between experts and novices.

• Experts can combine many memory units to a whole (e.g. master chess players retain a series of moves)

Model of Working MemoryAllen D. Baddeley’s Model (1986)

(Little consensus at present)(Little consensus at present)

• Articulatory Loop (Verbal rehearsal takes place here)

• Visio-spatial sketchpad(Rehearsal of visually presented information)

• Central executive

• Control & decision making• Reasoning & Language comprehension• Transfer to LTM• Recency effects

(Short term buffer)• Articulatory processes• Recycling items for immediate recall• If imagery task is difficult executive’s resources are drained

• Visual Imagery Tasks• If imagery task is difficult executive’s resources are drained

fMRI: Working Memory

Fig. 1

Location of Working Memory

Fig. 2

Organization in Short Term Memory

In STM Chunks are organized in hierarchy.

• 5.6• 4.1• 2.0• .25

Long Term MemoryLong Term Memory• Intended to store information over a long time.

• It has unlimited capacity.

• Tulving (1972, 1983) ,a Canadian Psychologist, was the first to make distinction between episodic & semantic memory.

Long Term MemoryLong Term Memory

Specific Memory

Procedural Memory

Semantic Memory Episodic Memory

Declarative Memory

AutobiographicalMemory

Episodic memory

• Represents our memory of events and experiences in a serial form.

• Records an individual’s past experiences & episodes of one’s daily life.

Long Term MemoryLong Term Memory

Long Term MemoryLong Term Memory

Semantic Memory

• It is a structured record of facts, concepts and skills that we have acquired.

• Abstract knowledge & meaning of words, symbols, etc. are retained.

• It also contains ideas & rules for relating them.

Long Term MemoryLong Term Memory

Autobiographical Memory• Memories about event and experiences of

our own lives.

• The factors that affect other forms or memory also affect organization of autobiographical memory.

• Infantile Amnesia:Supposed inability to remember events from the first 2-3 year of life.

Semantic Memory• This memory system stores general

knowledge that is not associated with a specific place and time of acquisition.

Organization of semantic memoryOrganization of semantic memory• Semantic networks• Concepts• Prototypes• Exemplars

Episodic Memory• It is the memory for factual information that we

acquire at a specific time.

• Episodic memory is more susceptible to forgetting as compared to semantic memory.

• Organizations of information in LTM is subjective.

• Images of information are concrete & abstract.

• Concrete words are easier to learn than abstract words.

Episodic MemoryEpisodic Memory• Tip-of-the-tongue phenomenon supports the fact that

information in LTM is organized.

• Search in LTM is not random.

Factors affecting episodic memoryFactors affecting episodic memory:• Amount and spacing of practice• Type of processing• Levels of processing view• Retrieval cues• Context-dependant memory• State-dependant retrieval• Encoding specificity principle

New Developments in MEMORYMEMORY• Items can directly go into LTM (Anderson, 1995).

• Studies on patients gave two more concepts-

1. Implicit memory

2. Explicit memory

• Two more concepts-1. Declarative memory2. Procedural memory

• Declarative memory is memory of ‘what’, of facts & events.

• Procedural memory is memory of ‘how’, or the procedure.

• Procedural memory is usually implicit.• It is the knowledge of how to perform a task.• Older people show problems of Prospective

Memory (Fail to remember what they were going to do).

New Developments in MEMORYMEMORY

Procedural Memory• Memory systems that contain

information that we cannot readily express

• Procedural knowledge & skilled behaviors

• Skill acquisition• Automatic & controlled processing

Approximate duration

Iconic: 1-2 sec.Echoic: 4-5 sec.

20-30 seconds. Days, months, years or life time.

CapacityRelatively large. At least 16 items. Probably much more.

Relatively small. About 7 items or chunks.

Very large.Limit unknown.

Transference

Attention & recognition.Items attended to & recognized move to STM.

Rehearsal: Items appropriately rehearsed move to LTM. -

Type of information stored

Copy of input. Sounds, visual images, words & sentences.

Primarily meaningful sentences, life events & concepts, some images, semantic & episodic memory.

Information loss (Reason)

Decay of trace. Displacement of old information by incoming information.

Faulty organization, inappropriate retrieval strategy, interference.

Sensory STM LTM

Memory: Complex Cognitive Task

• There are fundamental differences between complex tasks and standard memory tasks.

• Working memory does not consist of a single general capacity, rather it consists of several subsystems for various types of tasks.

• Working memory in a specific skilled activity increases as one aspect of acquired skill.

• With practice and acquisition of memory skills, recall performance on a specific memory task can be improved by 100 to 1000%.

Memory in Children

• The effects of memory distortion and construction are more pronounced in children

• Children are more likely to commit errors in reality and source monitoring

Reconstructive MemoryBartlett (1932)

• A group of students were asked to read a story about North American Indians ‘The War of the Ghosts’.

• The story was reproduced after passing through several mouths.

• Almost all details related to American Indian culture were omitted & other were rationalized.

• Each narrator added something to the story from his own imagination.

• Many details of the story was leveled, making it simpler.• Narrators sharpened some other facts in the story &

exaggerated those aspects which they liked.• All these processes changed the story.

Reconstructive Memory: Indian Contribution• Durganand Sinha has done work on rumors in Indian setting.• J.P.Das & R. Kanungo’s study->Two group of students (Brahmins & Kayasthas) were given 4 lists of

adjectives.>List 1 had adjectives that described Brahmins in favourable terms: nice,

good looking, clean, etc.>List 2 had adjectives that described Brahmins in unfavourable terms:

rude, greedy, fat, etc.>List 3 had adjectives that described Kayasthas in favourable terms.>List 4 had adjectives that described Brahmins in unfavourable terms.

Brahmin students remembered adjectives favourable to them, but not favourable to the Kayasthas Similar was the case with the Kayasthas.Everyone remembered more unfavourable adjectives than favourableone.It suggests that, in general, people prefer to remember bad rather than good attributes.

Zeigarnik Effect (B. Zeigarnik)

• This Russian psychologist compared memory for tasks that were successfully completed & those which were not.

• In fact she interrupted the work & did not allow them to finish it.

• Interrupted tasks were remembered more frequently than those which were completed.

# This mismatches with our daily experience.

• Dutta & Kanungo gave a new interpretation to Zeigarnik effect.

• The intensity of emotion aroused by the completed or the interrupted task is the critical factor.

• Any activity that gives rise to strong emotion, be it pleasant or unpleasant, is remembered better than ordinary everyday action.

Zeigarnik Effect: Indian Contribution

Memory Construction• Recall of events that did not take place.

• Memory implantation

• These are not necessarily deliberate

• Suggestibility

• Source monitoring

• Illusion of out group homogeneity

Memory Distortion• The change in the content of recall (memory) as a

result of internal or external factors.

• Cognitive biases• Suggestive questioning• Factors affecting distortion• Schemas• Motivation• Source monitoring• Reality monitoring

Methods for Studying Memory

• Free recall & recognition• Sentence verification• Priming• Neuroimaging

Forgetting• One characteristic of human memory is

that humans forget.• Forgetting is a very useful attribute of the

human memory system.• Forgetting happens if learned messages

haven’t been transfered to the long-term memory.

• With hypnosis it is possible to retrieve things that have been forgotten.

Forgetting• During the process of forgetting important

features are filtered out and preserved, while irrelevant or predictable detail is either destroyed, or stored in such a way that it is not readily accessible in its original form.

• One obvious benefit of forgetting is the way in which it softens emotional pain or grief ”Time heals all wounds” - but it also represents a distortion of our recollection of the past.

Forgetting• Forgetting is the loss, decay,

inaccessibility of information in LTM • Interference• Retroactive: Newly learnt information prevents

retrieval of previously stored ones.

• Proactive• Retrieval inhibition

Repressed Memories• Elimination of threatening or extremely

painful memories from consciousness

• Very controversial

• Methods of eliciting false memories

Effect of Mood on Memory• Mood can serve as an internal

retrieval cues

• Mood-dependent memory

• Mood congruence effects

Towards Better MemoryTowards Better Memory

• Overlearning (leads to automatisation)

• Mnemonics (Rhymes & jingles)

• Method of loci

• Number-peg technique

Memory DisordersAmnesia

•• Retrograde: Retrograde: Memory loss for things learnt prior to the event initiating amnesia.

•• AnterogradeAnterograde: : Disruption of memory for experiences after the onset of amnesia.

Alzheimer’s disease• Gradual deterioration of memory functions• It appears that chemical and neurotransmitters

may be involved

Memory Location in the Brain: HippocampusHippocampus

• Transfers information from working memory to long term memory

• It helps the brain form memories by stimulating it to form new synapses. Neurons in the adult brain do not reproduce, they simply form new synapses.

• It appears that stimulation through the hippocampus causes new synapses to form & strengthen the synapses that already exist. This process is called long-term potentiation, LTP.

• This is the primary means by which learning, & consequently memory, takes place.

Memory Location in the Brain: HippocampusHippocampus

Memory Location in the Brain

•• Frontal lobesFrontal lobes: Working memory, encoding and retrieval of information from long term memory

•• Temporal lobesTemporal lobes: Semantic memory

Memory Location in the BrainMemory Location in the Brain• Some memories may be localized in certain specific areas of

the brain.

• Learning through classical conditioning is apparently stored in the cerebellum (McCormick et al., 1982).

• However, there is also evidence that in many cases memories are not stored in any single part of the brain.

• A single memory can be stored in numerous parts of the brain, so that removal of any one part can diminish but not erase the whole memory (Lashley, 1950) .

Memory Location in the Brain• Once these new connections have been formed &

long-term potentiation has taken place, the hippocampus is no longer necessary for the particular memory- the memory & all its connections to other information have become an integral part of the brain’s structure & will persist even if hippocampus is totally destroyed.(Zola-Morgan & Squire, 1990; Squire & Zola-Morgan, 1991)

Summary of Memory Function

Fig. 3

References1

2

3

www.nimh.nih.gov

www.nimh.nih.gov

Markowitsch, H.J. (1998). Cognitive Neuroscience of Memory. Neurocase, 4, 429-435.