FORGETTING What is forgetting? - PowerPoint Presentation

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FORGETTING

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What is forgetting?

Ebbinghaus

forgetting curve

Theories of forgetting

Decay Theory

Theory of Interference

Retrieval Theory

Theory of Inhibition

Motivated Forgetting

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Decay theory

Memories leave a trace in the brain.

Any physical and chemical changes in the brain results in a memory "trace."

Trace decay theory states that forgetting occurs as a result of the automatic decay or fading of memory trace, the events that happen between the formation of a memory and the recall of the memory have no impact on recall.

Hermann

Ebbinghaus

in 1885,

Ebbinghaus

forgetting curve

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Critical Evaluation

Not all memories follow the forgetting curve as there could be various other factors in play, such as noise and other environmental factors.

that it is difficult to demonstrate that time alone is responsible for declines in recall.

what happened during the time is crucial (

Jenkin

and

Dalenbach

, 924). A study by Minami and

Dalenbch

(1964) on cockroaches

Why some memories fade quickly while others linger.

Memories of shocking events like 9/11 attack, Boston bombing, etc are imprinted in our memory

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Theory of Interference

Proactive interference

 

Retroactive interference

Example

Evaluation

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Proactive Interference

 

Proactive interference

 (pro=forward) occurs when you cannot learn a new task because of an old task that had been learnt. 

where old memories disrupt new memories.

Learning a new phone number or locker combination

If you move into a new house

writing your old address

A native English speaker who is trying to learn French

Proactive interference is when older memories interfere with the retrieval of newer memories.

Proactive interference can sometimes make it more difficult to learn new things.

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Retroactive interference

 Retroactive interference (retro=backward) occurs when you forget a previously learnt task due to the learning of a new task. where new memories disrupt/interfere with the retrieval old memories.

This type of interference creates a backward effect, making it more difficult to recall things that have been previously learned

A musician might learn a new piece

A teacher learning the names of her new class of students

Recalling the information learned shortly than the material t learned earlier

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Critical Evaluation

Interference theory tells us little about the cognitive processes

Baddeley

(1990) states that the tasks given to subjects are too close to each other

andthat

does not happen in real life

There is no doubt that interference plays a role in forgetting, but how much forgetting can be attributed to interference remains unclear (Anderson, 2000).

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The Retrieval Failure Theory

Two of the basic reasons for this failure in memory retrieval are related to encoding failures and lack of retrieval cues.

Such information is said to be available (i.e. it is still stored) but not accessible (i.e. it cannot be retrieved). It cannot be accessed because the retrieval cues are not present

This is known as Cue-Dependent Theory of Forgetting.

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Retrieval cues can be:

External/contextual cues present in the environment, setting, situation

Internal/state dependent cues referring to the internal state of the individual

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External/contextual cues

Evidence indicates that retrieval is more likely when the context at encoding matches the context at retrieval.

An experiment by 

Tulving

and

Pearlstone

(1966) 

asked participants to learn lists of words belonging to different categories

Baddeley

(1975)

 experiment on deep-sea divers

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Internal/state dependent cues

Memory will be best when a person's physical or psychological state is similar at encoding and retrieval. 

Mood state at learning and at retrieval is the same is generally known as 

mood-state-dependent memory

.

A study by 

Goodwin et al. (1969)

 investigated the effect of alcohol on state-dependent retrieval. Recalling the hiding place is easy when drunk than when they were sober. 

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Theory of Inhibition

Forgetting of information due to the inhibition produced by the information we don’t try to remember

Brown(1968) recalling the names of 50 states of US.

Anderson and Spellman,1995

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Motivated Forgetting

Motivated forgetting arises from strong motive or desire to forget, usually because the experience is to disturbing or upsetting to remember.

The motivated forgetting theory was invented by Sigmund Freud.

The two types of motivated forgetting are repression (unconsciously) and suppression (consciously).

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Elimination of memories from the consciousness

What is too painful to remember, we simply choose to forget.

Featured mainly in dramatic trials about early childhood sexual abuse

Careful questioning, suggestive

techiniques

by trained therapists.

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Little scientific evidence to support the theory as most evidence is based on case studies

Therapists often suggest such memories in a subtle and unintentional way

Being influenced by media reports, person suffering from psychological problem conclude the cause as early sexual abuse and repressed memories

People often generate false memories for events that never happened(Goodman et al., 1996).

Study by Ceci,1995

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Amnesia

Amnesia is a form of memory loss stemming from illness, injury, drug abuse, or other causes. Some people with amnesia have difficulty forming new memories. Others can’t recall facts or past experiences. People with amnesia usually retain knowledge of their own identity, as well as motor skills.

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Types

Retrograde amnesia

Loss of memory of events that occurred prior to an amnesia-inducing event

Anterograde

amnesia

Inability to store information that occur after amnesia inducing event. When you have

anterograde

amnesia, you can’t form new memories.

Transient global amnesia

Infantile amnesia

Most people can’t remember the first three to five years of life.

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Causes of amnesia

Dementia

Anoxia

A depletion of oxygen levels can also affect your entire brain and lead to memory loss.

Damage to the hippocampus

Your hippocampus is a part of the brain and limbic system responsible for memory.

Head injuries

Traumatic head injuries, as well as stroke,

tumors

, and infections, can also cause damage to your brain.

Alcohol use

Short-term alcohol use can cause blackout.

Trauma or stress

Severe trauma or stress can also cause dissociative amnesia.

Electroconvulsive therapy

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Case study of S.P.

Case study of S.P.(Schnider,1994): An example of the dissociation between working memory and Long-term memory

S.P. , a 66 yr old suffered from stroke, affected medial temporal lobe of

hippocampus

Showed profound

anterograde

amnesia, could not enter information to long term memory

Could recognize his family members, retained the ability to acquire procedural memory

Hippocampus transforms the information from working memory to more permanent store LTM

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Case study of Clive Wearing

Case study of Clive Wearing: The temporal lobe and semantic memory

C.W., A musician caught infectious

encephalities

causing damage to frontal lobe and hippocampus

causing memory deficit which was recorded by wife Deborah

Deficits involved semantic memory

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Korsakoff’s

Syndrome

Consumption of large amount of alcohol for many years

Sensory motor problems, heart, liver,

gastrointenstinal

damage

Both

anterograde

and severe retrograde amnesia

Extensive damage to thalamus and hypothalamus

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Alzheimer’s Disease

Most tragic disorder during the closing decades of life

5% of the people over age 65 experience it

Statrts

with mild memory problem, gradually they become totally confused and unable to perform simple tasks like dressing or grooming themselves

Later they fail to recognize their family members

Suffers from wide range of memory impairment- WM,SM, EM, memory for skills, autobiographical memory all get disturbed

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Cause

The brain contains tangles of

amyloid

beta protein which is not found in normal brain(low concentration

This damages the neurons that projects from the

neclei

in the basal forebrain to hippocampus and cerebral cortex

These neurons transmit information by means of the neurotransmitter acetylcholine a substance that plays key role in memory

A patients contains lower than normal amounts of acetylcholine

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THANK YOU