THEORIES OF FORGETTING

1. FORGETTING
BY- ISHITA

2. Why do we
forget?
There are two simple answers to this
question.
1. Encoding failure
2. Trace decay
3. Interference
4. Displacement
5. Motivated forgetting

3. •Forgetting information from short term
memory (STM) can be explained using the
theories of trace decay and displacement.
•Forgetting from long term memory (LTM) can be
explained using the theories of interference,
retrieval failure and lack of consolidation.

4. TRACE
DECAY
• This explanation of forgetting in short term
memory assumes that memories leave a
trace in the brain. A trace is some form of
physical and/or chemical change in the
nervous system.
• Trace decay theory states that forgetting
occurs as a result of the automatic decay
or fading of the memory trace. It focuses
on time and the limited duration of short
term memory.
• This theory suggests short term memory
can only hold information between 15
and 30 seconds unless it is
rehearsed. After this time the information
fades away.

5. • According to the trace decay theory of forgetting, the events
between learning and recall have no affect whatsoever on
recall. It is the length of time the information has to be
retained that is important. The longer the time, the more the
memory trace decays and as a consequence more information
is forgotten.
• Clearly, in any real-life situation, the time between learning
something and recalling it will be filled with all kinds of
different events. This makes it very difficult to be sure that any
forgetting which takes place is the result of decay rather than a
consequence of the intervening events.

6. ENCODING
FAILURE
• Many memory failures result not from
forgetting information that we once
knew, but from failing to encode the
information into long-term memory in
the first place.
• Even when we notice information we
may fail to encode it deeply because
we turn our attention to something
else.

7. • In an experiment involving 324 adults, psychologist Brad J. Bushman and Angelica M.
Bonacci randomly assigned the participants to watch a violent, sexually explicit, or
neutral television program. Each program contained nine ads for products with broad
market appeal, such as soft drinks, cereal and laundry detergent. Immediately after
viewing the TV program, the participants were given a surprise test in which they tried to
recall the brand names in the commercial messages. The next day the participants were
contacted by telephone and were again asked to recall the advertised brands.
• Results show those participants who saw the ads during a neutral program (no sexual or
violent content) had better memory of the products advertised than did participants who
saw the ads during a sexual or violent program, both immediately after exposure and 24
hours later. One of the reasons for this is encoding failure: all the viewers clearly saw the
ads but those watching sexually explicit and violent programs likely were the most
preoccupied with thoughts about the content of the shows.

8. DISPLACEMENT
• Displacement theory provides a very simple
explanation of forgetting. Because of its limited
capacity, suggested by Miller to be 7+/- 2 items,
STM can only hold small amounts of information.
• When STM is 'full', new information displaces or
'pushes out’ old information and takes its
place. The old information which is displaced is
forgotten in STM.
• It was also assumed that the information that had
been in the short-term store for the longest was
the first to be displaced by new information,
similar to the way in which boxes might fall off
the end of a conveyor belt - as new boxes are put
on one end, the boxes which have been on the
conveyor belt the longest drop off the end.

9. • Support for the view that displacement was
responsible for the loss of information from short-
term memory came from studies using the 'free-
recall' method.
• A typical study would use the following procedure:
participants listen to a list of words read out at a
steady rate, usually two seconds per word; they are
then asked to recall as many of words as possible.
They are free to recall the words in any order, hence
the term 'free recall’.

10. The findings from studies
using free recall are reliable
and they produce similar
results on each occasion. If
you take each item in the
list and calculate the
probability of participants
recalling it (by averaging
recall of the word over all
participants) and plot this
against the item's position
in the list, it results in the
serial position curve.

11. • Good recall of items at the beginning of the
list is referred to as the primacy effect and
good recall of items at the end of the list are
referred to as the recency effect. The
displacement theory of forgetting from
short-term memory can explain the recency
effect quite easily. The last few words that
were presented in the list have not yet been
displaced from short-term memory and so
are available for recall.
• The primacy effect can be explained using
Atkinson & Shiffrin's (1968) multi-store
model which proposes that information is
transferred into long-term memory by
means of rehearsal.

12. INTERFERENCE
• It was assumed that memory can be disrupted or
interfered with by what we have previously
learned or by what we will learn in the
future. This idea suggests that information in
long term memory may become confused or
combined with other information during
encoding thus distorting or disrupting memories.
• Interference theory states that forgetting occurs
because memories interfere with and disrupt one
another, in other words forgetting occurs because
of interference from other memories (Baddeley,
1999).

13. There are two ways in which interference
can cause forgetting:
1. Proactive interference (pro=forward)
occurs when you cannot learn a new task
because of an old task that had been
learnt. When what we already know
interferes with what we are currently
learning – where old memories disrupt
new memories.
2. Retroactive
interference (retro=backward) occurs
when you forget a previously learnt task
due to the learning of a new task. In
other words, later learning interferes
with earlier learning - where new
memories disrupt old memories.

14. • Proactive and retroactive Interference is more likely to occur where the
memories are similar, for example: confusing old and new telephone
numbers. Chandler (1989) stated that students who study similar subjects at
the same time often experience interference.
• Previous learning can sometimes interfere with new learning (e.g. difficulties
we have with foreign currency when travelling abroad). Also new learning can
sometimes cause confusion with previous learning. (Starting French may affect
our memory of previously learned Spanish vocabulary).
• In the short term memory, interference can occur in the form of distractions so
that we don’t get the chance to process the information properly in the first
place. (e.g. someone using a loud drill just outside the door of the classroom.)

15. KEY
STUDY-
POSTMAN
Aim: To investigate how retroactive interference affects
learning. In other words, to investigate whether information you
have recently received interferes with the ability to recall
something you learned earlier.
Method: A lab experiment was used. Participants were split into
two groups. Both groups had to remember a list of paired words
– e.g. cat - tree, jelly - moss, book - tractor. The experimental
group also had to learn another list of words where the second
paired word was different – e.g. cat – glass, jelly- time, book –
revolver. The control group were not given the second list. All
participants were asked to recall the words on the first list.
Results: The recall of the control group was more accurate than
that of the experimental group.
Conclusion: This suggests that learning items in the second list
interfered with participants’ ability to recall the list. This is an
example of retroactive interference.

16. MOTIVATED
FORGETTING
• Motivated forgetting is a theorized psychological
behaviour in which people may forget unwanted
memories, either consciously or unconsciously.
Motivated forgetting is also defined as a form of
conscious coping strategy.
• For instance, a person might direct his/her mind
towards unrelated topics when something reminds
them of unpleasant events. This could lead to
forgetting of a memory without having any
intention to forget, making the action of
forgetting motivated.

17. Suppression - forgetting ones thoughts and memories consciously.
For example 'A woman being raped by a stranger. After a few years, someone asks
the women if she had had such an experience. She replied 'No' even though there
was. She is suppressing her bad thought unconsciously.
For example 'When you ask someone who failed their major exam, how they went,
if they tell you they can't remember then they are consciously suppressing their
upsetting memory.
Repression - The concept of forgetting ones feeling unconsciously.
For example - When asked at what age we talked and walked, we reply 'I don't
know'. This is because we were still young.
For example - When a young girl was physically abused, but during her later
years of life she can not remember. However she has difficulty trusting and
relating to others, therefore there is difficulty forming relationships.
Suppression is consciously forgetting an idea, an incident, an experience while
repression is unconsciously forgetting an idea, an incident or an experience.

18. FORGETTING TO DO THINGS:
PROSPECTIVE MEMORY
• Prospective memory is a memory difficulty associated with forgetting to do things in
the future, such as remembering that a report is due in 2 weeks.
• Failures of prospective memory typically occur when we form an intention to do
something later, become engaged with various other tasks, and lose focus on the
thing we originally intended to do. Despite the name, prospective memory
actually depends on several cognitive processes, including planning, attention,
and task management. Common in everyday life, these memory lapses are mostly
annoying, but can have tragic consequences.

19. • Many examples of prospective memory involve intending to do something
at a particular time, such as going to a doctor’s appointment, or on a
particular occasion, such as congratulating a friend the next time you see
her. However, much of what we intend to do in our everyday lives, whether
at home or at work, involves habitual tasks repeated over time. And when
it comes to these kinds of habitual tasks, our intentions may not be
explicit. We usually don’t, for example, form an explicit intention to insert
the key in the ignition every time we drive a car—the intention is implicit
in our habitual routine of driving.
• For all the negative attention that multitasking has received in recent
years, it is perhaps no surprise that multitasking is also a major cause of
prospective memory failures. We seem to have adapted fairly well to
juggling several tasks simultaneously. But research shows that when a
problem arises with whatever task we’re currently focused on, we become
vulnerable to cognitive tunneling, forgetting to switch our attention back
to the other tasks at hand.

20. RETRIEVAL FAILURE
Retrieval failure is where the information is in long term
memory but cannot be accessed. 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 absence of retrieval
cues.
When we store a new memory we also store information about
the situation and these are known as retrieval cues.
When we come into the same situation again, these retrieval
cues can trigger the memory of the situation.
Retrieval cues can be:
oExternal / Context - in the environment, e.g. smell, place
etc.
oInternal / State- inside of us, e.g. physical, emotional,
mood, drunk etc.

21. • Tulving (1974) argued that information would be
more readily retrieved if the cues present when the
information was encoded were also present when
its retrieval is required. For example, if you
proposed to your partner when a certain song was
playing on the radio, you will be more likely to
remember the details of the proposal when you
hear the same song again. The song is a retrieval
cue - it was present when the information was
encoded and retrieved.
• Tulving suggested that information about the
physical surroundings (external context) and about
the physical or psychological state of the learner
(internal context) is stored at the same time as
information is learned. Reinstating the state or
context makes recall easier by providing relevant
information, while retrieval failure occurs when
appropriate cues are not present. For example,
when we are in a different context (i.e. situation) or
state.

22. EXTERNAL
CUES
• Retrieval cues may be based on
context-the setting or situation in
which information is encoded and
retrieved. Examples include a particular
room, driving along a motorway, a
certain group of people, a rainy day
and so on.

23. INTERNAL
CUES
• The basic idea behind state-dependent
retrieval is that memory will be best
when a person's physical or
psychological state is similar at
encoding and retrieval.
• For example, if someone tells you a
joke on Saturday night after a few
drinks, you'll be more likely to
remember it when you're in a similar
state - at a later date after a few more
drinks. Stone cold sober on Monday
morning, you'll be more likely to forget
the joke.

24. A number of experiments have indicated the importance of context-based cues for retrieval.
An experiment conducted by Tulving and Pearlstone (1966) asked participants to learn lists of
words belonging to different categories, for example names of animals, clothing and sports.
Participants were then asked to recall the words. Those who were given the category names
recalled substantially more words than those who were not. The categories provided a
context, and naming the categories provided retrieval cues. Tulving and Pearlstone argued that
cue-dependent forgetting explains the difference between the two groups of participants.
Those who recalled fewer words lacked appropriate retrieval cues.
TULVING

25. • An interesting experiment conducted by Baddeley (1975) indicates the
importance of setting for retrieval. Baddeley (1975) asked deep-sea divers
to memorize a list of words. One group did this on the beach and the
other group underwater. When they were asked to remember the words
half of the beach learners remained on the beach, the rest had to recall
underwater. Half of the underwater group remained there and the others
had to recall on the beach. The results show that those who had recalled
in the same environment (i.e. context) which that had learned recalled
40% more words than those recalling in a different environment. This
suggests that the retrieval of information is improved if it occurs in the
context in which it was learned.

26. AMNESIAThe term amnesia refers to memory loss due to special conditions, such
as brain injury, illness, psychological trauma. It is the general term for a
condition in which memory is disturbed or lost, to a greater extent
than simple everyday forgetting or absent-mindedness. It may result
either from organic or neurological causes or
from functional or psychogenic causes (psychological factors, such as
mental disorder, post-traumatic stress or psychological defence
mechanisms).
Amnesia can take several forms- retrograde amnesia, anterograde
amnesia, post traumatic amnesia, dissociative amnesia, infantile
amnesia, Korsakoff’s syndrome and many others.

27. •
Anterograde amnesia is the inability to create new memories due
to brain damage, while long-term memories from before the event
remain intact. It cannot be treated with pharmacological methods
due to neuronal loss. However, treatment exists in educating
patients to define their daily routines and after several steps they
begin to benefit from their procedural memory.
• Retrograde amnesia is inability to recall memories before onset of
amnesia. One may be able to encode new memories after the
incident. It is usually caused by head trauma or brain damage to
parts of the brain besides the hippocampus. The hippocampus is
responsible for encoding new memory. Episodic memory is more
likely to be affected than semantic memory. People suffering from
retrograde amnesia are more likely to remember general
rather than specifics. Recent memories are less likely to be
recovered, but older memories will be easier to recall due to
strengthening over time. It is usually temporary and can be treated
by exposing them to memories from the loss.[

28. Karsakoff’s Syndrome is an amnestic disorder caused by thiamine (vitamin B1) deficiency
associated with prolonged ingestion of alcohol. There is a similar condition seen in non-
alcoholic Korsakoff.
Dissociative amnesia results from a psychological cause as opposed to direct damage to the
brain caused by head injury, physical trauma or disease, which is known as organic amnesia.
Post-traumatic amnesia is generally due to a head injury. Traumatic amnesia is often transient,
but may be permanent or either anterograde, retrograde, or mixed type. The extent of the
period covered by the amnesia is related to the degree of injury and may give an indication of
the prognosis for recovery of other functions. Mild trauma, such as a car accident that results
no more than mild whiplash, might cause the occupant of a car to have no memory of the
moments just before the accident due to a brief interruption in the short/long-term memory
transfer mechanism. The sufferer may also lose knowledge of who people are. Having longer
periods of amnesia or consciousness after an injury may be an indication that recovery from
remaining concussion symptoms will take much longer.[

29. INFANTILE
AMNESIA
Infantile amnesia is the label given to the common inability
of adults to remember the earliest years of their
childhood, typically from birth until around four years old.
Various hypotheses have been put forward,
including Sigmund Freud’s theory of the repression of
memories of traumatic events that (according to Freud)
necessarily occur in the psychosexual development of
every child; the lack of neurological development of the
infant brain necessary for the creation of long-term
memories, particularly the hippocampus and prefrontal
cortex which do not develop into mature structures until
the age of three or four years; the incomplete
development of language in infants so that
autobiographical memories are not encoded in a manner
that their language-based adult selves can interpret
correctly; etc.

30. ALZHEIMER’S
DISEASE
Alzheimer's disease is a progressive disorder that causes
brain cells to waste away (degenerate) and die. It is the
most common cause of dementia — a continuous decline
in thinking, behavioural and social skills that disrupts a
person's ability to function independently.
The early signs of the disease may be forgetting recent
events or conversations. As the disease progresses, a
person with Alzheimer's disease will develop severe
memory impairment and lose the ability to carry out
everyday tasks.
There is no treatment that cures Alzheimer's disease or
alters the disease process in the brain. In advanced stages
of the disease, complications from severe loss of brain
function — such as dehydration, malnutrition or infection
— result in death.

31. DEMENTIA
Dementia is an overall term for diseases and
conditions characterized by a decline in memory,
language, problem-solving and other thinking skills
that affect a person's ability to perform everyday
activities. Memory loss is an example. Alzheimer's is
the most common cause of dementia.
Dementia is not a single disease; it’s an overall term
— like heart disease — that covers a wide range of
specific medical conditions. Disorders grouped
under the general term “dementia” are caused by
abnormal brain changes. These changes trigger a
decline in thinking skills, also known as cognitive
abilities, severe enough to impair daily life and
independent function.

32. TIP OF THE TONGUE
PHENOMENON
In psycholinguistics, the tip-of-the-
tongue phenomenon is that
feeling that a name, word, or
phrase—though momentarily
unrecallable—is known and will
soon be recalled.
"What's the name of that stuff I
wanted to tell your mother to
use?"
"Wait a second. I know."
"It's on the tip of my tongue," she
said.
"Wait a second. I know."
"You know the stuff I mean."
"The sleep stuff or the
indigestion?"
"It's on the tip of my tongue."
"Wait a second. Wait a second. I
know."

33. • The tip-of-the-tongue phenomenon (henceforth, TOT) straddles the line
between what we think of as memory and what we think of as language,
two closely related cognitive domains that have been studied somewhat
independently of each other. Consider the following example. "Political
pundits used to make fun of former President George H. Bush because of
his frequent word-finding failures. Despite his obvious depth of knowledge
and expertise, his speeches were sometimes characterized by pauses
suggesting a failure to recall a known word. His deficit was usually
attributed to absent-mindedness, rather than a lack of clear thinking. In
other words, it was dismissed as a language-production failure, not a
more consequential memory failure. His son, President George W. Bush,
suffers from a similar affliction. However, the son's speech errors (e.g.,
'Kosovarians,' 'subliminable') are often interpreted as a lack of knowledge,
and therefore, a learning deficit; a more consequential one for a president.

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