Memory is the ability to encode, store, and recall past experiences. There are three main types of memory: sensory memory (less than 1 second), short-term memory (less than 1 minute), and long-term memory (lifetime). Long-term memory includes both implicit memory (procedural memory like skills) and explicit memory (facts and autobiographical events), which can be either episodic (personal experiences) or semantic (general knowledge). Memory is distributed across the brain and involves encoding, storing, and retrieving information over time. It is influenced by many factors and is not perfectly accurate, as memories can be distorted or modified over time.

1. MEMORY INTRODUCTION
is an organism's abilityto store, retain, and recall
informationand experiences
is our abilityto encode, store, retain and subsequently
recall information and past experiences in the human
brain.
Encoding: a process of making mental representation of
information.It can also mean transferring from short term to
long term. is the more or less passive process of retaining
informationin the brain, whether in the sensory memory, the
short-term memory or the more permanent long-term
memory.
Storing:Process of placing encoded informationinto
relativelypermanent storage for later recall.
Remembering:the process of retrieving what has been
stored in short term or long term memory.
The power or process of reproducing or recalling what has
been learnedand retained esp. through associative
mechanisms
 The store of things learned and retained from an
organism’s activity or experience as indicated by
modification of structure or behavior or by recall
or rec behaviour.In general terms one can define

2. memory as the use of past experience to influence
or affect human
WHERE MEMORY COMES FROM
Memory is not located on one particular part
of the brain but instead there is a brain wide
process in which different parts of the brain
work in conjunction with one
another(distributing process).
 For example: when riding a bicycle, the whole
process is reconstructed by the brain in different
areas.
 The memory of how to operate the bike comes
from one area, the memory of the street paths
comes from another area, the memory of bike
safety rules in another and the nervous feeling
when almost falling or being hit comes from
another part of the brain.

3. DISTRIBUTIVE PROCESS DIAGRAM
TYPES OF MEMORY
There are three main types of memory
1.Sensory memory
2.Long term memory
3.Short term memory
 Unlike the other two types, long type memory is
extensive as it lasts a lifetime and thus has further sub
divisions as can be seen in the diagram below

4. Types of memory diagram
(a)SENSORY MEMORY (<1sec)
 Sensory memories the Shortest term element of
memory. In order for anything to enter our memory, it
must be picked up by our senses(taste, touch, sight,
hearing and smell).
 Sensory memory makes use of the five senses in order
to be developed.
 For example, the ability to look at something and
remember what it looked like with just a second of
observation is an example of sensory memory.

5.  The ability to look at an item for a second and then
remember what it looked like.
 -It is processed approximately 200-500 milliseconds
after an item is perceived.
(b)SHORT TERM MEMORY
(<1min)
 Also called working memory. It is everything you are
thinking of at the current moment. Takes less than one
minute to process.
 It is the informationwe hang on to while doing another
process and it tends to disappearreally fast unless we
make an effort to rememberit.
 For example, when reading a sentence, you place the
beginning of the sentence in mind so as to understand
the rest of the sentence acts as a kind of “scratch-pad”
for temporary recall of the information which is being
processed at any point in time, and has been referred
to as "the brain'sPost-it note".
(C)LONG TERM MEMORY (life- time)
This is a process of storing unlimited amounts of
information over long period of time.

6. Although there is the element of forgetting, long
term memorydecays very little and we are thus able
to recall most of it.
Short term memories can become long term
memories through the process of consolidation
which involves rehearsal and meaningful
association.
Unlike short-term memory (which relies mostly on
an acoustic, and to a lesser extent a visual, code for
storing information), long-term memoryencodes
information for storage semantically (i.e. based on
meaning and association).

7. Long term memory location
Characteristics of long term memory
 It has an unlimited capacity and it is
relatively permanent.
 Chances of retrieval are dependent
on encoding process.
 Its accuracy may be distorted over
time
TYPES OF LONG TERM MEMORY

8. a) IMPLICIT MEMORY(procedural)
 Implicit memory is memory that can
be unconsciously recalled. This is also
known as procedural memory. It is a
memory of skills and how to do
things, particularly movement of
body parts and use of objects or
machines.
 This is memory acquired through
repetition and practise and is
composed of automatic sensorimeter
behaviours that are so deeply
embedded that we are no longer
aware of them. An example is when
you teach a child to write over and
over again, eventually it becomes
embedded in him until he is able to do
it simply without thinking so much
about it. Other examples include
riding a bike, tying a shoe-lace,
playing the guitar etc.
This type of long-term memory allowspeople to carry
out ordinary motor actionsmore or less automatically.Thisis

9. aided by previousperformances of the task without explicit
or conscious awareness of the previousexperiences, like you
do not remember how you learnt how to hold a spoon or
how to tie your shoe lace, yet now you can do it more
unconsciously.
Implicit memory is stored and encoded by the
cerebellum, putamen, caudate nucleus and the motor
cortex- all of which are involvedin motor control
Factors Affecting Implicit Memory
 Stroke
 Depression and stress
 Drug abuse
 Lack of sleep
 Nutritional deficiency
 Head injury
 Medications
b)EXPLICIT(declarative)
 Declarative memory is a type of long term memory
and it is also known as explicit memory.

10.  It is in this memory where we store memories of
fact.
 Your abilityto recall addresses, locationsof parking
garages, intersection names, phone numbers, and
an experience that you had at a restaurant are all a
part of declarative memory. For example: let's say
that you know that your favourite restaurant is only
open until 6 PM on Sundays. The time that the
restaurant closes is stored as a declarative
memory. We can consciously recall declarative
memory.
Factors Affecting Declarative Memory.
STRESS
 Through experimentation method,
scholars have been able to detect that
those who are undergoing stress tend
to affect their declarative memory
more than those who are not
undergoing stress.
1.EPISODIC MEMORY
 Episodic memory represents our memory
of experiences and specific events in time, from

11. which we can reconstructthe actual events that
took place at any given point in our lives
 Episodic memory is what enables one to give an
account of an event which happened and will
tend to be different from someone else's.
 EXAMPLES OF EPISODIC MEMORY
 First day at a new job.
 First movie you watched with your
wife.
 The first time you travelled by plane.
 Your wedding day.
 Your first kiss.
2.SEMANTIC MEMORY
 Semantic memory includes things that are common
knowledge, such as the names of colors, the sounds of
letters, the capitals of countries and basic facts
acquired over a life time.
 Semantic memory is the recollection of facts gathered
from the time we are young
Examples of semantic memory
Knowing that grass is green.

12. Knowing how to use scissors.
Understandinghow to put words together to form a
sentence.
Knowing how to use a phone.
Recognizing the names of colours
RETROSPECTIVE & PROSPECTIVE
MEMORY
An important alternative classification of long-term
memoryused by some researchers is based on the
temporal direction of the memories.
Retrospective memoryis where the content to be
remembered (people, words, events, etc) is in the past,
i.e. the recollection of past episodes. It includes
semantic, episodic and autobiographical memory, and
declarative memory in general, although it can be
either explicit or implicit.
Prospective memoryis where the content is to be
remembered in the future, and may be defined as
“rememberingto remember”or rememberingto
perform an intended action. It may be either event-
based or time-based, often triggered by a cue, such as
going to the doctor (action) at 4pm (cue), or

13. rememberingto post a letter (action) after seeing a
mailbox (cue).
Clearly, though, retrospective and prospective memory
are not entirely independent entities, and certain
aspects of retrospective memoryare usually required
for prospective memory. Thus, there have been case
studies where an impaired retrospective memoryhas
caused a definite impact on prospective memory.
However, there have also been studies where patients
with an impaired prospective memoryhad an intact
retrospective memory, suggesting that to some extent
the two types of memoryinvolve separate processes.
GENERAL FACTORS AFFECTING MEMORY.
a. Ability to retain:
This depends upon good memorytraces left in the
brain by past experiences.
b. Good health:
A person with good health can retain the learnt
material better than a person with poor health.
c. Age of the learner:
Youngsters can remember better than the aged.
d. Maturity:

14. Very young children cannot retain and remember
complex material.
e. Will to remember:
Willingness to remember helps for better retention.
f. Intelligence:
More intelligent person will have better memorythan
a dull person,
g. Interest:
If a person has more interest, he will learn and retain
better.
h. Over learning:
Experiments have proved that over learning will lead
to better memory.
i. Speed of learning:
Quicker learning leads to better retention,
j. Meaningfulness of the material:
Meaningful materials remain in our memoryfor longer
period than for nonsense material,
k. Sleep or rest:
Sleep or rest immediatelyafter learning strengthens
connections in the brain and helps for clear memory.
How Accurate is Memory
 Most people think that a memory is like a
nonfiction book or movie. Scientists have found
that human memory changes constantly. Memories

15. lose detail & become distorted as time passes.They
are shaped and reshaped by people’s beliefs,
expectations and views of themselves. People
modify their memoriesto include newly learned
information-even if the facts are wrong.

 Painful memories lost and found, are harder to find
the truth especially when it comes to victims of
child abuse. Between 8 and 38% of women in
surveys thought they had suffered some kind of
sexual abuse as a child. So

 Memories are distributed throughout our brains so
if one part of an experience is lost, another part of
it remains, example: If a memoryof someone's
name is lost, the memoryof their face is not.
Memory Glossary
 Flashbulb Memories- are Vivid, detailed
memories of events associated with strong
emotions.
 Eidetic Memory- The ability to remember
information and its surroundingsin great detail:
sometimes called photographic memory.

16.  Episodic Memory- Memory for events in a
person’s past: a form of explicit memory
 Implicit Memory- The system of memoriesthat
do not enter conscious awareness, including
memories for learned skills, habits, and
conditioning
 Long-Term Memory- Explicit memory that lasts
for more than a few minutes
 Perceptual Memory- A form of memoryin
which sense perceptions are recorded in the
brain for a few seconds
 Anterograde Amnesia- the inability to form new
long term memories
 Acetylcholine-a neurotransmitterused by some
nerve cells, including those destroyed by
Alzheimer’sdisease
 Korsakoff’sSyndrome- A kind of amnesia that
usually affects alcoholics who eat a diet lacking
vitamin B
 Post-Traumatic Stress Disorder (PTSD)- A
disorder sometimes sufferedby people who
have sufferedterrifying experiences; it can
include nightmares and vivid memory
“flashbacks”.

17. Some causes of Memory Loss
Poor Health especially lack of Vitamin B
Severe Stress & unhappiness can interfere with
Memory
Alcohol slows down the nervous system and can block
storage of new memories
Traumatic experiences, Head injury, Addiction