A REVIEW ON LEARNING AND MEMORY

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Gupta et al Journal of Drug Delivery & Therapeutics. 2018; 8(2):153-157
ISSN: 2250-1177 [153] CODEN (USA): JDDTAO
Available online on 15.03.2018 at http://jddtonline.info
Journal of Drug Delivery and Therapeutics
Open Access to Pharmaceutical and Medical Research
© 2011-18, publisher and licensee JDDT, This is an Open Access article which permits unrestricted non-
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Open Access Review Article
A REVIEW ON LEARNING AND MEMORY
Gupta Avneet*, Singh Manish Pal and Sisodia S. Siddhraj
Department of Pharmacology, Bhupal Nobles’ College of Pharmacy, Bhupal Nobles’ University, Udaipur, Rajasthan, India
ABSTRACT
Learning is defined as the acquisition of information and skills and subsequent retention of the information is called memory.
Dementia is one of the ages related mental problems and characteristic symptom of various neurodegenerative disorders including
Alzheimer’s disease which is age related. It is a progressive and neurodegenerative disorder. The analysis of the anatomical and
physical bases of learning and memory is one of the great successes of modern neuroscience. The action of drugs on memory is
more or less specific and serious depending on the memory system affected. So the present study is therefore focused on the various
types of learning and memory.
Key Words: Learning, Memory, Dementia.
Article Info: Received 09 Jan, 2018; Review Completed 23 Feb, 2018; Accepted 25 Feb, 2018; Available online 15 March, 2018
Cite this article as:
Gupta A, Singh MP, Sisodia SS, A review on learning and memory, Journal of Drug Delivery and Therapeutics.
2018; 8(2):153-157
DOI: http://dx.doi.org/10.22270/jddt.v8i2.1671
*Address for Correspondence
Avneet Gupta, Research Scholar, Department of Pharmacology, Bhupal Nobles’ College of Pharmacy, Bhupal Nobles’ University,
Udaipur, Rajasthan, India.
INTRODUCTION
The analysis of the anatomical and physical bases of
learning and memory is one of the great successes of
modern neuroscience1. In this we will discuss different
issues that are central to learning and memory. First
what are the different types of learning and memory?
Second, where in the brain is memory located and
learning cycle. Third, different types of memory
theories. Fourth, how memory work and disorders of
memory. Learning is the process by which we acquire
knowledge about the world. While this definition is
erudite, it doesn’t help us much in knowing what to
study2. Another definition Learning refers to a more or
less permanent change in behavior which occurs as a
result of practice, is a little better3. Learning and memory
are vital attributes of human intelligence. These
processes underlie the very nature of our self-
awareness4. Learning is a change in behavior or in
potential behavior that occurs as results of experience.
The three major types of learning described
by behavioral psychology are classical conditioning,
operant conditioning and observational learning5. When
people identify objects in the environment (e.g. knowing
that a thing is a plant or animal) or when they give the
answer to a factual question, they draw upon stores of
general knowledge about the world accumulated over
time. This type of memory is often referred as a sematic
memory6. The action of drugs on memory is more or less
specific and serious depending on the memory system
affected. Thus, analysis of the type of memory alteration
can be used to incriminate more a particular drug during
polymedication. Dementia is one of the ages related
mental problems and characteristic symptom of various
neurodegenerative disorders including Alzheimer’s
disease which is age related. It is a progressive and
neurodegenerative disorder which primarily affects the
elderly population and it is considered to be responsible
for 60% of all dementia in people who are aged 65 or
more. It is debilitating in nature and due to which an
enormous social and economic worry is placed on our
society. Currently there is no proper cure for the disorder
and much of the treatments available have been able to
only delay the progression of the disease or provide

Gupta et al Journal of Drug Delivery & Therapeutics. 2018; 8(2):153-157
ISSN: 2250-1177 [154] CODEN (USA): JDDTAO
symptomatic relief for a short time period. Therefore
there is a need for a different approach to the treatment
of these diseases7. The present study is therefore the
focused on discussing the various types of learning and
memory.
TYPES OF LEARNING
Associative Learning
In associative learning, we “learn” that two stimuli are
associated with each other or that a response is
associated with a given event or have a given
consequence. Perhaps important in clinical
considerations, a person can also learn that an outcome
is not associated with a response. So a person may learn
that what happens to him is not related to what he
does8. It is the process by which someone learns an
association between two stimuli or behavior and a
stimulus Associative learning occurs when you learn
something based on a new stimulus9.
Classical Conditioning
Classical conditioning is well demonstrated by Pavlov’s
famous experiment in which he presented meat powder
to a dog, causing it to salivate. He repeated the
presentation, and each time the dog salivated. If he
repeatedly rang a bell just before presenting the meat
powder (they were paired), the animal came to associate
the bell with the presentation of the meat powder, and it
would begin to salivate when the bell was rung. In fact,
for a while it would salivate if the bell was rung but no
meat powder was presented (they were unpaired). After
a while, the bell stopped predicting the presentation of
meat powder for the dog and it ceased salivating when it
was rung. This process is called extinction10.
It should be noted that for classical conditioning to occur
the ringing of the bell must precede the presentation of
the meat powder often by a certain critical interval of
time (of the order of 0.5 sec). One way to look at
classical conditioning is to think of the bell as becoming
a signal that the meat powder is about to be presented. In
Pavlov’s paradigm, the meat powder normally elicits
salivation without experimenter intervention (it is innate
or perhaps previously strongly learned) and it is called
the unconditioned stimulus (US). The response is called
the unconditioned response (UR). The bell comes to
elicit salivation only after it is repeatedly paired with
meat powder; so it’s called the conditioned stimulus
(CS). The response to it (again salivation) is called the
conditioned response (CR). The UR and the CR are
usually similar but often not identical in type or
strength11.
Figure 1: Classical Conditioning: Learning through Association.
Operant Conditioning
Operant conditioning from psychologist B.F. Skinner's
experiments, involves the use of a schedule of
reinforcements or rewards and punishments until the
behavior is learned. For instance, if the dog were to hear
the bell and step on a lever, it would receive the dog
biscuit the reward. Alternatively, if the dog were to step
on the lever when the bell doesn't ring and receive a

Gupta et al Journal of Drug Delivery & Therapeutics. 2018; 8(2):153-157
ISSN: 2250-1177 [155] CODEN (USA): JDDTAO
shock - a positive punishment that would shape behavior
in the opposite direction. A negative punishment, by
contrast, would be to take away something, such as a
biscuit, if the dog barks. If a child completes the home
work she is praised (rewarded) by the parents and the
child learns to perform the task. If the child breaks a
plate, he/she is scolded (punished) and she will learn not
to repeat the behavior. This is called Operant
Conditioning or instrumental conditioning12. In other
words, we learn to perform behaviors that produce
positive outcomes and avoid behaviors that yield
negative outcomes. We may define operant conditioning
as a process through which organisms learn to repeat
behaviors that produce positive outcomes or avoid or
escape from the negative outcomes. B.F. Skinner is
considered as the most influential psychologist
advocating the role of operant conditioning in learning.
He developed an experimental chamber (called Skinner
box) to study learning process in rats. The chamber
included a lever attached to the front wall. Pressing the
lever is the response to be learned. The hungry rat is
placed in the chamber and it starts doing random activity
in it. After some time, the rat accidentally presses the
lever and a pellet of food drops automatically in the
plate and the rat eats it. After eating the pallet the rat
again starts activity in the chamber. After some activity
it again presses the lever and gets pellet (a reward).
Gradually the random activity changes to more specific
activity around the lever. Finally, the rat learns that
pressing the lever results in dropping of the food, a
satisfying outcome. In other words the pressing of lever
by the rat is instrumental in providing food
(reinforcement). The response (pressing the lever) is
reinforced and the behavior is acquired or learned. The
pressing of lever by the rat is instrumental in getting the
food, a satisfying consequence (positive reinforcement)
and that is why this type of learning is also called
instrumental learning. It is also called operant
conditioning because the behavior of rat or any
organism is a kind of operation on the environment13.
Non Associative Learning
Non associative learning refers to a relatively permanent
change in the strength of response to a single stimulus
due to repeated exposure to that stimulus. Learning
involving exposure usually to a single event and that is
presumed not to reflect learning of a relationship
between multiple events. Changes due to such factors as
sensory adaptation, fatigue or injury do not qualify as
non associative learning. It is not necessary that the
animal learns to associate the stimuli involved (thus the
name). For example, we learn language by limitation of
people who already speak. This involves no association
of stimuli and is clearly more complicated than
habituation14.
Habituation
Habituation is a form of learning in which an organism
decreases or ceases to respond to a stimulus after
repeated presentations. Essentially, the organism learns
to stop responding to a stimulus which is no longer
biologically relevant. For example, organisms may
habituate to repeated sudden loud noises when they
learn these have no consequences15-16.
Sensitization
Sensitization is a non-associative learning process in
which repeated administration of a stimulus results in
the progressive amplification of a response.
Sensitization often is characterized by an enhancement
of response to a whole class of stimuli in addition to the
one that is repeated. In sensitization, a stimulus to one
pathway enhances reflex strength in another. An
example, again taken from experiments in Aplysia and
repetition of a painful stimulus may make one more
responsive to a loud noise17.
TYPES OF MEMORY
Sensory Memory
Sensory memory holds sensory information less than
one second after an item is perceived. The ability to look
at an item and remember what it looked like with just a
split second of observation or memorization is the
example of sensory memory. It is out of cognitive
control and is an automatic response. With very short
presentations, participants often report that they seem to
“see” more than they can actually report. The first
experiments exploring this form of sensory memory
were precisely conducted by using the partial report
paradig18.
Three types of sensory memories exist. Iconic
memory is a fast decaying store of visual information; a
type of sensory memory that briefly stores an image
which has been perceived for a small duration. Echoic
memory is a fast decaying store of auditory information,
another type of sensory memory that briefly stores
sounds that have been perceived for short
durations. Haptic memory is a type of sensory memory
that represents a database for touch stimuli19.
Short Term Memory
Short term memory is also known as working memory.
Short term memory allows recall for a period of several
seconds to a minute without rehearsal. Its capacity is
also very limited. Short term memory is believed to rely
mostly on an acoustic code for storing information, and
to a lesser extent a visual code. Confusion with recalling
acoustically similar letters rather than visually similar
letters implies that the letters were encoded acoustically.
Deals with the encoding of written text; thus, while
memory of written language may rely on acoustic
components, generalizations to all forms of memory
cannot be made20.
Long Term Memory
Long term memory can store much larger quantities of
information for potentially unlimited duration
(sometimes a whole life span). Its capacity is
immeasurable. For example, given a random seven digit
number we may remember it for only a few seconds
before forgetting, suggesting it was stored in our short
term memory. On the other hand; we can remember
telephone numbers for many years through repetition;
this information is said to be stored in long-term
memory. While short-term memory encodes information
acoustically, long term memory encodes it
semantically21. Long term memory, on the other hand, is

Gupta et al Journal of Drug Delivery & Therapeutics. 2018; 8(2):153-157
ISSN: 2250-1177 [156] CODEN (USA): JDDTAO
maintained by more stable and permanent changes in
neural connections widely spread throughout the brain.
The hippocampus is essential (for learning new
information) to the consolidation of information from
short term to long term memory, although it does not
seem to store information itself22.
Declarative Memory
Declarative memory or explicit memory is a memory
system that is controlled consciously, intentionally and
flexibly. A non associative theory of human long term
memory according to which the mind lays down a
continuous record of experience (trace column), much
like a videotape Declarative memory generally involves
some effort and intention and we can employ memory
strategies such as mnemonics to recall information it is
mediated by the hippocampus and frontal lobes and thus
damage to these areas may compromise declarative
memory. For example people with damage to the
hippocampus have difficulty forming new long term
declarative memories, while those with frontal lobe
damage may experience deficits in working memory.
Such as recall and recognition, in which an individual is
fully aware that he or she is being tested. It generally
declines with age. Examples include recalling the name
of an old friend, remembering a list of items to pick up
at the store, remembering information for a test and
learning a phone number23.
Implicit Memory
No declarative memory or implicit memories are stored
differently depending upon how they are acquired. “Fear
conditioning” (training that involves use of fearful
stimuli) involves the amygdale. Operant conditioning
involves the striatum and cerebellum9. For example; eye
blink conditioning is disrupted by lesions of the dentate
and interpositus nuclei of the cerebellum. Classical
conditioning, sensitization and habituation involve the
sensory and motor systems involved in producing the
motor responses being conditioned. Perhaps
surprisingly, certain simple reflexes mediated by the
spinal cord can be classically conditioned even after the
cord has been surgically isolated from the brain. So, it
appears that all regions of the nervous system may be
capable of memory storage. Priming is an automatic or
unconscious process that can enhance the speed and
accuracy of a response as a result of past experience.
Different cues (see examples below) prompt the
retrieval of memory. Memories are stored as a series of
connections that can be activated by different kinds of
cues; there is not any single location in the brain
associated with a specific memory trace. Priming helps
trigger associated concepts or memories, making the
retrieval process more efficient24.
THE LEARNING CYCLE
The learning cycle consists of four stages: gather
sensory experiences through the sensory, cortices;
engage in reflective observation, drawing on the
temporal lobe; create new concepts in the prefrontal
cortex; and actively test through our motor cortices25.
The complete cycle of learning arises from the very
structure of the brain and results in new and lasting
physical connections. Gathering; the first part of the
cycle involves gathering information. This step engages
the sensory cortices, which receive input from the
outside world in the form of vision, hearing, touch,
position, smell and taste26. Reflection; the second part of
the cycle, engages the temporal lobe. During reflection,
the brain integrates the sensory information received
during the gathering stage. Creation; is the point in the
learning cycle at which the learner shifts from receiving
and absorbing information to creating knowledge in the
form of abstractions such as ideas, plans ,concepts and
symbolic representations27.
MEMORY PROCESS
When information comes into our memory system (from
sensory input), it needs to be changed into a form that
the system can cope with, so that it can be stored.
Evidence suggests that this is the principle coding
system in short term memory (STM) is acoustic coding.
When a person is presented with a list of numbers and
letters, they will try to hold them in STM by rehearsing
them (verbally). Rehearsal is a verbal process regardless
of whether the list of items is presented acoustically
(someone reads them out) or visually (on a sheet of
paper) 28.
The principle encoding system in long term memory
(LTM) appears to be semantic coding (by meaning).
However, information in LTM can also be coded both
visually and acoustically. Encoding” refers to the
processes involved in the transformation of an event in
the world into a representation in your mind/brain. By
analogy, imagine that you are writing or speaking to a
friend in a secret code: you have a message, and you
transform that message into the code with the hopes that
your friend can decode it (akin to retrieval). Similarly,
memory scientists assume that events are transformed
into mental representations by encoding processes. A
considerable amount of memory research has examined
ways that events are encoded by manipulating the way
people process materials during study episodes29.
Memory Storage
This concerns the nature of memory stores, i.e. where
the information is stored, how long the memory lasts for
(duration), how much can be stored at any time
(capacity) and what kind of information is held. The
way we store information affects the way we retrieve it.
There has been a significant amount of research
regarding the differences between STM and LTM. Most
adults can store between 5 and 9 items in their STM30.
Memory Retrieval
This refers to getting information out storage. If we
can’t remember something, it may be because we are
unable to retrieve it. When we are asked to retrieve
something from memory, the differences between STM
and LTM become very clear28. STM is stored and
retrieved sequentially. For example; if a group of
participants are given a list of words to remember and
then asked to recall the fourth word on the list,
participants go through the list in the order they heard it
in order to retrieve the information. LTM is stored and
retrieved by association. This is why you can remember

Gupta et al Journal of Drug Delivery & Therapeutics. 2018; 8(2):153-157
ISSN: 2250-1177 [157] CODEN (USA): JDDTAO
what you went upstairs for if you go back to the room
where you first thought about it. Organizing information
can help aid retrieval. You can organize information in
sequences (such as alphabetically by size or by time).
Imagine a patient being discharged from hospital whose
treatment involved taking various pills at various times,
changing their dressing and doing exercises. If the
doctor gives these instructions in the order which they
must be carried out throughout the day (i.e. in sequence
of time), this will help the patient remember them. The
next sections are focused on a few of the core concepts
in the scientific study of memory. An important idea is
that each experience leaves behind some kind of
memory trace, a representation of the event, in a
person’s mind/brain. The exact nature of memory traces
has not been specified by memory scientists31 but the
idea that memory traces exist is useful for explaining
memory phenomena. Retrieval then refers to processes
involved in reconstructing what occurred at a particular
place and time. Memory scientists assume that retrieval
processes are always initiated by retrieval cues,
identifiable triggers for retrieval processes and that the
experience of remembering occurs when retrieval cues
interact with information in memory traces32. There
must be some information about what you did last night
stored in your mind (a memory trace) and your
remembrance of the past happens because the retrieval
cue interacts with the trace information. This section
highlights foundational research and review articles on
retrieval processes; beginning with Tulving’s influential
work on the importance of retrieval cues provides an
accessible introduction to the idea that the
distinctiveness or uniqueness of retrieval cues is a
critical determinant of remembering33.
CONCLUSION
Different types of learning and memory were discussed
in the present study. An attempt has been made here to
collect all available information about the learning and
memory which would enable the researchers to get help
during their research.
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