MEMORY: HOW DOES THIS CURIOUS BRAIN FUNTION WORK?
Simone Miguez Cunha (1) (2) & Adriana Benevides Soares (2)
(1) Instituto Militar de Engenharia - Seção Psicopedagógica
Praça General Tibúrcio, 80 - 22290-270 Rio de Janeiro, RJ
(2) Universidade Gama Filho – Programa de Pós-Graduação em Psicologia
Rua Manuel Vitorino, 533 – 20740-280 Rio de Janeiro - RJ
Memory is an extremely important brain function because it is the basis of all
learning. Our knowledge and abilities are stored in our memory, allowing us to orient
ourselves in space and time.
Knowledge representation happens in this memory
context and its processes help us to store and retrieve this knowledge for present and
future activities.
According to Sternberg (2000), "memory is the way we recall our past
experiences in order to use this information in the present."
Recent neuropsychological investigations about the workings of memory have
yielded a better understanding of its structure, organization and information processing
capabilities.
Up to fairly recently, cognitive psychologists thought that memory was an almost
static process, capable only of passively receiving information to store and
subsequently retrieve. In other words, information processing in memory would happen
sequentially, with information being coded first, then stored for some time and finally
extracted.
In the mid-1960s, investigations seemed to show that memory was
characterized by the information contained in its storage structures.
However, the investigations proceeded and yielded new data which led cognitive
psychologists to review the concept of memory and its mechanisms. In this way, new
models were developed due to different ways of interpreting the results or just as a
means to take new data into account.
In the last two decades, investigators were led to believe that memory is a
process which involves several operations that occur simultaneously and in parallel. Its
functioning allows these operations (coding, storage and retrieval) to interact
reciprocally and interdependently in information treatment.
MEMORY THEORETICAL MODELS
Most theoretical studies of the memory are based on one of two models, the
traditional and the alternative, which regard the memory structure and processes from
different points of view. One is focused on the study of the memory general structure,
while the other seeks to understand the structural organization of the semantic memory
(words or concepts).
Figure 1 summarizes the evolution of research according to its specific goals.
MEMORY
Traditional model
Alternative model
Two Structures Model - 1963
Three Storages Model - 1968
Memory General Structure
Semantic Memory Structure
Structure by Treatment
Hierarchical Structure of
Levels
Semantic Memory
1972
1969-1974
Multiple Memory Systems
Model
Network Model
1972
1975
Memory Alternative
Taxonomy
Connectionist Model
1986
Working Memory
1990
Figure 1: Evolution of research according to specific goals
The beginning of memory research is closed related to a "traditional" (Sternberg,
2000) memory model based on three kinds of storage: sensorial, short-term and longterm.
Sensorial storage: a structure that can store a very limited quantity of information for
brief periods. This structure was considered to be the initial store for many data that
subsequently were transferred to short-term and long-term storage.
Short-Term storage: a structure than can store information for somewhat longer
periods, but also with a very limited capacity. It can hold only seven items plus or minus
two. Due to this limited capacity, we developed mechanisms to control the flow of
information to short-term storage, repeating it, grouping it or making associations.
Long-Term storage: a structure that can store information for long periods of time.
This memory holds all the information we need in order to perform our day-to-day
activities: people's names, concepts, daily planning, etc.
This model emphasizes these structures as passive containers where information
is stored and assumes that memory processes have only a limited control on the
transfer of information from one storage structure to another.
The “alternative” model has as its key feature the concept of working memory, a
brief, transient storage structure that keeps the information active during several
minutes while it is being processed.
This idea emphasizes the control functions
performed by the memory, such as coding and integration of long-term storage. This
dynamic and continuous character of manipulation and coordination in information
integration is what distinguishes the alternative model.
The main goal of the
researchers who use the alternative model has been to understand how the words and
concepts are stored in our long-term memory, having in mind that the fundamental unit
of knowledge is the concept, an idea about something.
This interest of researchers in understanding the structural organization of
semantic memory contrasts with preceding theories, which sought to explain only the
memory general structure. Semantic memory deals with concepts, ideas a person can
associate with several features and to which she can connect other ideas. Several
models were developed with this goal in mind, but none could explain how the concepts
are stored in our semantic memory. Based on reviews and critics of these models, an
alternative model called connectionist model (parallel distributed processing or PDP)
was proposed.
According to this model, we manipulate several mental operations
simultaneously in order to organize our concepts, store them and ultimately recover
them from storage. This information storage is based on the idea of a network, i.e., a
series of labeled relationships between nodes, which represent words or concepts. In
this model, knowledge is represented by connections between nodes and not by the
nodes themselves. When we try to evoke some knowledge, we activate a node, which
can activate another node connected to it; this process of spreading activation leads to
the activation of additional nodes. This effect is called priming.
The PDP model is consistent with the concept of working memory, which is the
structure that takes the most recently activated part of the long-term memory and
transfers these activated elements in and out of transient memory storage. In other
words, the working memory creates a working area where bits of information are used
for immediate reasoning, problem solving or behavior guidance, but are soon forgotten.
According to Sternberg (2000), these models are hypothetical and are not
associated with real physiological structures, serving only as a mental model to describe
the mechanisms of memory.
Many cognitive psychologists use this model to describe memory phenomena
because it is closer to the functioning of the human brain, with it massive parallel
processing capabilities.
DIFFERENCES BETWEEN THE TWO MODELS
Traditional model (three kinds of storage)
 Sequential processing of information
 Can be simulated in individual computers
Alternative model (parallel processing, working memory)
 Parallel processing of information in neural networks
 Cannot be simulated in individual computers, but only in networks
MEMORY SYSTEMS
Could it be that driving a car and knowing the name of a famous Brazilian writer
are abilities that are processed exactly in the same manner? And how do we remember
them?
According to Larry Squire (in Sternberg, 2000), there is a difference between
declarative (explicit) memory and several kinds of non-declarative (implicit) memory
(Figure 2).
Other authors had already suggested the existence of more than one memory
system to organize and store information. They proposed making a distinction between
the semantic memory (concerned with words that describe time-independent events),
episodic memory (concerned with dates and similar time-dependent events) and
procedural memory (concerned with habits and abilities).
Different kinds of information are stored and retrieved by different mechanisms.
Semantic and episodic memories belong to the declarative (explicit) class; they deal
with words and the conscience is involved. Implicit (non-declarative) memory deals with
nonverbal concepts and the conscience is not involved.
This is the case with
procedures, abilities, habits, conditioned behavior and priming.
In this way, we can see a clear difference between memorizing numbers or dates
and activities such as driving a car, solving a puzzle, playing volleyball etc.
Memory
Declarative
Non-declarative
Semantic
Episodic
Procedural skills
Priming
Conditionin
Non-
(facts)
(events)
(motor,
(semantic
g
associative
procedural,
and
(habituation,
cognitive)
perceptive)
sensitization)
Figure 2: Difference between declarative and non-declarative memory
MEMORY DEVELOPMENT
Memory capacity can be affected by the physiological development of the brain,
by the acquisition of information, by new experiences, by environmental conditions and
by the use of metacognitive strategies.
The physiological development of the brain provides an increase in the
complexity of the neural networks, allowing for a more efficient information storage and
retrieval.
Bartlett (in Sternberg, 2000) has found that knowledge and a priori expectations
have a considerable influence on information retrieval, leading in some cases to
interference and distortion and in other cases to intensification of memory processes.
Our mental framework affects the way we remember what we have learned, making our
memory constructive.
When we integrate a new information to knowledge already stored in our
memory, we are associating something new to a preexisting mental framework; this
process is called consolidation.
We can increase our storage capacity during the
consolidation process by using several metamemory strategies.
We store different kinds of information in different ways; therefore, we have to
use specific mechanisms to transfer these different kinds of information into long-term
storage.
Repetition is a well-know strategy to facilitate this storage. The longer the time
dedicated to repetition, the longer will people be able to retain the information. However,
Sternberg (2000) points out that this transfer must be performed stimulating memory
organization in a way that new knowledge it significantly integrated to previous
information. When this is the case, the information will be retained for a longer time and
will be more easily retrieved.
The arrangement of information in memory is also important, since it can facilitate
memory operations, significantly decreasing the time needed for retrieval.
The above mentioned strategies are widely known, but there are some others,
such as the use of associated words, keywords and interactive images, which can also
improve memory efficiency.
The conclusion is that when you choose an information-coding strategy, you
should also worry about the strategies that will be used to recover this information.
All these factors contribute to memory development, leading to a more efficient
performance. In particular, this kind of study shows how people can use memory more
efficiently.
MEMORY PHYSIOLOGY
Neuropsychological research has shown that some brain structures are involved
in memory-related activities; memory, however, is not located in a specific region of the
brain. Its functions are probably shared by many different structures, located in different
regions, and therefore the loss of a certain brain function can sometimes be
compensated by another brain region. The main regions associated with memory are
(Figure 3):
Cerebral cortex: responsible for the long-term storage of information.
Hippocampus: responsible for the coding of declarative information. However, other
brain regions are responsible for other forms of declarative memory.
Basal ganglia: responsible for procedural memory.
Cerebellum: responsible for remembering classically conditioned responses.
Basal ganglia
Cerebral cortex
Cerebellum
Hippocampus
Figure 3: Main regions associated with memory
Neurotransmitters (serotonin, acetylcholine, noradrenalin and the hormones),
according to their production in the organism, may contribute positively or negatively to
memory function.
Memory loss can be due to the consumption of alcohol, which disturbs serotonin
activity, as well as to the altered psychological states of stress, anxiety and depression
and also to long-term use of some drugs and to vitamin B1 deficiency; all these factors
interfere with our learning capacity.
MEMORY AND LEARNING
Memory and learning are closely related; it would be impossible to acquire new
knowledge and modify it subsequently without being able to retain information. When
we store information, we construct a mental representation that helps us use what has
been learned to solve present and future problems.
According to Pozo (1998), research on information handling by the brain is not
enough to provide us with a theory of learning, since these studies approach learning
and memory as a whole, without studying each of these processes separately.
However, many scientific studies suggest a very strong correlation between the two
processes.
These studies show that information retrieval is affected by the way it is coded.
When we try to learn something, our performance will improve if try to relate the new
knowledge to old knowledge in several different ways. If one takes care to diversify the
codification context, retention can be significantly improved. It is possible to use this
strategy to facilitate the development of this principle through project pedagogy.
For long-term retention of information, learning must be distributed along several
sessions. This concept can be integrated in the curricular grid so as to foster the
organization of courses and classes.
Research has shown that we remember better when we can relate the
information to our mental constructs and our personal experience. In other words, when
we make our own clues we have a much higher retention rate than when other people
make clues for us. Therefore, one has to ponder about the necessity of revising the
teacher's role so that he does not become a central and exclusive element in the
learning process and so that learning is not confused with temporary memorization of
information utterly divorced from the student daily activities and social reality. School
practice oriented so that the student can think and reflect about his own process of
knowledge construction enables him to elaborate the new information is a way that is
significant to him, integrating it into his previous knowledge.
In this way, memory
performance is improved and the student becomes more independent.
Finally, these discoveries can contribute to the processes of teaching and
learning, helping the student to construct his knowledge and improving his performance.
The contribution of these conquests to Education and Psychology seem to be
uncontestable, having in mind the broadness of their applicability.
BIBLIOGRAPHY
POZO, J. I. (1998) - Teorias Cognitivas da Aprendizagem. Porto Alegre: Artes Médicas
Sul, 1998.
STERNBERG, R. J. (2000) - Psicologia Cognitiva. Porto Alegre: Artes Médicas Sul,
2000.