If you know that a Porsche is a car, you know that a Porsche has brakes, even if you have not actually seen them, because you know that all cars have brakes. This highly useful form of reasoning is called inference, and it is based essentially on knowledge that we already have stored in our memories. The more knowledge we have already acquired, the more we will be able to draw inferences.
MEMORY AND LEARNING
Memory and learning are so closely connected
that people often confuse them with each other. But the specialists
who study them consider them two distinct phenomena.
These specialists define learning as a
process that will modify a subsequent behaviour.
Memory, on the other hand,
is the ability to remember past experiences.
You learn a new language by studying it, but you then speak it
by using your memory to retrieve the words that you have learned.
Memory is essential to all learning, because it lets you store
and retrieve the information that you learn. Memory is basically
nothing more than the record left by a learning process.
Thus, memory depends on learning. But learning also depends on
memory, because the knowledge stored in your memory provides the
framework to which you link new knowledge, by association. And
the more extensive your framework of existing knowledge, the more
easily you can link new knowledge to it.
Human memory is not a unitary process. Research suggests, that,
at the psychological level, various types of memory are at work
in human beings. It also seems increasingly likely that these
various systems bring different
parts of the brain into play.
Types of memory can be classified in a
number of ways, depending
on the criterion used. With duration as the criterion,
at least three different types of memory can be distinguished:
sensory memory, short-term memory, and long-term memory.
Sensory memory takes the information
provided by the senses and retains it accurately but very
briefly. Sensory memory lasts such a short time (from a
few hundred milliseconds to one or two seconds) that it
is often considered part of the process of perception.
Nevertheless, it represents an essential step for storing
information in short-term memory.
Short-term memory temporarily records the succession
of events in our lives. It may register a face that we
see in the street, or a telephone number that we overhear
someone giving out, but this information will quickly
disappear forever unless we make a conscious effort to
retain it. Short-term memory has a storage capacity of
only about seven items and lasts only a few dozen seconds.
Just as sensory memory is a necessary step for short-term
memory, short-term memory is a necessary step toward
the next stage of retention, long-term memory.
Long-term memory not only stores all the significant
events that mark our lives, it lets us retain the meanings
of words and the physical skills that we have learned.
Its capacity seems unlimited, and it can last days, months,
years, or even an entire lifetime! But it is far from infallible.
It sometimes distorts the facts, and it tends to become
less reliable as we age.
Long-term
memory as a whole is defined by the criterion of long duration.
But other criteria can
be applied to break down the complex phenomenon of memory
into separate components.
One such criterion is whether or not the long-term memory
in question can be verbalized. On the basis of this criterion,
two main forms of long-term memory can be distinguished.
The first is declarative memory:
your memory of all those things that you are aware of remembering
and that you can describe in words, such as your birthday,
or the meaning of the word "cradle", or what you
ate last night. This form of memory is also called explicit
memory, because you can name and describe each of these remembered
things explicitly.
The other form of long-term memory is non-declarative
memory.
It is also known as implicit memory, because you express
it by means other than words. For example, when you ride a
bike, juggle some balls or simply tie your shoelaces, you are
expressing memories of motor skills that do not require the
use of language. Such "motor memories" are just one
type of implicit memory. There
are others as well.
