Memory Systems | Psychology

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- Memory consists of three main systems,

sensory memory, short-term
memory, and long-term memory.

According to the Modal Model of Memory,

information passes from sensory memory

to short-term memory to long-term memory,

but not everything that
enters gets remembered

as information can be lost
at any stage in the process

unless strategies are used to maintain it.

Sensory memory is the storage
of information from the senses

that last a few seconds or less

before passing into short-term memory.

There are two main
types of sensory memory,

iconic memory, and echoic memory.

Iconic memory is a fast-decaying
store of visual information

that lasts less than a second.

Echoic memory is a fast-decaying store

of auditory information

that lasts about three to four seconds.

Paying attention to sensory
memories allows people

to work with that information
in short-term memory.

A system for storing information

for more than a few seconds,
but less than a minute.

Sometimes the term working memory

is used to refer to information
in short-term storage

that is actively being processed

Without rehearsal, information
in short-term memory

will be quickly forgotten

through the natural decay
of information over time.

Long-term memory is the system

that stores facts, experiences, and skills

for periods ranging from a
few minutes to a lifetime.

Reviewing and rehearsing
information in short-term memory

can move it into long-term memory.

Although not all information

in long-term memory is preserved forever.

It may be stored, but inaccessible

due to problems retrieving
the information.

It can also be forgotten
due to interference

from earlier or later learning.

This leads us to an important point.

It is easy to think of
this as a one-way system,

but information is always
flowing in both directions.

Think about using long-term memory

to cook a favorite recipe.

You're going to draw on sensory memory

for auditory and visual information,

like to know when your water is boiling

and prepping the food in front of you,

but your working memory will
also draw on long-term memories

to access stored facts and procedures,

like how you've prepared
this meal in the past

and what changes you
normally make to the recipe.

This is a complex task that
requires the coordination

of multiple subsystems of storage,

as well as the manipulation of information

that is being processed

and a central executive
system to control it

and manage the flow of data in
and out of these subsystems.

It's amazing, but it's also something

that we do every minute of every day.

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