Memory Processes
Memory is essentially the capacity for storing
and retrieving information. Three processes are involved in memory: encoding,
storage, and retrieval. All three of these processes determine whether
something is remembered or forgotten.
Encoding
Processing information into memory is
called encoding. People automatically encode some types of
information without being aware of it. For example, most people probably can
recall where they ate lunch yesterday, even though they didn’t try to remember
this information. However, other types of information become encoded only if
people pay attention to it. College students will probably not remember all the
material in their textbooks unless they pay close attention while they’re
reading.
There are several different ways of encoding
verbal information:
·
Structural encoding focuses on what words look like. For
instance, one might note whether words are long or short, in uppercase or
lowercase, or handwritten or typed.
·
Phonemic encoding focuses on how words sound.
·
Semantic encoding focuses on the meaning of words. Semantic
encoding requires a deeper level of processing than structural or phonemic
encoding and usually results in better memory.
Storage
After information enters the brain, it has to
be stored or maintained. To describe the process of storage, many psychologists
use the three-stage model proposed byRichard Atkinson and Richard
Shiffrin. According to this model, information is stored sequentially in
three memory systems: sensory memory, short-term memory, and long-term memory.
Sensory Memory
Sensory memory stores incoming
sensory information in detail but only for an instant. The capacity of sensory
memory is very large, but the information in it is unprocessed. If a flashlight
moves quickly in a circle inside a dark room, people will see a circle of light
rather than the individual points through which the flashlight moved. This
happens because sensory memory holds the successive images of the moving
flashlight long enough for the brain to see a circle. Visual sensory memory is
called iconic memory; auditory sensory memory is called echoic
memory.
Short-Term Memory
Some of the information in sensory memory
transfers to short-term memory, which can hold information for
approximately twenty seconds. Rehearsing can help keep information in
short-term memory longer. When people repeat a new phone number over and over
to themselves, they are rehearsing it and keeping it in short-term memory.
Short-term memory has a limited capacity: it
can store about seven pieces of information, plus or minus two pieces. These
pieces of information can be small, such as individual numbers or letters, or
larger, such as familiar strings of numbers, words, or sentences. A method
called chunking can help to increase the capacity of short-term memory. Chunking combines
small bits of information into bigger, familiar pieces.
Example: A person confronted
with this sequence of twelve letters would probably have difficulty remembering
it ten seconds later, because short-term memory cannot handle twelve pieces of
information: HO TB UT TE RE DP OP CO RN IN AB OW L However, these letters can
be easily remembered if they’re grouped into six familiar words, because
short-term memory can hold six pieces of information: HOT BUTTERED POPCORN IN A
BOWL
Working Memory
Psychologists today consider short-term memory
to be a working memory. Rather than being just a temporary
information storage system, working memory is an active system. Information can
be kept in working memory while people process or examine it. Working memory
allows people to temporarily store and manipulate visual images, store
information while trying to make decisions, and remember a phone number long
enough to write it down.
Long-Term Memory
Information can be transferred from short-term
memory to long-term memory and from long-term memory back to short-term
memory. Long-term memory has an almost infinite capacity, and
information in long-term memory usually stays there for the duration of a
person’s life. However, this doesn’t mean that people will always be able to
remember what’s in their long-term memory—they may not be able to retrieve information
that’s there.
Organization of
Memories
Imagine what would happen if a psychology
textbook weren’t organized by section, by chapter, or in any other way. Imagine
if the textbook didn’t have a table of contents or an index. If the textbook
just contained lots of information in a random order, students would have
difficulty finding a particular concept, such as “encoding of memory.” They’d
know the information was in there somewhere, but they’d have trouble retrieving
it.
Long-term memory stores much more information
than a textbook, and people would never be able to retrieve the information
from it if it weren’t organized in some way.
Psychologists believe one way the brain
organizes information in long-term memory is by category. For example, papaya may
be organized within the semantic category fruit. Categories can
also be based on how words sound or look. If someone is struggling to remember
the word papaya, she may remember first that it’s a three-syllable
word, that it begins with the letter p, or that it ends with the
lettera.
Long-term memory organizes information not
only by categories but also by the information’s familiarity, relevance, or
connection to other information.
Where Were You When . . .
Flashbulb memories are vivid, detailed
memories of important events. Older people may have very clear memories of
where they were and what they were doing when they heard President John F.
Kennedy had been assassinated. Many people today may have a similar kind of
memory of where they were when they heard the Pentagon and the World Trade
Center had been attacked by terrorists.
Retrieval
Retrieval is the process of getting information
out of memory. Retrieval cues are stimuli that help the
process of retrieval. Retrieval cues include associations, context, and mood.
Lost Memories
The fact that people can often recall lost
memories when hypnotized suggests that information in long-term memory is
usually not lost— it may just be difficult to retrieve.
Associations
Because the brain stores information as
networks of associated concepts, recalling a particular word becomes easier if
another, related word is recalled first. This process is called priming.
Example: If Tim shows his
roommate a picture of sunbathers on a nude beach and then asks him to spell the
word bear, the roommate may be more likely to spell bare because
the picture primed him to recall that form of the word.
Context
People can often remember an event by placing
themselves in the same context they were in when the event happened.
Example: If a woman loses her
car keys, she may be able to recall where she put them if she re-creates in her
mind exactly what she did when she last came in from parking her car.
Mood
If people are in the same mood they were in
during an event, they may have an easier time recalling the event.
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