Chapter 8 - Memory
Memory- refers to the processes that allow us to record and later retrieve experiences and information.
Encoding – refers to getting information into the system by translating it into a neural code that your
(* similar to the computer translates what you typed with the keyboard into an electrical code that
computer can process and understand.)
Storage – involves retaining saved information over time.
(* similar to a computer storing information on its hard drives.)
Retrieval- is the process of accessing information in long-term memory.
(* similar to viewing a file stored on the hard drive.)
Encoding Working Encoding Long-term
Sensory Sensory (Short-term) Memory
Input Registers Attention Memory
In this model, memory has three major components:
1. Sensory registers, which detect and briefly hold incoming sensory information;
2. Working memory, which processes certain information retrieved from the sensory registers and
information retrieved from long-term memory;
3. Long-term memory, which stores information for longer periods of time.
Sensory memory- holds incoming sensory information just long enough for it to be recognized. It is
composed of different subsystems, called sensory registers, which are the initial information processors.
(Ex: visual sensory register - iconic store; auditory sensory register – echoic store.)
Because our attentional capabilities are limited, most information in sensory memory simply
fades away. But through selective attention, a small portion enters short-term memory (aka: working
memory), which holds the information that we are conscious of at any given time.
Mental representations - Once information leaves sensory memory, it must be represented by some type
of code if it is to be retained in short-term and eventually long-term memory.
For example, the words that someone just spoke to you, the phone number that you just looked up must
somehow become represented in your mind. Such mental representations, or memory codes, can take
- mental image (visual encoding)
- code something by sound (phonological encoding) *which plays an important role in ST
- focus on the meaning of a stimulus (semantic encoding)
- code patterns of movement (motor encoding)
Capacity and duration – ST memory is limited in duration and capacity. Depending on the stimulus,
most people can hold no more than 5-9 meaningful items in STM.
1 Chunking – combining individual items into larger unites of meaning.
Maintenance rehearsal – a simple repetition of information. Ex: repeating a telephone number to
Elaborative rehearsal – involves focusing on the meaning of information or relating it to other things we
already know. Thus you could rehearse the term “iconic memory” by thinking about examples of it in
your own life.
Both types of rehearsal keep information in STM, but elaborative rehearsal is more effective in
transferring information into LTM, which is our more permanent memory store.
One model, proposed byAlan Baddeley, divides working memory into three components:
1) We maintain some information in an auditory working memory (when you repeat a phone
number, name, or vocab.).
2) Visual-spatial working memory allows us to temporarily store and manipulate images and spatial
information (as when forming mental “maps” of the route to some destination).
3) Acontrol process, called the central executive, directs the action. It decides how much attention
to allocate to mental imagery and auditory rehearsal, calls up information from LTM, and
integrates the input.
LTM is our vast library of more durable stored memories. Its capacity essentially is unlimited.
Once formed, a LTM can endure for up to a lifetime.
Studies found that the words at the end and beginning of a list of 10 – 30 items of words are the easiest to
recall. This U- shaped pattern is called the serial position effect, meaning that recall is influenced by a
word’s position in a series of items.
The serial position effect has two components:
- a primacy effect, reflecting the superior recall of early words. As the first few words enter STM,
they are quickly rehearsed and transferred into LTM. However, as the STM rapidly fills up and
there are too many words to keep track, we cannot rehearse the items and get them to the LTM.
- a recency effect, representing the superior recall of the most recent words. The last few words
have the benefit of not being “bumped out” of STM by new information.
Encoding: entering information
-effortful processing, encoding that is initiated intentionally and requires conscious attention.
Ex: rehearsing, making lists, and taking class notes…
-automatic processing, encoding that occurs without intention and requires minimal attention.
Ex: information about the frequency, spatial location, sequence, and timing of events…
-according to the levels of processing concept developed by Fergus Craik and Robert Lockhart of the U
of T, the more deeply we process information, the better it will be remembered. (Semantic encoding >
phonological encoding > structural encoding)
- Shallow exposures to a stimulus do not guarantee long-term retention. Rehearsal goes beyond mere
exposure because we are thinking about the information.
- Maintenance rehearsal involves simple repetition (repeating phone number), most useful for keeping
information active in short-term memory. However, it is an inefficient method for bringing about long-
2 - Elaborative rehearsal focuses on the meaning of information. Organizing information, thinking about
how it applies to our own lives, and relating it to concepts or examples we already know, more effective
in transferring information into long-term memory.
- organizing material in a hierarchy takes advantage of the principle that memory is enhanced by
associations between concepts.
- Chunking refers to combing individual items into a larger unit of meaning, and it widens the
information-processing bottleneck caused by the limited capacity of short-term memory.
Ex: when you call someone who lives far away, you probably encode the numbers as a set of three chunks
(e.g. 905-567-5456) rather than as ten individual numbers.