CHAPTER 8: MEMORY
PART I: OVERVIEW OF MEMORY
- Memory: the cognitive processes of encoding, storing, and retrieving information.
- Encoding: the process by which sensory information is converted into a form that can
be used by the brains memory system.
- Storage: the process of maintaining information in memory,
- Retrieval: the active process of locating and using stored information.
- In 1949, Donald Hubb used this active/latent distinction to suggest tat the brain re-
membered info in 2 different ways, a view known today as dual trace theory.
- Information that was active was in this state because neurons were firing continuously.
- Hebb thought that this activity was due to the feedback circuits of neurons.
- The brain therefore retained traces of an experience either in an active state or in the
latent structural state.
- In the 1960s, Richard Atkinson and Richard Schiffon suggested a way of thinking
about memory that psychologists have found useful.
- They proposed that memory takes at least three forms: sensory memory, short term
memory, long term memory.
- The first 2 roughly correspond to memory systems that retain active traces, while the
last retains latent traces.
- Sensory memory: memory in which representations of the physical features of a stimu-
lus are stored for very brief durations.
- This form of memory is difficult to distinguish from the action of perception.
- The info contained in sensory memory represents the original stimulus fairly accurately
and contains all or most of the info that has just been perceived.
- The function of sensory memory appears to be to hold info long enough of it to be-
come part of the next form of memory: short term memory.
- Short-term memory: an immediate memory for stimuli that have just been perceived. It
is limited in terms of both capacity (7+ 2 chunks of information) and duration (less than
- Long-term memory: memory in which information is represented on a permanent or
- The implication that information flows from one type of memory to another has been
termed the modal model of memory because it seems to be so widely assumed.
PART II: SENSORY MEMORY Iconic Memory
- Iconic memory: a form of sensory memory that holds a brief visual image of a scene
that has just been perceived; also known as visible persistence.
- Echoic memory: a form of sensory memory for sounds that have just been perceived.
- Echoic memory holds a representation of the initial sounds until the entire word has
PART III: SHORT-TERM OR WORKING MEMORY
Encoding of Information in the Short Term: Interaction with Long-Term Memory
- Information can enter short-term memory form 2 directions: from sensory memory or
from long-term memory.
- Working memory: memory for new information and information retrieved from long-
term memory; used in this text as another name for short-term memory.
Primacy and Recency Effects
- Primacy effect: the tendency to remember initial information. In the memorization of a
list of words, the primacy effect is evidenced by better recall of the words early in the list.
- Recency effect: the tendency to recall later information. In the memorization of a list of
words, the recency effect is evidenced by better recall of the last words in the list.
- The primacy effect appears to be due to the fact that words earlier in a list have the op-
portunity to be rehearsed more than do words in other parts of a list.
- The recency effect appears to be due to the fact that words at the end of the list were
the last to be heard they are still available in short-term memory.
The Limits of Working Memory
- john brown (1958) and lloyd and margaret peterson (1959): stimuli remain working
memory for less than 20 seconds unless they are rehearsed.
- Muter (1980): found that an unexpected distractor seriously disrupted working memory:
most people found it hard to recall three letters after only 2 seconds.
- Miller (1956): in a paper entitled the magical number seven, plus or minus 2 demon-
strated that people could retain, on average, about seven pieces of info in their short
term memories: seven numbers, seven letters, seven unrelated words, or seven tones of
a particular pitch.
- Chunking: a process by which information is simplified by rules, which make it easily
remembered once the rules are learned. For example, the string of letters GSTCBCR-CMP are easier to remember if a person learns the rule that organizes them into smaller
chunks: GST, CBC, RCMP.
- The actual limit of short term memory is seven chunks, not necessarily seven individu-
al items. Thus, the total amount of information we can store in short term memory de-
pends on the particular rules we use to organize it.
- The capacity of short term memory for verbal material is not measured in letters, sylla-
bles, or words, but instead depends on how much meaning the information has.
- When the items are related we can store many more of them.
Varieties of Working Memory
- Baddeley (1993, 2000): suggested that working memory consists of several compo-
nents, all coordinated by a central executive function.
- > Phonological Working Memory
- Evidence suggests that the short term storage of words, whether originally presented
visually or acoustically occur in phonological short term memory.
- Phonological short-term memory: short term memory for verbal information.
- Phonological memory may be produced by activity in the auditory system- say, circuits