Memory
Chapter 6
Part II
William G. Huitt
Last revised: May 2005
Factors Influencing Retrieval
• Serial position effect
– The tendency to remember the beginning and
ending items of a sequence or list better than the
middle items
– Primacy effect
• The tendency to recall the first items on a list more readily
than the middle items
– Recency effect
• The tendency to recall the last items on a list more readily
than the middle items
Factors Influencing Retrieval
• Environmental context and memory
– any elements of the physical setting in which a
person learns information are encoded along with
the information and become part of the memory
trace
– Memories are better recalled in the environment
they were learned
Factors Influencing Retrieval
• State-dependent effect
– The tendency to recall information better if one is in
the same pharmacological or psychological (mood)
state as when the information was encoded
– Participants learned (encoded) material while sober
or intoxicated, and later were tested in either the
sober or intoxicated state
• Recall was found to be best when the participants were in
the same state for both learning and testing
– Evidence does suggest that anxiety and fear
influence memory
• Adults who are clinically depressed tend to recall more
negative life experiences and are likely to recall their
parents as unloving and rejecting
Biology and Memory
• Hippocampus and hippocampal region
– Hippocampal region
• A part of the limbic system which includes the
hippocampus itself and its underlying cortical areas
– Research has established that the hippocampus is
critically important for storing and using mental
maps to navigate in the environment
Biology and Memory
• Hormones and memory
– McGaugh and Cahill
• Suggest that there may be two pathways for forming
memories – one for ordinary information and another for
memories that are fired by emotion
• When a person is emotionally aroused, the adrenal glands
release the hormones adrenalin and noradrenaline into the
bloodstream
– Excessive levels of the stress hormone cortisol
have been shown to interfere with memory in
patients who suffer from diseases of the adrenal
glands
– Estrogen, the female sex hormone, appears to
improve working memory efficiency
Forgetting
• Causes of forgetting
– Encoding failure
• A cause of forgetting resulting from material never having
been put into long-term memory
– Decay theory
• A theory of forgetting that holds that the memory trace, if
not used, disappears with the passage of time
• Harry Bahrick and others
– Found that after 35 years, participants could recognize
90% of their high school classmates’ names and
photographs – the same percentage as for recent
graduates
Forgetting
• Causes of forgetting
– Interference--memory loss that occurs because
information or associations stored either before or
after a given memory hinder the ability to remember it
• Proactive interference
– Occurs when information or experiences already stored
in long-term memory hinder the ability to remember
newer information
• Retroactive interference
– Happens when new learning interferes with the ability to
remember previously learned information
Forgetting
• Causes of forgetting
– Consolidation failure--any disruption in the
consolidation process that prevents a permanent
memory from forming
• Retrograde amnesia
– A loss of memory affecting experiences that occurred
shortly before a loss of consciousness
• Nader and others
– Demonstrated that conditioned fears in rats can be
erased by infusing into the rats’ brains a drug that
prevents protein synthesis
Forgetting
• Causes of forgetting
– Motivated forgetting
• Forgetting through suppression or repression in order to
protect oneself from material that is too painful, anxiety- or
guilt-producing, or otherwise unpleasant
• Repression
– Removing from one’s consciousness disturbing, guiltprovoking, or otherwise unpleasant memories so that
one is no longer aware that a painful event occurred
• Prospective forgetting
– Forgetting to carry out some action, such as mailing a
letter
Forgetting
• Causes of forgetting
– Amnesia
• A partial or complete loss of memory resulting
from brain trauma or psychological trauma
– Retrieval failure
• Endel Tulving
– Claims that much of what people call forgetting is really
an inability to locate the needed information
– Found that participants could recall a large number of
items they seemed to have forgotten if he provided
retrieval cues to jog their memory
Improving Memory
• How information is organized strongly
influences your ability to remember it
• Overlearning
– Practicing or studying material beyond the point
where it can be repeated once without error
– Research suggests that people remember material
better and longer if they overlearn it
– Krueger--Showed very substantial long-term gains
for participants who engaged in 50% and 100%
overlearning
Improving Memory
• Massed practice
– Learning in one long practice session as opposed to
spacing the learning in shorter practice sessions
over an extended period
– Long periods of memorizing make material
particularly subject to interference and often result in
fatigue and lowered concentration
Improving Memory
• Distributed practice
– Spacing study over several different sessions
generally is more effective than massed practice
Recent research suggests that significant
improvement in learning results when spaced study
sessions are accompanied by short, frequent tests
of the material being studied
– The spacing effect applies to learning motor skills as
well as to learning facts and information
Improving Memory
• A. I. Gates
– Tested groups of students who spent the same
amount of time in study, but who spent different
percentages of that time in recitation and rereading
– Participants recalled two to three times more if they
increased their recitation time up to 80% and spent
only 20% of their study time rereading