Chapter 7
Memory
Memory
• Memory is a general term for the storage,
retention and recall of events, information and procedures.
• The quality of an individual’s memory may vary based upon the nature of the information being retained and recalled, the level of interest in it, and its significance to that individual.
Module 7.1
Ebbinghaus’s Pioneering Studies of Memory • Hermann Ebbinghaus studied his own ability to
memorize new material
– He invented over 2300 nonsense syllables and put them into random lists.
– Over 6 years he memorized thousands of lists of nonsense syllables.
– Generally he found that delay between
memorization and recall caused forgetting of a large portion of the material.
Figure 7.1
Figure 7.1 Hermann Ebbinghaus pioneered the scientific study of memory by observing his own capacity for memorizing lists of nonsense syllables.
Ebbinghaus’s Pioneering Studies of Memory • Lists and serial-order effects
– We tend remember the beginning and end of a list of related items better than the middle.
• The primacy effect is the tendency to remember the beginning of the list.
• The recency effect is the tendency to
Ebbinghaus’s Pioneering Studies of Memory
• Meaningfulness and distinctiveness
– Another feature of Ebbinghaus’ work is that he memorized nonsense syllables.
– Studies of memory show meaningful materials are easier to remember.
– Distinctive or unusual information is easier to retain.
– The tendency of people to remember unusual items better than more common items is called the von Restorff effect.
Ebbinghaus’s Pioneering Studies of Memory • Dependence of memory on the method of
testing
– It is possible that since Ebbinghaus required himself to repeat the syllables in correct order after memorizing them, he underestimated his actual retention of the information.
• How well one appears to remember
something depends in part on how one is tested after learning.
Ebbinghaus’s Pioneering Studies of Memory • Dependence of memory on the method of testing
– Recall (or free recall) is the simplest method for the tester but the most difficult for the
person being tested. To recall something is to produce it, as is done on essay and
short-answer tests.
– Cued recall gives the person being tested significant hints about the correct answer. A fill-in-the-blank test uses this method.
What do these letters stand for?
• H.M. M.M.
• J.A. V.H.
• A.C. • A.C.D. • M.A. • L.T. • J.K. • G.C. • C.D.
Table 7.1
Ebbinghaus’s Pioneering Studies of Memory
• Dependence of memory on the method of testing – Recognition requires the person being tested to
identify the correct item from a list of choices.
Multiple-choice tests use the recognition method. – The savings (relearning) method compares the
speed at which someone relearns material
against learning something new. The amount of time saved between the original learning and the relearning is a measure of memory.
Other Memory Distinctions
– Declarative memory is the ability to state a fact. – Procedural memory is the memory of how to do
something.
– Long-term declarative memory is classified as either semantic (dealing with principles of
knowledge) or episodic (containing events and details of life history.)
• Your memory of a recent piano lesson is
declarative and episodic; your memory of how to read music is semantic; your memory of
Ebbinghaus’s Pioneering Studies of Memory • All of the processes that were tested by
Ebbinghaus involved explicit memory – memory that we are aware we are using.
• Implicit or indirect memory is the other major memory process. It is any experience that influences us without our awareness.
• Priming is a process that activates implicit memory.
Ebbinghaus’s Pioneering Studies of Memory • We are indebted to Ebbinghaus for initiating the
scientific study of memory.
• We have also learned important facts about the nature of memory from his difficulties with
Concept Check
The bonus question on your Introductory
Psychology test asks you to name the stages of the human sleep cycle. What type of memory test is this?
Concept Check
You are on a game show and the question that you must answer is “_________ is the city that is home to the Eiffel Tower, the Louvre, and the
Cathedral of Notre Dame.” What type of memory test is this?
Concept Check
You answer more questions on the subject of molecular biology correctly on the
comprehensive semester final than you did on the chapter test two months earlier. What
concept describes this?
Concept Check
While at a hardware store, you are looking at
several shades of light green paint trying to pick the one that matches the color on the walls of your home. What type of memory test is this?
The Information-Processing View of Memory • The information-processing model of memory
draws an analogy between a computer and the workings of memory in the human brain.
– According to this view, information enters the system, is processed and coded in various ways, and is then stored.
Figure 7.4
Figure 7.4 The information-processing model of memory resembles a computer’s memory system, including temporary and permanent memory.
The Information-Processing View of Memory • The computer has a “buffer” – a temporary
storage place for letters that you type faster than it can display them.
The Information-Processing View of Memory • The computer has RAM, or random-access
memory, for temporary storage of information that has not yet been written to the hard drive. This information is still vulnerable to damage or loss.
• This is analogous to our short-term, or working, memory.
The Information-Processing View of Memory • The computer has a hard drive, in which
information that you are writing or entering can be permanently stored.
The Information-Processing View of Memory • The sensory store
– Although it is probably more accurately
described as a combination of memory and perception, the sensory store is considered to be the first stage of memory processing.
– It is a very brief (less than a second) stage that registers everything that is perceived in the moment that we call “now.”
Figure 7.5
Figure 7.5 George Sperling (1960) flashed arrays like this on a screen for 50 milliseconds. After the display went off, a signal told the viewer which row to recite.
The Information-Processing View of Memory • Short-term and long-term memory
– Temporary storage of information that
someone has just encountered is short-term memory.
– Long-term memory is a relatively permanent storage of mostly meaningful information.
– Reminders or hints that help us to retrieve
information from long-term memory are called retrieval cues.
The Information-Processing View of Memory • Short-term memory
– If a friend asks you what was just said in class, and you were paying attention, you could repeat it, or something close to it.
– This is because you are being asked to recall something from short-term memory.
– If you were not paying attention, you would not recall it. Attention moves information from the sensory store to short-term memory.
Table 7.3
The Information-Processing View of Memory • Long-term memory
– If your psychology instructor asks you to
name the function of the thalamus, your first reaction might be to panic because you have no idea.
– The instructor says, “It has something to do with sensory information, right?”
The Information-Processing View of Memory • Long-term memory
– Then it begins to come back to you – the
thalamus is a relay and integration station for sensory information on its way to the cerebral cortex.
– The instructor gave you a hint that functioned as an effective retrieval cue. These cues can be generated internally or be suggested by others.
The Information-Processing View of Memory • Capacities of short and long-term memory
– Most normal adults can immediately repeat a list of about seven bits or pieces of information, with expected variations in range from five to nine items.
– This “magic range” of 7 +/- 2 bits is a well-replicated finding regarding the capacity of short-term memory.
– It can be expanded through techniques such as chunking into larger, meaningful units.
Figure 7.6
Figure 7.6 We overcome the limits of short-term memory through chunking. You probably could not remember the 26-digit number in (a), but by breaking it up into a series of chunks, you can
The Information-Processing View of Memory • Capacities of short and long-term memory
– The capacity of long-term memory cannot easily be measured.
– Unlike a computer, we are not dealing with a physical limit of size.
– Humans are constantly dumping or removing some of their stored information through
The Information-Processing View of Memory • Decay of short and long-term memory
– Information that has been stored in long-term memory may be vulnerable to the effects of interference, but it generally does not decay due to the effects of time alone.
– Information being held in short-term memory is vulnerable to the effects of the passage of time. – Forgetting tends to begin in seconds unless
Figure 7.9
Figure 7.9 In a study by Peterson and Peterson (1959), people remembered a set of letters well after a short delay, but their memory faded greatly over 20 seconds if they were prevented from rehearsing during that time.
The Information-Processing View of Memory • Capacities of short and long-term memory
– How long information can be held in short-term memory has little relationship to how well it will be stored in long-term memory.
– If the information being held in short-term memory is meaningful, it will be transferred
easily to long-term memory and be less subject to decay.
– This used to be called consolidation - the formation of a long-term memory.
The Information-Processing View of Memory • Capacities of short and long-term memory
– It is now thought that how easily information is consolidated depends on its meaningfulness to the individual. The idea of a distinction
between the short and long-term memory stages may be inaccurate.
– If the information is meaningful, the
groundwork for storing that information has already been done.
The Information-Processing View of Memory • Working memory
– Working memory is a revised concept of the intermediate stage between our first encounter with new information and its eventual storage.
• Working memory is a system for processing or working with current information.
• Working memory is conceptualized as having three major components.
The Information-Processing View of Memory • Working memory’s 3 components:
– A phonological loop that stores and rehearses information, similar to the 7 +/- 2 idea from the traditional concept of short-term memory.
– A visuospatial sketchpad that stores and manipulates visual and spatial information. – A central executive that governs shifts of
attention. Good working memory is able to handle shifts between multiple aspects of complex tasks.
The Information-Processing View of Memory • Other memory distinctions
– A normal type of forgetting is source amnesia. – This involves a combination of episodic and
semantic memory. We remember a statement or knowledge-related (semantic) fact but we forget the context in which we learned it.
The Information-Processing View of Memory • Other memory distinctions
– The context in which one learns information is episodic.
– It can be inferred from the occurrence of this phenomenon that episodic memory is more fragile than semantic knowledge.
Varieties of Memory
• Although there is still much disagreement about the nature of memory, there is general
agreement that memory is not a single store into which we dump the sum of our knowledge and experiences.
Varieties of Memory
• Memory is a complex combination of many processes, and its properties depend on a number of factors
– The type of material memorized
– The individual’s experience with similar materials
– The method of testing
– The length of time since the material was encountered
Video:
Neural Networks
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Video:
Neural Networks
PLAY VIDEO
Module 7.2 • Long Term Memory
Memory Improvement
• To improve memory, one must improve the strategies used to originally store the material.
Meaningful Storage and Levels of Processing • The levels-of-processing principle
– The levels-of-processing principle states that the ease with which we can retrieve a memory depends on the number and types of
associations that we form with that memory • The more ways in which you think about the material, the deeper your processing will be and the more easily you will
Meaningful Storage and Levels of Processing • The levels-of-processing principle
– Ways to think about the material would include asking questions such as:
• Can I think of similar concepts in another subject area?
• How do these apply to me?
• What experiences do I have that are related to this information?
Meaningful Storage and Levels of Processing • The levels-of-processing principle
– To improve your level-of-processing:
• Think about each individual item in a set that you are trying to learn.
• See if you can determine whether or not relationships exist among the items.
Meaningful Storage and Levels of Processing • The levels-of-processing principle
– The levels of processing are:
• Superficial processing – simply repeating the material that you are trying to memorize.
• Deeper processing – think about each item or parts of the material individually.
• Still deeper processing – note the
associations between the items or parts of the material.
Concept Check
Who do you think tends to get better grades in a course, students who read the book quickly or those who read the book slowly?
Concept Check
How would level-of-processing be useful to aspiring actors?
It would help them memorize their lines more effectively.
Timing of Study Sessions
• Because of these effects, the best strategy for anyone who needs to learn a lot of material is to space out the study sessions
– Study the material – Wait for awhile
Use of Special Coding Strategies • Retrieval Cues
– Retrieval cues are bits of associated
information that help you to regain complex memories for later use. Many factors
associated with learning can act as retrieval cues.
Use of Special Coding Strategies • Retrieval Cues
• The encoding specificity principle states that the associations formed at the time of learning are typically the most effective
retrieval cues.
• State-dependent memory is our tendency to remember something better if your
physical condition is the same at the time of recall as it was at the time of learning.
Timing of Study Sessions • The SPAR method
– If you want to remember something for the long-term, study and review it under varying conditions with substantial intervals between sessions
– One systematic way to accomplish this is to use the SPAR method.
The Influence of Emotional Arousal • It is well understood that the greater the
emotional arousal associated with an event, the greater the likelihood that the event will be
remembered.
– Although the event itself may be remembered, the emotion associated with the event does
not guarantee the formation of an accurate memory for the details of the event.
The Influence of Emotional Arousal • During stressful or emotional events, the
sympathetic nervous system works to boost production of the hormones cortisol and
adrenaline.
• This is usually accompanied by increased stimulation of the amygdala.
• The net effect of these processes is to enhance memory storage of information associated with emotional or stressful events.
Concept Check
A Vietnam War veteran who was involved in
several very intense and violent campaigns has been medically monitored for years. He has lower than normal levels of cortisol. How would this
affect his memory?
Concept Check
In order to ace your comprehensive Introductory Psychology final exam, should you immediately review this chapter, or should you schedule some review of the first two or three chapters?
Figure 7.11
Figure 7.11 According to the principle of encoding specificity, how you code a word during original learning determines which cues will remind you of that word later. When you hear the word queen, you may think of that word in any of several ways. If you think of queen bee, then the cue playing card will not remind you of it later. If you think of the queen of England, then chess piece will not be a good reminder.
Use of Special Coding Strategies • Mnemonic devices
– A mnemonic device is any memory aid that is based on encoding each item in a special
way. An example:
• The method of loci uses vivid images of
places, associating each of these locations with something you want to remember.
Figure 7.12
Figure 7.12 A simple mnemonic device is to think of a short story or image that will remind you of what you need to remember. Here you might think of images to help remember functions of different brain areas.
Figure 7.14
Figure 7.14 The method of loci is one of the oldest mnemonic devices. First, learn a list of places, such as my desk, the door of my room, the corridor, . . .” Then link each of these places to an item on a list of words or names, such as a list of the names of Nobel Peace Prize winners.
Improving Our Memory
• We refer to our memories as “stored” and “retrieved” as if they were items on a shelf in a warehouse. But this analogy is only partially useful.
• The more you know about a topic, the more interested you are in it, and the easier it is to establish and retain new information related to the topic.
Module 7.3 • Memory Retrieval and Error
Retrieval and Interference
• There are many plausible reasons to account for the normal forgetting of information
– Interference
– Decay – the memory is subject to the
combined effects of time and interference – Loss of retrieval cues
Interference • Role of interference
– Part of the difficulty for Ebbinghaus may have been the fact that he memorized so many lists of nonsense syllables.
– If an individual learns several sets of related materials, the retention of the old material
makes it harder to retain new material, and the learning of the new materials makes it harder to retain the old.
Interference • The role of interference
– If retaining old material makes it hard to recall new material, it is proactive interference.
– If learning new material makes it hard to recall old material, it is retroactive interference.
– Ebbinghaus had memorized so many lists of nonsense syllabus that he experienced a
Concept Check
You answer the telephone at your new receptionist job with the name of the your former employer’s
firm. What kind of interference caused this embarrassing slip-up?
Reconstructing Past Events
• When you try to remember an event, you usually start with details you remember clearly, and fill in the gaps.
• This is the process of reconstruction. During an event, we construct a memory. When we try to retrieve the memory, we reconstruct an account based partly on surviving memories and partly on expectations of what must have happened.
Reconstructing Past Events
• Your memory for activities that are routine – your breakfast, lunch or dinner for example – from the past week can be reconstructed with little effort. But these will fade rapidly unless something
Reconstructing Past Events
• If your family all got sick after one meal, you will probably remember that meal in better detail for much longer than is usual.
• If you met a new love interest when you were out to dinner with friends, this event will also be more memorable and easily reconstructed.
• However, you may fill in missing details with
typical activities associated in your memory with routine meals at home or dining out.
Reconstructing Past Events
• We will add words to lists that we’ve heard or read depending on what content we believe would have been on the list, based on its
apparent theme.
• The less certain of our memories that we are, the more we will rely on our expectations.
Reconstructing Past Events • Hindsight bias
– Hindsight bias is the tendency to mold our recollection of the past to how events later turned out.
• We say “I knew that was going to happen!” after the event has occurred.
• Our memories are tailored as we
Reconstructing Past Events
• The “false” or “recovered” memory controversy
– Reports of long-lost memories, prompted by clinical techniques, are known as recovered memories.
Often these are memories of abuse that took place in early childhood.
– There have been examples of accurate and
inaccurate memories constructed through clinical techniques.
– Psychological researchers want to know if it is likely that people will forget abusive or traumatic
Reconstructing Past Events • Memory for traumatic events
– Sigmund Freud believed that it was possible to repress a painful memory, motivation or
emotion, to move it from the conscious to the unconscious mind.
– This idea is not well supported in research on memory and forgetting.
Reconstructing Past Events • Memory for traumatic events
– Research indicates that it is possible to forget a traumatic event, but whether this happens depends on a number of factors – age at the time of the event, reaction of family, and type of event.
– Most people do not forget traumatic events if they happen later than age 3.
Reconstructing Past Events
• Memory for traumatic events
– Whether this happens because of repression or normal forgetting is unclear. People forget neutral or joyful events from early childhood as well.
– Repression of traumatic events does not fit with our understanding of the biological process of storing memory.
– Emotional stimulation releases cortisol. The net effect is to improve the storage of memory.
Reconstructing Past Events
• Suggestion and false memory
– A false memory is a report that an individual believes to be a memory but actually never occurred.
• Various studies have shown that it is possible by suggestion to implant memories for fictional
events.
• About a quarter of subjects in several studies were convinced that they had been lost as
Reconstructing Past Events • Suggestion and false memory
– Plausible events were more likely to be remembered, and the memories were
somewhat vague, but these results were achieved after a single, brief suggestion.
– Similarly, memory for details after watching a videotaped event can be altered or distorted by the use of leading questions.
Reconstructing Past Events • Children as eyewitnesses
– Research with children can be ethically difficult because of their vulnerability. – Children forget rapidly and sometimes
confuse fantasy and reality, but sometimes children witness crimes or other events about which we need information.
– How do we work with children to tap their memories accurately? Can we do this?
Reconstructing Past Events • Children as eyewitnesses
– Under proper conditions, children as young as three can make accurate reports of events
that they have witnessed.
• Young children can answer specific questions accurately.
Reconstructing Past Events • Children as eyewitnesses
• A delay between the event and the
questioning is likely to result in the child giving incorrect information.
• If the child can’t understand the question he or she is more likely to give incorrect
Reconstructing Past Events
• Children as eyewitnesses
– Repetition of the question in the same interview session may yield two different answers.
– Repetition of the question between spaced
interview sessions may help the child remember better, which is important in court testimony.
– Dolls and props seem like helpful tools, but they do not increase the accuracy of a child’s recall or testimony.
Reconstructing Past Events • Children as eyewitnesses
– The most effective strategies in interviewing young children are:
• Use of simple questions
• Maintenance of a non-threatening atmosphere during the interview
• Avoidance of suggestions or pressure • Schedule the interview as soon as is
True, False, Maybe
• Memories may or may not be reliable.
• There is much evidence of forgetting and
distortion. We use adaptive strategies for “filling in the gaps” – reason and logic.
• It is prudent to always consider the possibility that a seemingly clear memory is distorted or false.
Module 7.4 • Amnesia
Amnesia After Brain Damage
• Amnesia is a severe loss or deterioration of memory.
• We can learn a lot about the different forms of memory by studying these cases.
Amnesia After Brain Damage • “H.M.”
– In 1953, “H.M.” had his hippocampus and surrounding areas of the temporal lobes removed to control his intractable seizures.
– Although his seizures decreased dramatically, he experienced such severe memory
impairment that the surgeon vowed that he’d never again attempt such a procedure.
Figure 7.19a
Amnesia After Brain Damage • “H.M.”
– He had massive anterograde amnesia. He was unable to store any new memories. (It was 1953 for the rest of his life.)
– He had moderate retrograde amnesia. He
could not remember many events that occurred between 1 and 3 years before his surgery.
– He did retain normal short-term memory functions and procedural memory.
Figure 7.20
Figure 7.20 Brain damage induces retrograde amnesia (loss of old memories) and anterograde amnesia (difficulty storing new memories.)
Amnesia After Brain Damage • “H.M.”
– What has been learned about the
hippocampus from H.M.’s tragic story?
• Other things being equal, the more difficult a memory task is, the more it depends on the proper functioning of the hippocampus. • The hippocampus is important for
Amnesia After Brain Damage • Frontal-lobe damage
– The frontal lobes receive substantial input from the hippocampus. Damage to the frontal lobes causes some problems that are similar to
hippocampal damage, and some unique problems as well.
– Frontal lobe damage occurs as a result of
stroke, head trauma, or Korsakoff’s syndrome, a dementia brought on by deficiency of vitamin B1 related to chronic alcoholism.
Amnesia After Brain Damage • Frontal-lobe damage
– The deficiency leads to loss and shrinkage of neurons in many parts of the brain, especially the thalamus and prefrontal cortex.
– Multiple impairments of memory can result from this deterioration.
Amnesia After Brain Damage • Frontal-lobe damage
– Typical symptoms of Korsakoff’s syndrome include –
• Apathy and confusion
• Retrograde amnesia – usually dating back to about 15 years before the onset of the
syndrome
• Anterograde amnesia
• Confabulation – wild guessing mixed in with correct information in an effort to hide
Amnesia After Brain Damage • Implicit memory in amnesiac patients
– Recall these two divisions of long-term memory:
• Explicit memory involves the recall of
knowledge and events in which a person deliberately retrieves the answer and
recognizes it as a correct one.
–Your instructor asks you to name two psychologists associated with the
Amnesia After Brain Damage • Implicit memory in amnesiac patients
– Implicit memory does not require recognition. The recall of activities stored in implicit
memory seems effortless and unconscious. • You drive your car to school everyday but
don’t remember any details of the activities associated with driving.
Amnesia After Brain Damage • Implicit memory in amnesiac patients
– Amnesiac patients such as H.M. show normal ability to use and store new implicit memory, but have impaired functioning of the factual memory activities of explicit memory.
Amnesia After Brain Damage • Implicit memory in amnesiac patients
– NOR____ – DET____ – COR____ – FRO____
Amnesia After Brain Damage
• Implicit memory in amnesiac patients
– If you wrote any of the following – normal, detail, correct or cortex, frontal, there is a good chance that you were recalling words that appeared in the slides that preceded the task. It will be easy for you to remember this now that you know what
happened.
– Amnesiac patients will perform similarly on this task – called “priming” – they will complete the words in a similar manner, but not remember having read them previously.
Amnesia After Brain Damage • Implicit memory in amnesic patients
– It is not uncommon for such a patient to learn a video game or other procedural task
perfectly. However, the patient will never remember the event of being taught the
game, or any individual session of playing it, even if that patient becomes highly skilled at the actual playing!
Concept Check
You have learned to play the guitar. What type of memory is involved in playing a song for your
friends?
Concept Check
You play guitar at a party for your friends. Later you remember the good time you had playing for them. What type of memory is involved in
remembering this?
Concept Check
• Which of the following is an example of implicit memory?
a. There is a soap opera on TV at home. You don’t get to watch it often, so you can never tell your friends the names of the characters. Two days later you are watching a late night TV
program and you recognize one of the leading men as a guest.
Concept Check
• Which of the following is an example of implicit memory?
• b. You are sitting behind a couple at the movies who are having an animated discussion about
skydiving. You are not paying attention to the content of their discussion. Later you
spontaneously comment to your friends about how much fun it would be to learn to skydive. “ b” is implicit memory
Concept Check
What kinds of memory are most impaired in
frontal lobe dementia patients and patients like H.M.? What kinds are least impaired?
Declarative or explicit memories are most impaired. Procedural or implicit memories are least impaired.
Alzheimer’s Disease
• Most healthy people show little decline of memory in old age
– A common cause of decline in older people
and a few middle aged persons is Alzheimer’s disease.
– About 99% of cases are late onset.
– The disease is marked by a gradual build-up of harmful proteins and deteriorating brain cells.
Alzheimer’s Disease
• Both anterograde and retrograde amnesias result from this build-up
– Arousal and attention are impaired.
– Skills and implicit memory may remain intact for some time.
Amnesia of Old Age
• People would like to know how to increase the chance of having good memory function later in life:
– A healthy lifestyle with regular exercise, good diet, and limited use of alcohol has been
shown to help.
– An intellectually stimulating life may be related to good memory function as well.
Infant Amnesia
• Few people can remember events earlier than age 5 or 6. Though children younger than this can describe earlier events in their own lives, these memories tend to fade.
• The scarcity of early declarative memory is called infant amnesia or childhood amnesia. Why does this happen?
Infant Amnesia
• Freud believed that this was a result of
repression due to the emotional traumas of
infancy. He offered no evidence for this theory. • Some cognitive psychologists believe that this is
because early memories are nonverbal and later memories are verbal.
• A biological explanation is that the hippocampus is not fully developed and doesn’t store
Infant Amnesia
• Another cognitive explanation is that lasting memories require a sense of self, and this
typically doesn’t develop fully until between 3 and 4 years of age.
• The theory of encoding specificity suggests that our retrieval cues in later life may not be
adequate to recall early memories.
• We are still trying to understand why these memories are not accessible.
Amnesia of Old Age
• Some older people suffer from Alzheimer’s and other dementias that impair attention and
memory.
• Up until recently, scientists have typically overstated the vulnerability of healthy older people to memory loss.
Why do we forget?
• Catastrophic loss of memory can only result from brain damage or disease.
• “Normal” forgetting is a product of mechanisms that are usually adaptive.
• It is probably true that remembering everything that happened would be overwhelming and
