1. Chapter 7: Human Memory

2. Human Memory: Basic Questions
How does information get into memory?
How is information maintained in memory?
How is information pulled back out of memory?
Memory is much more than taking in information and putting it in some mental compartment. We have to get it back out, too. Many psychologists study factors that help or hinder memory storage and retrieval, attempting to answer three basic questions:
How does information get into memory?
How is information maintained in memory?
How is information pulled back out of memory?

3. Figure 7.2 Three key processes in memory

4. Encoding: Getting Information Into Memory
The role of attention
Focusing awareness
Divided attention
The first step in getting information into memory is to pay attention to it.
Attention involves focusing awareness on a narrowed range of stimuli or events.
Selective attention is a term used by many psychologists to describe this paying-attention-to-something process; however, the word selective is really redundant. Attention IS selection of input.
Usually, attention is likened to a filter in an information-processing model of memory. The filter screens out most stimuli, while allowing a select few to get by.
Much research has been done to determine whether this filtering process occurs early in the information processing sequence or later.
It appears that both may be at play: sometimes you are paying attention to someone talking with you at a party, and you suddenly hear your name from across the room.

5. Encoding: Getting Information into Memory
The role of attention
Levels of processing
Incoming information processed at different levels
Deeper processing = longer lasting memory codes
Encoding levels:
Structural = shallow
Phonemic = intermediate
Semantic = deep
The first step in getting information into memory is to pay attention to it.
Generally, people need to pay attention to stimuli in order to remember them. Attention involves focusing awareness on a narrowed range of stimuli or events.
According to Craik and Lockhart, whether or not we will be able to remember something depends on how deeply we processed the information.

6. Figure 7.3 Levels-of-processing theory

7. Easier for concrete objects: Dual-coding theory
Enriching Encoding
Elaboration = linking a stimulus to other information at the time of encoding
Thinking of examples
Visual Imagery = creation of visual images to represent words to be remembered
Easier for concrete objects: Dual-coding theory
Elaboration is a process by which a stimulus is linked to other information at the time of encoding. For example, you are studying phobias for your psychology test, and you apply this information to your own fear of spiders.
Elaboration often consists of thinking of examples. Self-generated examples seem to work best.
Visual imagery involves the creation of visual images to represent the words to be remembered. Concrete words are much easier to create images of (example, juggler vs. truth).
Dual-coding theory holds that memory is enhanced by forming semantic or visual codes, since either can lead to recall.

8. Storage: Maintaining Information in Memory
Analogy: information storage in computers ~ information storage in human memory
Information-processing theories
Subdivide memory into three different stores
Sensory, Short-term, Long-term
Plato and Aristotle compared memory to a block of wax that differed in size and hardness for various individuals: remembering was like stamping an impression into the wax.
Today, with technological advances, the analogies have become much more sophisticated.
Atkinson and Shiffrin, 1968, proposed an analogy between information storage by computers and information storage in human memory – the information processing approach.
Basically, this approach divides memory into three different stores: sensory, short-term memory, and long-term memory.

9. Figure 7.6 The Atkinson and Schiffrin model of memory storage

10. Brief preservation of information in original sensory form
Sensory Memory
Brief preservation of information in original sensory form
Auditory/Visual – approximately ¼ second
Sensory Memory is basically information preserved in its original sensory form for a brief time. This type of memory allows the sensation to linger briefly after the sensory stimulation is over: in the visual system, an afterimage.
The visual and auditory sensory stores appear to decay after about ¼ second

11. Short-term or Working Memory
Working or
Short-term
Memory
Sensory
Input
Attention

12. Short-term Memory Function—conscious processing of information
where information is actively worked on
Capacity—limited (holds 7 +/- 2 items)
Duration—brief storage (about 30 seconds)
Working or
Short-term
Memory
Sensory
Input
Attention

13. Maintenance Rehearsal
Mental or verbal repetition of information allows information to remain in working memory longer than the usual 30 seconds
Working or
Short-term
Memory
Sensory
Input
Attention
Maintenance Rehearsal

14. Grouping small bits of information into larger units of information
Chunking
Grouping small bits of information into larger units of information
expands working memory load
Which is easier to remember?

15. Short Term Memory (STM)
Limited duration – about 20 seconds without rehearsal
Rehearsal – the process of repetitively verbalizing or thinking about the information
Limited capacity – magical number 7 plus or minus 2
Chunking – grouping familiar stimuli for storage as a single unit
Short-term memory is defined as a limited-capacity store that can maintain unrehearsed information for up to about 20 seconds.
STM has a limited duration. In other words, information can only be kept there for a brief time before it is lost, unless rehearsal occurs.
Rehearsal is the process of repetitively verbalizing or thinking about the information, keeping it in use.
STM also has limited capacity. George Miller (1956) wrote a famous paper called “The Magical Number Seven, Plus or Minus Two: Some Limits on Our Capacity for Processing Information," where he illustrated that the average person can hold between 5 and 9 chunks of information in STM.
A chunk of information is a group of familiar stimuli stored as a single unit…for example, the following numbers can be thought of as 7 individual numbers or they can be chunked together in groups of 2, 3, etc.

16. Short-Term Memory as “Working Memory”
STM not limited to phonemic encoding
Loss of information not only due to decay
Baddeley (1986) – 3 components of working memory
Phonological rehearsal loop
Visuospatial sketchpad
Executive control system
20 years of research eventually uncovered a number of problems with the original model of STM. STM is not limited to phonemic encoding, as originally thought, and decay is not the only process responsible for loss of information.
These and other findings indicated that STM might be a much more complicated aspect of memory.
Alan Baddeley proposed a more complex model of STM that characterizes it as “working memory,“ with four components.
The phonological rehearsal loop represented ALL of STM in the original model. This component is active when one uses recitation to temporarily hold on to information.
The visuospatial sketchpad allows temporary holding and manipulation of visual images (mentally rearrange the furniture in your bedroom).
The executive control system handles the limited amount of information juggled at one time as people engage in reasoning and decision making: for example at work when you weigh pros and cons of something.
The episodic buffer is a temporary, limited capacity store that allows the various components of working memory to integrate information, and that serves as an interface between working and LTM.

17. Figure 7.7 Short-term memory as working memory

18. Long-term Memory
Once information passes from sensory to working memory, it can be encoded into long-term memory
Long-term
Memory
Working or
Short-term
Sensory
Input
Attention
Encoding
Retrieval
Maintenance Rehearsal

19. Long-Term Memory
Encoding—process that controls movement from working to long-term memory store
Retrieval—process that controls flow of information from long-term to working memory store
Long-term
Memory
Working or
Short-term
Sensory
Input
Attention
Encoding
Retrieval
Maintenance Rehearsal

20. How is knowledge represented and organized in memory?
Long-Term Memory
Unlimited Capacity
Permanent storage?
Flashbulb memories
How is knowledge represented and organized in memory?
Schemas and Scripts
Semantic Networks
Connectionist Networks and PDP Models
While most researchers agree that LTM has an unlimited capacity, that is, our memory store never gets FULL, much debate remains over whether storage is permanent.
Flashbulb memory suggests that LTM is indeed permanent, that the only reason we forget is that we aren’t able to access information that is still in LTM (interference theory). Research shows, however, that flashbulb memories are not always accurate. Is the information still there, or does it decay over time, and we make up for this by building up decayed memories so that they make sense?
Schemas are organized clusters of knowledge about a particular object or event abstracted from previous experience.
A script is a particular type of schema, organizing what a person knows about common activities, for example going to a restaurant. Research shows that people are more likely to remember things that are consistent with their schemas than things that are not. The reverse is also true – people sometimes exhibit better recall if information really clashes with a schema.
Semantic networks consist of nodes representing concepts, joined together by pathways that link related concepts. This explains why thinking of butter makes bread easier to remember.
Connectionist, or parallel distributed processing models, assume that cognitive processes depend on patterns of activation in highly interconnected computational networks that resemble neural networks. This model of memory uses as inspiration the way neurons appear to handle information through connections. According to this model, specific memories correspond to specific patterns of activation in these networks.

21. Types of Long-term Memory
Explicit memory—memory with awareness; information can be consciously recollected; also called declarative memory
Implicit memory—memory without awareness; memory that affects behavior but cannot consciously be recalled; also called nondeclarative memory

23. Procedural Memory
Memory that enables you to perform specific learned skills or habitual responses
Examples:
Riding a bike
Using the stickshift while driving
Tying your shoe laces
Q: Why are these procedural memories implicit?
A: You don’t have to consciously remember the steps involved in these actions to perform them
Try to explain to someone how to tie a shoelace

24. Figure 7.17 Theories of independent memory systems

25. Encoding Specificity
– When conditions of retrieval are similar to conditions of encoding, retrieval is more likely to be successful
– You are more likely to remember things if the conditions under which you recall them are similar to the conditions under which you learned them

26. Flashbulb Memory
The recall of very specific images or details surrounding a vivid, rare, or significant personal event; details may or may not be accurate (e.g., 9/11, wedding day, high school graduation)

27. Retrieval: Getting Information Out of Memory
The tip-of-the-tongue phenomenon – a failure in retrieval
Retrieval cues
Reinstating the context
Context cues
Reconstructing memories
Misinformation effect
Source monitoring
The tip-of-the-tongue phenomenon shows that recall is often guided by partial information about a word—retrieval cues.
Memories can also be reinstated by context cues. It is easier to recall long-forgotten events if you return after a number of years to a place where you used to live.
Memories are reconstructions of the past, which may not be entirely accurate. Research shows that reconstructions can be influenced by new information…the misinformation effect. Elizabeth Loftus has shown that eyewitness testimony can be influenced by information presented to witnesses. Example…showed a video of two cars in an accident…asked some people how fast the cars were going when they HIT each other, asked others how fast the cars were going when the SMASHED INTO each other…a week later asked whether there was any broken glass in the video. The “smashed into” group said yes, the “hit” group said no.
The misinformation effect is explained in part by the unreliability of source monitoring, the process of making attributions about the origins of memories. People make decisions at the time of retrieval about where their memory is coming from: Did I read that somewhere or think of it on my own? Cryptomnesia is inadvertent plagiarism that occurs when you think you came up with it but were really exposed to it earlier.

28. Forgetting: When Memory Lapses
Ebbinghaus’s Forgetting Curve
Retention – the proportion of material retained
Recall
Recognition
Relearning
To study forgetting empirically, psychologists must measure it precisely.
Hermann Ebbinghaus studied forgetting using retention in the late 1800s, by using himself as a subject. He found that retention and forgetting occur over time and plotted his data: the famous forgetting curve. Current research suggests that this curve is unusually steep, probably due to the fact that Ebbinghaus was using nonsense syllables that are difficult to encode semantically.
Retention refers to the proportion of material remembered or retained. Three types of tasks are used to measure retention: (1) recall, which involves requiring subjects to reproduce information on their own without any cues; (2) recognition, which involves requiring subjects to select previously learned material from an array of options; and (3) relearning, which involves requiring subjects to relearn previously learned information to see how much LESS time or effort it takes them.

29. The Forgetting Curve
Hermann Ebbinghaus first began to study forgetting by using nonsense syllables
Nonsense syllables are three-letter combinations that look like words but are meaningless (ROH, KUF)

30. Figure 7.10 Ebbinghaus’ forgetting curve for nonsense syllables

31. Authenticity of repressed memories? Memory illusions Controversy
Why We Forget
Ineffective Encoding
Decay
Interference
Proactive
Retroactive
Retrieval failure
Repression
Authenticity of repressed memories?
Memory illusions
Controversy
Research indicates that forgetting may be related to encoding, storage, or retrieval processes.
Much forgetting may only look like forgetting. It may have never been inserted into memory in the first place—pseudoforgetting—usually due to lack of attention so that encoding does not occur. Ineffective encoding occurs when you encode on a more superficial level than you need to…for example, you are distracted when studying and encode what you are reading on a phonemic rather than a semantic level.
Decay theory proposes that forgetting occurs because memory traces fade with time.
The negative impact of competing information on retention is called interference. Interference theory holds that people forget information because of competition from other material.
Proactive interference occurs when previously learned information interferes with the retention of new information, while retroactive interference occurs when new information impairs the retention for previously learned information.
Why are we able to retrieve a memory on one occasion when we had been unable to recall it previously? The encoding specificity principle holds that the effectiveness of a retrieval cue depends on how well it corresponds to the memory code that represents the stored item. The closer a retrieval cue is to the way we encode the info, the better we are able to remember.
Repression involves the motivated forgetting of painful or unpleasant memories. Recent years have seen a surge of reports of repressed memories of child sexual abuse. The authenticity of these repressed memories is challenged by empirical studies that show that it is not at all hard to create false memories and that many recovered memories are actually the product of suggestion.
Roediger and McDermott (2000) have shown that when participants are asked to learn a list of words, and another target word that is not on the list but is strongly associated with the learned words is presented, the subjects remember the non-presented target word over 50% of the time. On a recognition test, they remember it about 80% of the time: a memory illusion.
While research clearly shows that memories can be created by suggestion, in cases of child sexual abuse memories, for example, this issue becomes quite emotionally charged. Some cases of recovered memories are authentic, and we don’t yet have adequate data to estimate what proportion of recovered memories of abuse are authentic and what proportion are not. Still, this controversy has helped inspire a great deal of research that has increased our understanding of the fallibility and malleability of human memory.

32. Motivated Forgetting Undesired memory is held back from awareness
Suppression—conscious forgetting
Repression—unconscious forgetting (Freudian)

33. Figure 7.11 Effects of interference

34. Figure 7.12 Retroactive and proactive interference

35. Transfer-Appropriate Processing Repression
Retrieval Failure
Encoding Specificity
Transfer-Appropriate Processing
Repression
Authenticity of repressed memories?
Memory illusions
Controversy
According to the encoding specificity principle, sometimes we are unable to retrieve information because the retrieval cues do not correspond very well to memory cues.
Transfer-appropriate processing occurs when the initial processing of information is similar to the kind of processing that is required by the measure of retention. For example, if you memorize a list of words by attending to their meaning, then your memory for these words will be detected better by a measure that asks for semantic recall than by a measure that asks for phonetic recall. Conversely, if you memorized the list by attending to their phonetic properties, then the phonetic measure will show your memory better.
Repression is the motivated forgetting of material, especially anxiety-provoking memories. Recent years have seen a surge in reports of recovered memories. The accuracy of these memories has been sharply debated because experiments show that it is relatively easy to create very real-seeming false memories. Evidence suggests that sometimes therapists have unwittingly produced false memories in their clients, but it is likely that at least some recovered memories are accurate.

36. Figure 7.14 The prevalence of false memories observed by Roediger and McDermott (1995)

37. The Physiology of Memory
Anatomy
Anterograde and Retrograde Amnesia
Hippocampus
Medial temporal lobe memory system
Neural circuitry
Localized neural circuits
Biochemistry
Hormones modulating neurotransmitter systems
Protein synthesis
The anatomy of memory is complex, and many brain structures have been shown to be important in memory. The next slide illustrates the brain structures involved in memory, while the following slide illustrates the two types of amnesia, retrograde (for prior events) and anterograde (for subsequent events). While the role of the hippocampus in memory has long been recognized, many psychologists now view the hippocampus and the surrounding organs as a system, which they call the medial temporal lobe memory system.
From a neural perspective, memories appear to depend on localized neural circuits in the brain. These are reusable pathways in the brain that may be specific for specific memories. Research indicates that long-term potentiation occurs with learning. Long-term potentiation is a long-lasting increase in neural excitability at synapses along a specific neural pathway. This supports the idea that memory traces consist of specific neural circuits.
From a biochemical perspective, research shows that learning causes hormonal changes which may modulate activity in a variety of neurotransmitter systems. Protein synthesis has also been shown to be necessary for memory formation. If you give drugs that interfere with protein synthesis, memory is impaired.

38. Figure 7.16 The anatomy of memory

39. Systems and Types of Memory
Declarative vs. Procedural
Semantic vs. Episodic
Prospective vs. Retrospective
Procedural memory is memory for actions, skills, operations and conditioned responses, and declarative memory is memory for factual information.
Declarative memory can be subdivided into memory for personal facts (episodic) and memory for general facts (semantic).
Retrospective memory is memory for past events, whereas prospective memory is remembering to do things in the future.

40. Gradually Losing the Ability to Remember
Dementia: Progressive deterioration and impairment of memory, reasoning, and other cognitive functions occurring as the result of a disease or a condition
Alzheimer’s disease (AD): A progressive disease that destroys the brain’s neurons, gradually impairing memory, thinking, language, and other cognitive functions, resulting in the complete inability to care for oneself; the most common form of dementia

41. Figure 7.18 Retrospective versus prospective memory

42. Strategies for Boosting Memory
Focus attention
Commit the time
Space study sessions
Organize the information
Elaborate on the material
Use visual imagery
Use a mnemonic device
Explain it to a friend
Reduce interference within a topic
Counteract the serial position effect
Use contextual clues
Sleep on it
Forget the ginkgo biloba