🗓 Unit 8
Memory

PSYC 181 – Intro to Psych

Emma Marshall – Instructor

University of Nebraska-Lincoln

July 31, 2024

What you will learn

Learning Objectives

• Define and describe the three phases of memory
• Explain how we encode new information
• Describe how we store memories over time
• Recognize memory failures and discuss the underlying mechanisms and processes

The study of memory looks at some of the following questions: - How do we process and store information? - Are there different types of memory? - How do we retrieve memories? - Why do we forget?

What is memory?

Capacity to retain and retrieve skills and knowledge

Experience

Process

System

Neural

Flawed

HOW MEMORY FUNCTIONS

Memory is an information processing system like a computer. It is a set of processes used to encode, store and retrieve information over different periods of time.

• Encoding involves the input of information into the memory system.
• Storage is the retention of the encoded information.
• Retrieval, is getting the information out of memory and back into awareness.

PARTS OF THE BRAIN INVOLVED IN MEMORY

Amygdala involved in fear and fear memories (memory storage is influenced by stress hormones)

Hippocampus associated with explicit memory, recognition memory and spatial memory

Patient H.M had both temporal lobes removed (including hippocami) to help control his seizures

Cerebellum plays a role in processing procedural memories

• Damage prevents classical conditioning

Prefrontal cortex appears to be involved in remembering semantic tasks

• Encoding ➜ left frontal activity
• Retrieval of information ➜ right frontal activity

Scientists have now identified different parts of the brain involved in memory.

Amygdala- Processes emotional information important in encoding memories at a deeper level and memory consolidation.

Hippocampus- Projects information to cortical regions that give memories meaning and connect them with other memories. - Involved in memory consolidation. - Damage leads to an inability to process new declarative memories.

Cerebellum- plays a role in processing procedural memories, such as how to play the piano and classical conditioning. Damage prevents classical conditioning - such as an eye-blink in response to a puff of air.

Prefrontal cortex: - PET scans show activation in the left inferior prefrontal cortex when completing semantic tasks. - Encoding is associated with left frontal activity. - Retrieval of information is associated with the right frontal region.

NEUROTRANSMITTERS

Memory Consolidation Repeated neuron activity ➜ increased neurotransmitters in the synapse ➜ stronger synaptic connections

Neurotransmitters

Epinephrine

Dopamine

Serotonin

Glutamate

Acetylcholine

Arousal Theory strong emotions trigger the formation of strong memories and weaker emotional experiences form weaker memories

Communication among neurons via neurotransmitters is critical for developing new memories.

• Strong emotional experiences can trigger the release of neurotransmitters which strengthen memory.
• Evidenced by flashbulb memories - an exceptionally clear recollection of an important emotional event.

FLASH BULB MEMORY

Flash bulb memory a record of an atypical and unusual event that has very strong emotional associations

Depending on the age and awareness/interests of the person, certain flashbulb memories can act as generational reference points. Examples include: - The assassinations of President John F. Kennedy, Martin Luther King Jr., Malcolm X, or Robert Kennedy. - The first humans landing on the Moon - The attacks of September 11, 2001

Flashbulb memory formation may depend on cultural reference and personal investment/involvement. - A national leader suddenly resigning may become a flashbulb memory for those citizens only. - An athlete suddenly retiring may become a flashbulb memory for fans of that sport or team.

9/11 is the most recent flashbulb memory that has been extensively researched.

AMNESIA

Amnesia loss of long-term memory that occurs as the result of disease, physical trauma, or psychological trauma

There are 2 common types: 1. Anterograde amnesia – inability to remember new information after point of trauma. - Commonly caused by brain trauma. - Hippocampus is usually affected – causes inability to transfer information from STM to LTM. 2. Retrograde amnesia – loss of memory (partial or complete) for events that occurred prior to the trauma

ENCODING

When you first learn new skills such as driving a car, you have to put forth effort and attention to encode information about driving. Once you know how to drive, you can encode additional information about this skill automatically. (credit: Robert Couse-Baker)

Brain receives inputs from environment and…

• Labels/codes it
• Organizes it with other similar information
• Connects new concepts to existing concepts

Automatic processing: encoding of details like time, space, frequency, and the meaning of words

• Usually done without conscious awareness

Effortful processing encoding of details that takes time and effort

TYPES OF ENCODING

Semantic encoding encoding of words and their meanings

• attach meaning to facilitate recall (most effective)
• Involves a deeper level of processing

Visual encoding encoding of images

• (concrete) words that create a mental image easier to recall than (abstract) words

TYPES OF ENCODING

Acoustic encoding encoding of sounds

Self-reference effect tendency to have better memory for information that relates to oneself

1. Semantic encoding encoding of words and their meanings

   • attach meaning to facilitate recall (most effective)
   • Involves a deeper level of processing

2. Visual encoding encoding of images

   • Words that create a mental image, such as car, dog and book (concrete words) are easier to recall than words such as level, truth and value (abstract words).

3. Acoustic encoding – encoding of sounds.

4. Self-reference effect – the tendency for an individual to have better memory for information that relates to oneself in comparison to material that has less personal relevance.

Atkinson-Shiffrin Model of Memory

Storage creation of a permanent record of information

Atkinson-Shiffrin Model of Memory: - Information passes through three distinct stages in order for it to be stored in long-term memory. - Based on the belief that memories are processed the same way that a computer processes information.

Sensory memory – storage of brief sensory events, such as sights, sounds, and tastes. - Stored for up to a couple of seconds. - First step of processing stimuli from the environment. - If the information is not important, it is discarded. - If the information is valuable then it moves into our short-term memory. In the middle of the 20th century, many scientists were interested in short-term memory (STM), or how humans can hold small amounts of information actively in their minds for a short period of time. Atkinson & Shiffrin (1968) wrote a landmark paper that synthesized existing evidence on how memory functions and proposed a model of memory referred to as the Modal Model of Memory (4.1). In this model, information first enters sensory memory, which is a highly transient storage space for information that recently entered your sensory system. This information is high quality but fades away very quickly. Have you ever had the experience of hearing someone say something when you weren’t really paying attention, then repeating it immediately in your head, and then being able to understand it? For about three seconds, you can play back the auditory information that you just heard. You can even hear it in the speaker’s original tone of voice! You use your sensory memory to do this.

The next stage the Modal Model is short-term memory. Information that you pay attention to from sensory memory enters the short-term memory store. As the name suggests, information is retained in the Short Term Memory for a rather short period of time (15–30 seconds). In order to keep information in short-term memory, the model suggests you must rehearse it.

How much information can be held in short-term memory? According to George Miller (1959), the capacity of short-term memory is five to nine pieces of information (The magical number seven, plus or minus two). That’s why I could read a 7-digit phone number to you and have you repeat it back, but if I read you my 16-digit credit card number and asked you to repeat it to me, it would probably feel impossible. What counts as a “piece of information?” A piece of information is called a chunk, which is a meaningful unit of information. All of the following can be chunks: single digits or letters, whole words, or even sentences. An example of chunking information is the following.

Try to remember the following digits:

1 2 2 5 1 9 8 4

Now try to remember the same digits, but group them differently:

12 - 25 - 1984

With this strategy you chunked eight pieces of information (eight digits) to three pieces to remember them as a date on the calendar. You could chunk the information even more efficiently if you recognize 12-25 as a single unit, the date of Christmas. The process of chunking is the process of combining smaller units of information into larger, meaningful units of information. The term “meaningful” is subjective— a meaningful chunk for you might not be a meaningful chunk for me. For example, 3 5 3 1 might not make a meaningful chunk for everyone, but if you’re a student of football history, you might chunk it as 35–31: the final score of the Super Bowl XIII, when Jackie Smith dropped a touchdown pass in the end zone.

A famous experiment concerned with chunking was conducted by Chase & Simon (1973) with novices and experts in chess playing. When asked to remember certain arrangements of chess pieces on a board, the experts performed significantly better that the novices. However, if the pieces were arranged randomly, i.e. not corresponding to possible game situations, both the experts and the novices performed equally poorly. The reason is that expert chess players spend hours studying chess games and memorizing board configurations. When trying to remember the layout of a chess board, the experienced chess players do not try to remember single positions of the figures in the correct game situation, but whole chunks of figures from their memory. In random board configurations this strategy cannot work, which shows that chunking (as done by experienced chess players) enhances the performance only in specific memory tasks.

Left: A chessboard in the middle of a real game. Right: A random arrangement of chess pieces. Chess experts have significantly better memory for real boards, but perform more like novices for random board configurations. Figure 4.2: Left: A chessboard in the middle of a real game. Right: A random arrangement of chess pieces. Chess experts have significantly better memory for real boards, but perform more like novices for random board configurations.

The third stage of the Modal Model is long-term memory. According to the Modal Model, the important processes for long-term memory are storage (i.e., transferring information from short-term to long-term memory), search (i.e., locating information in the long-term store) and retrieval (i.e., recovering the information from the long-term store)

THE STROOP EFFECT

Blue

Green

Black

Green

Red

Green

Black

Green

Green

Blue

Green

Black

Green

Black

Red

Blue

The Stroop effect was discovered while studying sensory memory and describes why it is difficult for us to name a color when the word and the color of the word are different.

BADDELEY & HITCH MODEL

Baddeley and Hitch proposed a model of storage where short-term memory has different forms depending on the type of information received.

Storing memories is like opening different files on a computer and adding information.

Three short-term systems 1. Visuospatial sketchpad 2. Episodic buffer 3. Phonological loop According to the model, a central executive supervises the flow of information between the systems.

Atkinson & Shiffrin (1968) formulated the Modal Model as a foundational framework to guide researchers in developing memory models (Wixted, 2024). Beyond the simple model, they depicted the short-term store as the central hub of memory activity, one that involved both verbal and visual stores (Atkinson & Shiffrin, 1968, 1971). Building on these ideas, Baddeley & Hitch (1974) proposed their Working Memory Model. While the Modal Model was relatively focused on the memory function of the short-term store, Baddeley and Hitch described a working memory as chiefly an information processing system. Notice the difference in terminology: Atkinson and Shiffrin called the temporary memory space “short-term memory” while Baddeley and Hitch use the term “working memory.” Atkinson and Shiffrin would not dispute this terminology – indeed, the first page of their introduction says “the short-term store is the subject’s working memory” (Atkinson & Shiffrin, 1968, p. 90) – though it has become a common misconception that their 1968 paper asserts that short-term memory is limited to simple storage (Wixted, 2024). Today, scientists may still use the term “short-term memory” when discussing the temporary storage of simple items, but “working memory” has become the preferred term, emphasizing the role of the system in complex cognition.

According to Baddeley, working memory is capable of both storage and manipulation of incoming information. Baddeley and Hitch’s 1974 model consists of three parts: two storage spaces called the phonological loop and the visuospatial sketch pad, and a control unit called the central executive.

We will consider each part in turn: The phonological loop is responsible for auditory and verbal information, such as phone numbers, people’s names, or general conversation. One source of evidence that we have a special storage space for auditory information is the phonological similarity effect. Read the following list of words, then look away and try to repeat it to yourself:

car rig seam bar rose pop gear

And now try this one:

leak feed beak deep heat peek beat

If you are like the participants in a study by Conrad (1964), your performance was worse on the second list than it was in the first. The reason the second list was harder is because when you read the words on the page, you translate them into an acoustic form. Because the words in the second list sound alike, you are more likely to confuse them as you repeat them in your phonological loop.

How much information can the phonological loop hold? Researchers have found that the magical number seven plus or minus two does not explain all of the available data. While Miller’s magical number is approximately accurate when English-speaking participants remember digits or letters, it doesn’t hold when the length of the words is manipulated.

To demonstrate this to yourself, try to remember the following list of words:

lip base rain duck bib fall gate

And now try this one:

carpenter radiate thermostat honesty photograph dinosaur horizon

Both lists are seven words long, and yet people are much worse at a list like the second one (Baddeley et al., 1975). This is called the word-length effect: lists of short words are recalled better than lists of long words. If you think back to early research on short-term memory, this result is surprising! According to Miller’s magical number, these lists should be remembered equally well because they contain the same number of items. Findings like the word length effect led researchers to conclude that the capacity of the phonological loop should not be measured in number of items, but in amount of time instead: the phonological loop can hold about two seconds of auditory information, which it can replay over and again through an active articulatory process. Imagine you have two seconds of tape— you could fit a lot more short words on it than long words!

The next component of working memory is the visuospatial sketch pad, which handles visual and spatial information. Like the phonological loop, the visuospatial sketch pad is primarily a storage space. What evidence do we have that visual and spatial information is stored independently from auditory and verbal information? Look at the block letter F to the right. In an example experiment, you would be instructed to memorize the letter, and then, starting with the starred corner and then traveling up and around the letter, indicate whether each corner is an outside corner (like the starred corner) or an inside corner (like the fifth corner as you travel around the shape). In one condition, participants would verbally say “outside” or “inside” for each corner. In the other condition, participants would point at the words “outside” and “inside” displayed in front of them for each corner. Brooks (1968) conducted an experiment similar to this one, and found that participants were much better at the task when they could verbally indicate the type of corner than when they had to point. Why? We have two storage spaces in working memory and each of them is limited in capacity. Mentally traveling around the block letter and judging the corners is a spatial task, and so it puts a load on the visuospatial sketch pad. If you add pointing on top of that, participants’ visuospatial sketch pads get overloaded and they struggle to do both simultaneously. If instead you allow participants to respond verbally, they are distributing the response aspect of the task onto the phonological loop. That way, neither storage system becomes overloaded.

We have seen that the phonological loop and the visuospatial sketch pad deal with different kinds of information, which nonetheless have to interact in order to do certain tasks. The component that connects these two systems is the central executive. The central executive coordinates the activity of both the phonological loop and the visuospatial sketch pad. In fact, most of the “working” part of working memory is done by the central executive.

The functions of the central executive can be broken down into three categories: shifting, updating, and inhibition (Miyake et al., 2000). Shifting refers to engaging and disengaging from tasks, such as switching your attention back and forth between watching television and doing the dishes. Updating refers to monitoring information that is incoming into working memory, and making room for it by replacing old information in working memory. Inhibition refers to the deliberate inhibition of responses, such as when the ticket taker says “enjoy your movie!” and you stop yourself from saying, “you too!”

The episodic buffer Science is an ongoing process, and so despite the usefulness of Baddeley and Hitch’s working memory model, it was updated in 2000 to add another component: the episodic buffer (Baddeley, 2000). The episodic buffer is a limited capacity, temporary storage system that is controlled by the central executive and integrates information from a variety of sources including long-term memory. The episodic buffer was added to help account for human performance in complex cognition— for example, we can remember many more words when we remember a meaningful sentence than when we remember a random word list. The episodic buffer was added to help account for this and other phenomena in which working memory performance seemingly requires additional storage as well as interfacing with long-term memory. The addition of the Episodic Buffer paralleled broader movement in the field towards thinking about how knowledge impacts working memory capacity.

SHORT-TERM Working MEMORY

Working memory a temporary storage system that processes incoming sensory memory

• Lasts about 20 seconds
• Capacity is usually about 7 items +/- 2
• Either discarded or stored in long-term memory

RECALL EXERCISE: Read each string of numbers out loud and have student write down what they can remember after each string to determine longest string of numbers they can remember.

9754, 68259, 913825, 5316842, 86951372, 719384273

6419, 67148, 648327, 5963827, 51739826, 163875942

Chunking

Chase & Simon (1973)

A famous experiment concerned with chunking was conducted by Chase & Simon (1973) with novices and experts in chess playing. When asked to remember certain arrangements of chess pieces on a board, the experts performed significantly better that the novices. However, if the pieces were arranged randomly, i.e. not corresponding to possible game situations, both the experts and the novices performed equally poorly. The reason is that expert chess players spend hours studying chess games and memorizing board configurations. When trying to remember the layout of a chess board, the experienced chess players do not try to remember single positions of the figures in the correct game situation, but whole chunks of figures from their memory. In random board configurations this strategy cannot work, which shows that chunking (as done by experienced chess players) enhances the performance only in specific memory tasks.

Figure 4.2: Left: A chessboard in the middle of a real game. Right: A random arrangement of chess pieces. Chess experts have significantly better memory for real boards, but perform more like novices for random board configurations.

LONG-TERM MEMORY (LTM)

LTM is the continuous storage of information. - It has no limit and is like the information you store on the hard drive of a computer. - There are two components of long-term memory: explicit and implicit.

LTM: EXPLICIT MEMORY

Explicit memory memories of facts and events we can consciously remember and recall/declare

Explicit memories include two types: 1. Semantic – knowledge about words, concepts and language. - Knowing who the President is. 2. Episodic – information about events we have personally experienced. - Remembering your 5th birthday party. - The what, where, when of an event. - Also called autobiographical memory.

A small number of people (including actress Marilu Henner) have a highly superior autobigraphical memory known as hyperthymesia.

LTM: IMPLICIT MEMORIES

Implicit memory memories not part of our consciousness

• Formed through behaviors. - Procedural – stores information about how to do things. - Skills and actions. - E.g. how to ride a bike, tie your shoe laces, drive.

Implicit memory also includes behaviors learned through emotional conditioning. - You might have a fear of spiders but not consciously remember why or what occurred to condition that fear.

RETRIEVAL

How to you get information back out of storage?

Retrieval – the act of getting information out of memory storage and back into conscious awareness. - Retrieval is needed for everyday functioning (e.g. knowing how to drive to work, or how perform your job once you get there).

3 ways to retrieve information: 1. Recall – being able to access information without cues. - Used for an essay test. 2. Recognition – being able to identify information that you have previously learned after encountering it again. - Used for a multiple choice test. 3. Relearning – Learning information that you previously learned. - After learning Spanish in high school, you might forget how to speak it if you do not use it. However, if you try to relearn it, you will learn it quicker than the first time.

MEMORY CONSTRUCTION & RECONSTRUCTION

Construction formulation of new memories

Reconstruction process of bringing up old memories

When we retrieve memories, we tend to unintentionally alter and modify them, resulting in inaccuracies and distortions.

Memory consolidation – Transfer of STM to long-term memory. - One way memory consolidation can be achieved is through rehearsal. - Rehearsal – the conscious repetition of information to be remembered.

Eyewitness Memory

Wells et al (1998)

Suggestibility

Suggestibility is the effects of misinformation from external sources that leads to the creation of false memories. - Can cause people to claim to remember something that was only a suggestion someone made. - Memories are fragile making them vulnerable to the power of suggestion. - An important area of study has been the role of suggestibility in eyewitness testimonies.

Eyewitness Lineup

EYEWITNESS MISIDENTIFICATION

In studying cases where DNA evidence has exonerated people from crimes, the Innocence Project discovered that eyewitness misidentification is the leading cause of wrongful convictions (Benjamin N. Cardozo School of Law, Yeshiva University, 2009).

Eyewitness identification and testimony is often used in the prosecution of criminals.

Research suggests that suggestive police identification procedures can lead to alterations in an eyewitnesses memory leading to misidentification.

THE MISINFORMATION EFFECT

Loftus & Palmer (1974)

When people are asked leading questions about an event, their memory of the event may be altered

Elizabeth Loftus: - Studied false memories. - Misinformation effect paradigm – after exposure to incorrect information, a person may misremember the original event.

Study (1974): - Asked college students to estimate the speed of cars using different forms of questions. - Participants were shown films of car accidents and were asked to play the tole of eyewitness and describe what happened. - Were asked, “About how fast were the cars going when they (smashed, collided, bumped, hit, contacted) each other?” - Participants that heard the word smashed estimated that the cars were travelling a lot faster than those that heard the word contacted. - If they heard the word glass, they were more than twice as likely to say they remember seeing glass (a false memory). - The implied meaning of the word used influenced the participants memory of the accident.

Loftus on Memory

REPRESSED & RECOVERED MEMORIES

False memory syndrome recall of false autobiographical memories

Repressed memories some psychologists believe can completely repress traumatic childhood memories

But Loftus does not agree!

A controversial topic within psychology is the idea that whole events can be repressed or falsely recalled.

such as sexual abuse - Can lead to psychological distress in adulthood - Some believe that these can be recalled through hypnosis and guided imagery techniques

Loftus challenges the idea of repressed memories and questions if recalled memories are accurate or whether the processes of questioning and suggestibility leads to the misinformation effect.

How can suggestibility be avoided when questioning eyewitnesses?

WHY DO WE FORGET?

Forgetting loss of information from long-term memory

Encoding Failure occurs when the memory is never stored in the first place

• Successful encoding requires effort and attention
• Can you tell which coin is the accurate depiction of a US nickel? - Most American’s cannot tell which one because we do not encode the specific details, we just know enough to differentiate it from other coins.

Mandella Effect

Rasad & Bainbridge (2022)

The Mandela effect is an Internet phenomenon describing shared and consistent false memories for specific icons in popular culture. The visual Mandela effect is a Mandela effect specific to visual icons (e.g., the Monopoly Man is falsely remembered as having a monocle) and has not yet been empirically quantified or tested. In Experiment 1 (N = 100 adults), we demonstrated that certain images from popular iconography elicit consistent, specific false memories. In Experiment 2 (N = 60 adults), using eye-tracking-like methods, we found no attentional or visual differences that drive this phenomenon. There is no clear difference in the natural visual experience of these images (Experiment 3), and these errors also occur spontaneously during recall (Experiment 4; N = 50 adults). These results demonstrate that there are certain images for which people consistently make the same false-memory error, despite the majority of visual experience being the canonical image.

Rasad & Bainbridge (2022)

MEMORY ERRORS: Schacter’s 7 sins of memory

Forgetting type

1. Transience accessibility of memory decreases over time (storage decay)

2. Absentmindedness forgetting caused by lapses in attention

3. Blocking accessibility of information is temporarily blocked (aka tip-of-the-tongue phenomenon)

Distortion type

4. Misattribution source of memory is confused

5. Suggestibility false memories

6. Bias memories distorted by current belief system

Intrusion type

7. Persistence inability to forget undesirable memories

TRANSIENCE/STORAGE DECAY

Overtime, unused information tends to fade away.

Ebbinghaus (1885) showed how quickly memory for new information decays

• 50% after 20 minutes
• 70% after 24 hours

Studied the process of memorization.

Memory BIASES

According to Schacter, your feelings and view of the world can distort your memory of past events.

Stereotypical bias after presenting people with a list of names, they more frequently incorrectly remembered typical African American names to be associated with the occupation basketball player, and typical white names to be associated with the occupation politician

Egocentric bias people remember events in a way that makes them look better

Hindsight bias the tendency to think you knew the answer all along

Example: How many neck bones does a giraffe have? Answer: Seven

Blank, H., & Nestler, S. (2007); Bernstein et al. (2011)

Blank, H., & Nestler, S. (2007); Bernstein et al. (2011)

PERSISTENCE

Many veterans of military conflicts involuntarily recall unwanted, unpleasant memories. (credit: Department of Defense photo by U.S. Air Force Tech. Sgt. Michael R. Holzworth)

INTERFERENCE

Sometimes forgetting is caused by a failure to retrieve information. This can be due to interference, either retroactive or proactive.

WAYS TO ENHANCE MEMORY

Rehearsal conscious repetition of information to be remembered

Chunking organizing information into manageable bits or chunks

Elaborative rehearsal technique in which you think about the meaning of the new information and its relation to knowledge already stored in your memory

Mnemonic device memory aids that help us organize information for encoding

Other techniques can include: - Expressive writing. - Saying words aloud.

MNEMONIC DEVICES

This is a knuckle mnemonic to help you remember the number of days in each month. Months with 31days are represented by the protruding knuckles and shorter months fall in the spots between knuckles. (credit: modification of work by Cory Zanker)

HOW TO STUDY EFFECTIVELY

Memory techniques can be useful when studying for class.

1. Use elaborative rehearsal: link information to other information/memories to make it more meaningful.
2. Apply the self-reference effect: make information personally meaningful to YOU
3. Don’t forget the forgetting curve: keep studying to prevent storage decay.
4. Rehearse
5. Be aware of interference: study without distractions.
6. Keep moving: aerobic exercise promotes neurogenesis (growth of new brain cells in the hippocampus).
7. Get enough sleep: the brain consolidates memories while sleeping
8. Make use of mnemonic devices!!