This week we are covering Chapter 6: Memory. We’ll cover most of the chapter.
Memory processes and stages
Memory can be broken down into 3 basic processes: encoding, storage, and retrieval. How do we encode the information from our senses? How do we store the information? And how do we retrieve/recall that information? If we want to know why we “forget” things, we have to understand how these processes work – and how they don’t work.
The idea that there are different levels of processing (Links to an external site.) let’s us know that not everything is encoded, and so stored and retrieved, the same. The deeper you encode something, the better you will be at remembering it. This is especially helpful when studying – try some of the deep processing techniques (Links to an external site.) like elaborative rehearsal the next time you study for a test and see how much better you do!
There are several models that are useful to consider when studying how memory works. One of the most influential models is the information-processing model (Links to an external site.) (also see video link below). This model likens memory to a computer program which has certain stages and certain processes that move the information back and forth across the stages:
· Sensory memory – holds sensory information for a short period of time
· Attention is required to move information from the sensory memory to short-term memory. Imagine looking at a painting for a 10 seconds, then you are asked to describe what was happening in the upper left-hand quadrant of the painting. Unless you were paying attention to that part of the painting, you might not remember what was there. You probably even looked at it, but you didn’t encode it into your short-term memory because you didn’t pay attention to it.
· Short-term memory (STM) – temporary storage of information (about 30 seconds)
· Maintenance rehearsal is required to move info from your short-term to long-term memory. Imagine I told you my phone number. Unless you repeated it over and over, you will soon forget the number.
· Maintenance rehearsal only works if you are not distracted – if you are also asked to look at a painting and recall it later, you won’t be able to do both and you will forget some parts of the number or painting. This is because your STM is what we call capacity-limited – you can only remember so much at a time.
· George Miller (Links to an external site.) discovered we can only recall 5-9 bits of information, something he called the “ magical number 7 plus or minus 2 (Links to an external site.) ”.
· Chunking (Links to an external site.) is one strategy we use to overcome the limits of STM. (Can we talk about how awesome it is that there is a scientific term called “chunking”?) When you chunk, you group bits of information together so instead of remembering each thing separately, you remember the chunk. Think back to my phone number. My office number is 9542628469. That’s a lot to remember – 9 numbers! But we don’t remember numbers that way, right? We remember the area code (954), then the exchange (it’s an NSU number so it’s 262), then my individual numbers (8469). So really, you only need to remember 6 chunks (or bits) of information (954, 262, 8, 4, 6, and 9), which is well within the “magical number 7 plus or minus 2”.
· There is also working memory (WM) which is different from STM (Figure 6.6). Working memory (Links to an external site.)is used when you are “working” on something in your memory. Think about if I were to ask you to do math in your head: “What is 2 + 2. Add 16. Subtract 10. Multiply by 10. …” You’d be using your WM to accomplish this task.
· The phonological loop works with verbal information. Imagine saying in your head the answer to the math problems given above and then adding/subtracting/multiplying the answer.
· The visuospatial sketchpad works with visual information. Imagine if I asked you to follow directions from your house to a store – you’d envision every left or right I told you to take.
· The episodic buffer brings all the information together.
· The central executive is what directs attention between these 3 processes.
· Long-term memory (LTM) – long-term storage of information
Type of memories
LTM is not one thing. It can be divided broadly into 2 categories, explicit and implicit:
· Explicit memories are those you are aware of and can express in words. Examples include:
· Semantic memories – memory for facts (i.e., a year has 12 months).
· Episodic memories – memory for previous events (i.e., your last birthday).
· Flashbulb memories are those for emotionally significant events (i.e., where were you when you found out about the Marjory Stoneman Douglas school shooting?)
· Implicit memories are those you are not consciously aware of and cannot express in words. Examples include:
· Procedural memories – memories for how to do things (i.e., how you walk or ride a bike).
· Classical conditioning – remember this from last week? A person might not remember why they feel ill whenever they enter the hospital, but they learned this association when they had to come there for a bunch of chemo treatments.
There are many ways that we can improve our memories (Links to an external site.). Infographic 6.1 details some of these ways that you may remember from last week’s topic of learning, including:
· The use of mnemonic devices, method of loci, and hierarchical structures.
· Effortful processing, deep processing, elaborative rehearsal and visualization.
· Distributed practice – don’t just sit down once to study.
· Good sleep hygiene – remember that topic from a few weeks ago?
The way we forget and the things we forget are quite predictable. Herman Ebbinghaus (Links to an external site.) was one of the first people to study memory in a systematic way. He studied lists of nonsense words and measured the number of trials until he remembered them all (remembering curve) and then waited a few days between studying and testing to measure forgetfulness (forgetting curve). Note the forgetting curve here (Links to an external site.) and how it can be mitigated by distributive practice (i.e., spaced learning):
But don’t despair too much! If you have to study something a second time (like if you took psychology in HS and now you’re taking it again), it will take you less time to study it (and remember it) a second time. This is what Ebbinghaus called savings.
He also measured the serial order position effect (Links to an external site.) which examined which words in a list were more or less likely to be remembered (figure 6.9). Both proactive interference (explains recency effect) and retroactive interference (explains primacy effect) contribute to the shape of this curve.
Hollywood loves a good amnesia story! Someone gets hit in the head and BOOM! they can’t remember anything! Of course, truth is stranger than fiction and memory loss / amnesia is not as simple as the movies make it seem. There are many different types of amnesia (memory loss due to physical or psychological trauma):
· Anterograde amnesia – can’t remember things that happened after an injury
· Retrograde amnesia – can’t remember things that happened prior to injury
Stories of amnesia can be heartbreaking, especially if it is a beloved family member who no longer recognizes you. There are a few case studies that although heartbreaking for family members have brought much understanding to the neurobiology of memory and memory loss:
· The chapter starts out talking about Clive Wearing, the man with a 7 second memory. Reading about his case is interesting, but watching him forget things is even more interesting. You can google “Clive Wearing” on YouTube to find a video, orjust check this one out (Links to an external site.) . Can you imagine what life must be like without the ability to remember? Surely, we’d like to forget some things, but imagine not remembering anything?
· Patient H.M. (Links to an external site.) is probably one of the most well-known cases of amnesia. After he underwent a bilateral medial temporal lobectomy (yes, they cut out both sides of his temporal lobe, including his hippocampi and amygdalae), he never again could encode new explicit memories. Interestingly, he could still form new implicit memories. An interview with Suzanne Corkin who studied HM for over 50 years can be read here (Links to an external site.).
Infographic 6.2 in your textbook shows some of the important areas for memory in the brain including (also see Where are memories stored in the brain? (Links to an external site.) From Queensland Brain Institute):
· Hippocampus – explicit memory formation; memory consolidation
· Amygdala – implicit memory and emotion memory
· Cerebellum – implicit memory
· Prefrontal cortex – working memory
· Cerebral cortex – this seems like a really broad area to mention, but memory is distributed throughout the brain
· Temporal lobe – spatial memory storage
· Auditory cortex – auditory memory storage
· Visual cortex – visual memory storage
You might hear people say that someone is “suffering from dementia” and think it just means that they are losing their memory. But dementia is not any one specific disorder. Instead it refers to a group of symptoms that not only involves memory loss, but also disordered thinking, poor problem solving and communication skills, and deteriorating social skills that interfere with a person’s everyday life. Dementia is caused by damage to or loss of neurons and their connections in the brain.
The most common cause of dementia is Alzheimer’s Disease. Alzheimer’s Disease is named after psychiatrist and neuropathologist, Dr. Alois Alzheimer. In 1906, a patient of Dr. Alzhemier’s died. She suffered from an unusual mental illness that included memory loss, unpredictable behavior, and language problems. Along with some of his colleagues, Dr. Alzheimer examined her brain and noticed something odd. Her brain contained clumps of neurons and many neurons were dead or looked damaged by tangled fibers within the neuron itself.
The abnormal clumps that are found in the brains of Alzheimer’s Disease patients are what we now call amyloid plaques. Amyloid is a general term for the bits of proteins that are normally made by the body. Usually, these amyloid bits are broken down and expelled from the body as waste. Sometimes, however, these bits of protein stick around in the areas between neurons and build up, sticking to one another until a clump is formed. These amyloid plaques are not able to be broken down and eventually cause cell death.
The damaged neurons that are found in Alzheimer’s Disease patients are due to neurofibrillary tangles inside the cell. Neurons contain these long tubes called microtubules that help transport nutrients and other substances to all parts of the cell. The microtubule structures are dependent on a group of tau proteins for their shape. In Alzheimer’s Disease, the tau proteins are abnormal and result in the microtubule collapsing. This results in the cell’s eventual death.
While there is no current treatment, scientists are working hard to find ways to slow down or stop diseases like Alzheimer’s Disease. Among the approaches they are studying, scientists are focusing on ways to break up the plaques and to stop the tau proteins from tangling. While far from perfect, there are some treatments that are being used to slow down the progression of some of the memory loss symptoms.
Links with helpful information:
· How Human Memory Works (Links to an external site.) from HowStuffWorks.com
· Video on the Information Processing model (Links to an external site.) from Khan Academy
· Alzheimer’s and dementia (Links to an external site.) from the Alzheimer’s Association
Hit reply and type your answers to the following:
Announcements about upcoming assignments:
· Your stage 1 RWP #2 post is due Sunday, 6/19. Hopefully you have a better idea about this entails since you have completed RWP#1, but let me know if you have questions. This is 10% of your final grade – don’t wait until the last minute.
1. Explain either the information processing model or the working memory model. Be sure to mention the stages and processes of the model and how they work to encode, store, and retrieve information.
2. Give an example of an explicit and implicit memory. Make sure you label what type of explicit and implicit memory you are mentioning.
3. Using Ebbinghaus’ concepts of the forgetting curve, serial order position effect, and savings, how might you tackle studying for your next exam in order to maximize your grade?
4. Using either the case study of Clive Wearing or Patient H.M. answer the following:
· How did the memory loss happen?
· What brain areas were affected and how did that affect the nature of their memory loss?
· What aspects of their memory were spared?
· How does their case contribute to our current understanding of how memory is encoded, stored, and retrieved in the brain?