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Models of Memory

Memory is an extremely difficult subject to study due to its subversive and subjective nature. Thus, many models have been proposed which describe how memories are processed by our brain. The two major ones are the three-box model and the levels of processing model. 

Three-box model

This model of memory is also known as the information-processing model. It describes how the brain processes information (hence the name). Our sensory memory processes external events. Some of that information is encoded by the short-term/working memory. Some of that information is then encoded by the long-term memory. 

Sensory Memory: The sensory memory only lasts for a fraction of a second and consists of the information you are processing right now. George Sperling demonstrated this memory with his experiment, where he would flash a 9 letter grid to subjects for a split second. The subjects were then asked to recall either the top middle or bottom row letters immediately after they appeared. They were able to recite the letters, showing that that information was being stored for a short amount of time. This type of sensory memory is called iconic memory- a short lived photograph of a scene. There is also echoic memory, which is another short lived memory for sounds rather than pictures. Events that are encoded into the working memory are encoded as visual codes (a visual), acoustic codes (a collection of sounds), or semantic codes (the meaning of the event). In order to decide which memories are encoded into the working memory, the brain depends on selective attention. This means that information that is important to us is encoded. This is why we are able to ignore certain stimuli such as the sound of a fan, or the feeling of our clothes because they are not being encoded into the working memory. This is what makes the cocktail party effect work. 

Short-term memory: Short-term memory is known as working memory because they’re the memories we’re working with in the present moment. They last longer than sensory memories, but not very long; usually around 10-30 seconds. Our short-term memory caps at around 7. In his experiments, George Miller found this number, and titled his research “The Magical Number 7, Plus or Minus Two.” So how do we improve the functionality of our short-term memory? One method is through chunking. Take psychology; there’s a lot of vocabulary to memories. If you try and memorise all of those words a couple nights before the exam, you’re not going to have much luck. Instead, it’s better to chunk that massive list into groups of 7. Another example of chunking is the famous mnemonic device; My Very Excellent Mother Just Served Us Nine Pizzas, where the names and order of the planets are chunked into the first letters of each word in the sentence. Another trick is to rehearse the information. Instead of staring at your vocabulary list, repeat the words you’ve chunked to yourself over and over again, thus maintaining that information in your short-term memory.

Long-term memory: These strategies are great for keeping information in our short-term memory, but the best strategies are ones that help encode that information into long-term memory, as it is our permanent storage. So far, it seems that long-term memories storage potential is unlimited. Once information makes it to our long-term memory, it stays- although it is subject to decay. It is stored in three different ways: 

Memories can be explicit of implicit. 

Explicit memories: Also known as declarative memories, these are usually what first come to our mind. They’re conscious memories that we actively try to remember. For example, at the moment, you’re trying to form explicit memories about psychology.

Implicit memories: Also known as non-declarative memories, these are memories we form unintentionally. You may realise when trying to cook lunch that you’ve managed to form an implicit memory on how to cook grandma’s famous pasta because you’ve watched her do it so many times.

An interesting phenomenon involves individuals with eidetic or photographic memory. Alexander Luria studied a patient who could repeat a list of 70 letters backwards, and could remember it as far as 15 years later. 

Levels of Processing Model

Instead of describing memory in steps, this theory maintains that memories are either deeply/elaboratively processed or shallowly/maintenance processed. If to study for an upcoming psychology exam, you repeat a list of vocabulary words to yourself over and over again, you’ve shallowly processed that information, and will go away soon after you’ve taken your test. If you, however study those vocabulary words and do intensive research into each term, you’ve deeply processed those words, and will most likely be able to remember them long after your exam. The more cognitive energy you expend trying to remember something, the longer that memory will last. This model explains why we remember stories and questions better than boring old recitation of events and statements. We find the former more interesting, and more deeply process them.

Retrieval

All memory models end with retrieval. It is the process of taking information out of memory so it can be useful to us. Recognition is a process where we match a fact with one we already have stored in our memory. (”Where have I heard that song?”) Recall is retrieving a memory based on an external cue. (”What did grandma’s pasta taste like?”) There are all kinds of things that change why we’re able to retrieve some memories and why we lose others.

One factor was found by the early psychologist Hermann Ebbinghaus. He found that the order that things are presented in a list influence which things we remember. The primary effect states that we are more likely to remember the first few items on the list, while the recency effect states we are more likely to remember the last few items on that list. Both of these effects come together to form the serial position effect. The serial position effect indicates that we are the least likely to remember words in the middle of a list.

Another factor is context. Something that happens to all of us is the tip-of-the-tongue phenomenon. When I was taking my SAT Biology exam, I completely forgot the word “commensalism.” I sat there thinking facts that I knew about it; it’s a symbiotic relationship, it’s the relationship where one organism is helped and one isn’t hurt or helped” “I watched a youtube video about it” and although I remembered all these facts, it took me a second to remember the actual word. A theory that helps explain why this happens is the semantic network theory. This theory states that our brain forms new memories by joining their meaning and their context with those that already exist in our memory, forming an interlocking web full of memories. So when I was listing facts that I could remember about commensalism, I was making my way through the web, until I finally came across the word. Another phenomenon caused by context are flashbulb memories. When you ask someone who was conscious during 9/11, often they can give detailed descriptions of where they were and what they were doing. This is a flashbulb memory; where the importance causes us to encode more than we normally would.

The emotional context also affects retrieval. Mood-congruent memory is an interesting phenomenon, where you’re more likely to remember something when your mood matches the mood you were in at the time of the event. State-dependent memory is a similar phenomenon, where the state you’re in (for example, drowsy) allows you to retrieve memories from when you were in a similar state.

Constructive Memory

As much as we’d like to believe that it is, memory is not perfect. An example of this is the “recovered memory” phenomenon, where someone seems to “recover” a repressed memory that is actually a false memory based on outside influence. This phenomenon was discovered by Elizabeth Loftus. A constructed memory is a memory that contains false details of a real event, or a fake event altogether. This is why eyewitness accounts can prove to be problematic in police investigations. The way a policeman asks their question can completely change how the eyewitness remembers the event.

Forgetting

A number of things lead to forgetting. One example is decay where memories or connections that we don’t use a lot fade after a while. I used to be able to label every European country when I was younger, but now I’ll be lucky if I can get 15. These memories aren’t gone forever though; the relearning effect has shown that it takes less time recovering these memories than it took the first time. Another thing that causes forgetting is interference. There are two main types: retroactive interference and proactive interference. Retroactive interference is when learning something new hurts your ability to recall older information. Proactive interference is when something you learned a while ago interferes with your ability to learn newer information. A friend of mine told me a fun pneumonic that helps me remember the meaning of these two words: PORN- Proactive, Old interferes with new, Retroactive, New interferes with old.

How Memories are Stored

We know very little about the biological process of memory storage. Research performed on patients with brain damage has shown the hippocampus’ importance in encoding new memories. Patients with a damaged hippocampus had a condition known as anterograde amnesia, where new memories couldn’t form properly, but old memories could be recalled. Think of Dory from finding Nemo. Further connecting to Dory, remember how she could read but couldn’t remember that she could read? Researchers have found this phenomenon typical when studying anterograde amnesiacs, where they can learn and remember new skills but can’t remember learning that skill, showing that procedural memory is stored elsewhere in the brain. When studying memories, researchers tend to focus on long-term potentiation. As neurons fire more and more, their connections can strengthen, making the receiving neuron more sensitive to messages. 

Language

Elements of Language

All languages are built with morphemes and phonemes. Phonemes are the smallest unit of sound in a language. non-English speakers and non-Americans tend to have trouble with the American R- a phoneme that is particularly difficult to recreate. On the flip side, Americans tend to have trouble recreating the Spanish R, while a native Spanish speaker would find that phoneme easy to make. Morphemes are the smallest unit of meaning in a language. Morphemes can be words like “but” and “the” letter like “a” or “I” and prefixes and suffixes like “pre-” and “an-.” Phonemes make up morphemes, and morphemes make up words. The words are organised in a particular order which is known as syntax. Different languages have different syntaxes which can be difficult for non-native speakers to wrap their head around. In english, the order that adjectives are used to describe a word is very particular, and while unconscious for us, is extremely tricky for learners. When describing a dress that you just bought, would you say “my velvet, dinner, new dress? Or would you say “my new velvet dinner dress?” At the same time, in french, the syntax of adjectives can be very frustrating for us to learn. For example, the sentence: Ma ancienne lycée means the high school I formerly attended, while the sentence Ma lycée ancienne means my antique high school. 

Language Acquisition

Studies performed by developmental psychologists have shown that while babies who are learning different languages are developing, they move through the same basic stages. The first step of language acquisition is babbling, and occurs when the baby is typically around 4 months old. Babbling is innate, as shown by the fact that even deaf babies babble. Babbling is a babies way of experimenting with different phonemes, and at this point they can recreate all possible phonemes- this is why teaching a baby or very young child a new language can cause the accent to stick. As the baby continues to develop, the phonemes from its primary languages stick, and they lose the others. Babies will then move from babbling to single words (holophrases) which is aptly names the holophrastic/one-word stage, and normally occurs when the baby is one year old. The next milestone is telegraphic speech or the two-word stage. This typically is around 18 months. Toddlers will smash the words they know into basic commands; “No play!”-  They have meaning down (”I don’t want to play right now!”), but are still working on grammar and syntax rules. As they learn these rules, they tend to misapply them. For example, a toddler may learn that “ed” indicates past tense, and may say “I runned to the store!” This is known as overgeneralisation or overregularisation. 

The specifics of how we acquire language is a bit controversial. Behaviorists think that language is learnt through operant conditioning and shaping. If a baby makes a phoneme that exists in the parents language, or says a word, the parents will smile or pay more attention to the baby, reinforcing that behaviour. Cognitive psychologists challenge this idea. Noam Chomsky stated that humans are born with a language acquisition device. This is known as the nativist theory of language acquisition. He used children who had been deprived of language when they were young to show that there is a critical period for language learning. Today’s psychologists believe it is a combination of these two ideas.

Language and Cognition

How does language influence how we think? I know that personally, my personality changes when I am speaking French versus when I’m speaking English, and I know that I’m not alone. Benjamin Whorf theorised that the language we use affects and limits how we think. This is the linguistic relativity hypothesis. While studies have proven that language effects how we think about people, objects, and ideas, few have shown a drastic change in what we are able to think about.

Thinking and Creativity

Describing Thought

Describing thought is a monumental task; descriptions count as thoughts, so if I can get meta for a moment; we have to use thought to describe thought. It’s immensely difficult to create a global definition of thought, so psychologists tend to describe categories of thoughts instead. Concepts are similar to schemas. Everyone has cognitive rules we use to process our environments, and categorise objects, people, and ideas. We tend to base our concepts on prototypes, or what we think is most typical of a concept. Another kind of thought is an image, a mental picture we have in our mind of the world.

Problem Solving

There are two main kinds of problem solving, and like anything have their drawbacks and their advantages. Say you have a safe to open, and you don’t know the combination. There are two simple ways you can try and open it.

Algorithms: A simple, but arduous way to solve your safe problem is to try every single combination. This is an algorithm and is defined as a rule that guarantees the right solution by using a formula or other foolproof method.

Heuristics: If that safe combination is more than 2 numbers, you could be there all day just punching in numbers. Another thing you could try is using numbers that make up years you know are important to the owner of the safe. This is a heuristic. A heuristic isn’t foolproof and doesn’t guarantee a solution but can seriously shave down the time you spend solving your problem. There are severals of heuristics. Two of the main ones are representative heuristics and availability heuristics.

Heuristics can lead to overconfidence as we overestimate how good our judgements really are. This can lead to belief bias, and belief perseverance. Belief biases are illogical conclusions that we make to confirm preexisting beliefs. Belief perseverance is the tendency to maintain a belief even when evidence proves contradictory.

Impediments to problem solving: 

Rigidity/mental set: The tendency to fall back into comfortable thought patterns. People tend to use problem solving methods that worked in the past to solve a new problem- this can cause people to ignore new solutions. A specific example of rigidity is functional fixedness which is the inability to see a new use for a specific object. Books are for reading, cups are for drinking, and clothes are for wearing. One time I accidentally spilled my tea on my desk, and instead of using the old shirt that was sitting next to my desk, I ran to grab a towel, allowing the tea to get everywhere and nearly ruin my computer. 

Not breaking the problem into parts: Research has proven that by breaking a big problem down into smaller, manageable chunks, tackling the problem is significantly easier and tends to lead to success.

Confirmation bias: When we have made a conclusion about something, when researching it, we tend to ignore research that proves that conclusion wrong. This is why anti-vaxxers can spend hours scouring the internet and pull away one or two studies proving their point right, and completely ignore hundreds of articles that prove them wrong. 

Framing: The way a problem is framed can completely impact our ability to solve that problem. If I were to give you a tricky math problem and tell you “99% of people have solved this problem,” you’d likely go into it not expecting much difficulty, while if I told you “99% of people can’t solve this problem,” you’d likely go in expecting something really difficult. This can completely change how able you are to solve a problem.

Creativity

How do you define creativity? Even harder: how do you find a global definition for creativity? While we may agree on some events exemplifying someone’s creativity, people’s individual criteria for creativity varies massively.

Hi! I'm definitely a weird case bc I vaguely knew what I wanted to do going into uni and only switched majors once BUT i do know ppl who made dramatic changes or many small adjustments once they got to uni and it's absolutely okay!!

Depends on how uni in your country is designed but here in the US you have the option to be undeclared (i.e. exploring majors and not committing to one) or switch majors up to a certain amount of credit hours.

My suggestions are:

see if your interests converge. do you like your science classes, like helping others, and find random pimple popping videos on youtube interesting? maybe you'd like taking chemistry, health, anatomy, and forensic anthropology. or maybe you're into historical events, are a feminist, and like movies. maybe you could take gender studies with a focus on the feminist movement and feminist media! where these interests meet is where you'll find a passion. (for reference, i like science, helping others, public health, and lab work)

look at experiences outside of the classroom to determine your interests too! just bc you got an A in a subject in HS doesn't always mean you enjoyed it. maybe you got a D in physics but you really loved the logistics behind the NASA SpaceX launch!

go through your future uni (or a community college/uni close to you if you don't know where you're headed yet)'s course catalog/class schedule. pick out classes that interest you in the slightest. see which ones of those you could take your first term to help lead you down a path! my first term i took a nutritional anthropology class even though i knew nothing about it except that it seemed interesting and now I've taken 3 anthropology classes and enjoyed them! My friend enjoyed them so much she's getting an anthro minor!

remember you don't have to choose now.

if all else fails, the classes you take during your exploration can be used towards: general education requirements, electives, minors, etc. so don't worry too much so long as you're on track to graduate!

finally, some content! this was a quick info graphic I drew up on Procreate to revise for my ochem test tomorrow. disclaimer: I used information from this source (https://www.masterorganicchemistry.com/2010/05/24/imines-and-enamines/) since my own notes are based off lectures I received at my university that I’m not really allowed to share without heavy modification.

general post disclaimer: I’m an undergraduate student studying biochemistry and genetics. Posts are made for the purposes of education, revision and aesthetics. Not all the content I produce can be taken as entirely accurate and I do not take responsibility for errors made as a result of using this resource. Always consult course textbooks and lectures to aid in your specific learning outcomes. Do not repost without the original caption citing any extra references I used to make this post or remove my watermark. Other posts can be found on my blog [email protected]. Any problems, feel free to get in touch via my messages.

Time for some pre lecture reading like the "good" student I am.

2.4.2019