Memory Basics: Coding, Capacity, Duration

Ever wondered why you can remember song lyrics but struggle with phone numbers? Baddeley's research shows that your short-term memory (STM) codes information acoustically (by sound), whilst your long-term memory (LTM) codes it semantically (by meaning). This explains why similar-sounding words are harder to remember in the short term.

Your STM capacity is surprisingly limited - Miller's magic number suggests you can hold 7±2 items at once. However, you can boost this through chunking (grouping information together, like remembering a phone number in chunks rather than individual digits).

Duration varies dramatically between memory stores. Peterson and Peterson found STM lasts only 18-30 seconds without rehearsal, whilst Bahrick's yearbook study showed LTM can last decades - participants still recognised 70% of faces after 48 years!

Quick Tip: Use the acoustic nature of STM to your advantage - reading notes aloud can help with immediate recall, but focus on understanding meaning for long-term retention.

Multi-Store Model of Memory

The Multi-Store Model by Atkinson and Shiffrin presents memory as three separate stores working like a factory production line. Information flows from your sensory register (which briefly holds everything you see, hear, smell, taste, and touch) through to STM and finally LTM.

Your sensory register has unlimited capacity but information only lasts half a second unless you pay attention to it. The STM acts like a temporary workspace - limited to 5-9 items for 18-30 seconds. Maintenance rehearsal (repeating information) can keep it active and transfer it to LTM.

The LTM has unlimited capacity and duration, storing information semantically. When you need to remember something, you retrieve it back to STM to use it consciously.

However, this model oversimplifies things. Case studies like KF (who had poor auditory STM but normal visual STM) show that short-term memory isn't just one single store. The model also ignores that elaborative rehearsal (linking to existing knowledge) works better than simple repetition.

Study Smart: Don't just repeat information mindlessly - connect new facts to things you already know for better long-term retention.

Types of Long-Term Memory

Tulving revolutionised memory research by identifying three distinct types of LTM, each serving different purposes in your daily life. This discovery explains why you might lose some memories after brain damage whilst others remain intact.

Episodic memory stores your personal experiences - your first day at college, last weekend's party, or what you had for breakfast. These memories are time-stamped and require conscious effort to recall. They're like your personal autobiography.

Semantic memory contains your general knowledge about the world - knowing that London is England's capital or what the word 'democracy' means. Unlike episodic memories, these aren't linked to when you learned them.

Procedural memory handles your skills and habits - driving, typing, or riding a bike. These are non-declarative, meaning you can perform them without conscious thought. It's why you can change gears whilst thinking about something completely different.

Real-World Application: Understanding these memory types helps explain why stroke patients might forget personal experiences but retain language skills, leading to more targeted rehabilitation programmes.

Working Memory Model

Forget the idea that short-term memory is just one simple store - Baddeley and Hitch's Working Memory Model reveals it's actually a sophisticated system with multiple components working together. This model better explains how you can simultaneously listen to music whilst doing homework.

The central executive acts like your brain's CEO, directing attention and coordinating the other systems. It doesn't store information itself but decides what gets processed where. Think of it as your mental multitasking manager.

The phonological loop handles auditory information through two parts: the phonological store (your 'inner ear') and the articulatory process (your 'inner voice'). It can hold about 2 seconds' worth of speech. The visuo-spatial sketchpad processes visual and spatial information, holding 3-4 objects.

The episodic buffer, added later by Baddeley, integrates information from all sources and links working memory to long-term memory. It's like a temporary mixing desk where different types of information combine.

Study Tip: Use this model to optimise your revision - avoid doing two visual tasks simultaneously (like reading notes whilst watching TV) as they compete for the same resources.

Forgetting: Interference Theory

Why do you sometimes forget information you definitely learned? Interference theory suggests that memories compete with each other, causing forgetting when similar information gets tangled up in your mind. This happens in long-term memory when you can't access information that's actually still there.

Proactive interference occurs when old memories disrupt new ones - like a teacher struggling to learn current students' names because previous years' names keep interfering. Retroactive interference works the opposite way, where new information disrupts old memories.

McGeoch and McDonald's research proved that similarity matters crucially. Participants who learned similar word lists showed the worst recall, whilst those learning completely different material suffered less interference. The more alike the information, the greater the confusion.

However, interference might be less common in real life than lab studies suggest. Tulving and Psotka found that interference effects disappear when proper retrieval cues are provided, suggesting the memories aren't truly lost - just temporarily inaccessible.

Exam Strategy: Space out revision of similar topics (like different psychology theories) rather than cramming them together to reduce interference effects.

Forgetting: Retrieval Failure

Sometimes forgetting isn't about losing information - it's about not having the right key to unlock it. Retrieval failure explains why you might suddenly remember something when you return to where you first learned it or hear a particular song.

Tulving's Encoding Specificity Principle states that retrieval cues must be present both when you learn information and when you try to recall it. These cues become associated with memories during encoding and act like mental bookmarks helping you find the right information later.

Context-dependent cues relate to your external environment - the room, weather, or background noise when learning. State-dependent cues involve your internal state - mood, level of alertness, or even whether you're chewing gum! Research shows that matching these conditions between learning and testing can dramatically improve recall.

This theory has practical applications for improving memory performance. Unlike interference theory, which suggests memories are damaged, retrieval failure implies they're intact but need the right triggers to access them.

Revision Hack: Study in similar conditions to your exam environment, and create strong retrieval cues by using distinctive smells, music, or locations during learning.