Welcome to Topic B: Cognitive Psychology!
Ever wondered how you can remember the lyrics to a song from five years ago but forget why you walked into the kitchen? That is what Cognitive Psychology is all about! In this chapter, we are going to explore the "inner workings" of the human mind. We treat the brain a bit like a computer: it takes in information (input), processes it, stores it, and then brings it back when needed (output). Let’s dive into how your memory works and how psychologists study it!
1. Models of Memory: How do we store information?
Psychologists use "models" to explain how memory might work. Think of these as blueprints for the mind.
The Multi-Store Model (MSM) – Atkinson and Shiffrin (1968)
This model suggests that memory is made up of three separate stores. Information flows through them in a specific order: Sensory Memory, Short-Term Memory (STM), and Long-Term Memory (LTM).
Encoding: How information is changed so it can be stored (e.g., by sound or image).
Capacity: How much information a store can hold.
Duration: How long the information lasts in that store.
1. Sensory Memory: This is like a "buffer" for your senses. It has a huge capacity but a very short duration (less than a second!). If you don't pay attention, the info is gone.
2. Short-Term Memory (STM): If you pay attention, info moves here. It has a limited capacity (about 7 items) and lasts about 30 seconds. To keep it here, you need to rehearse it (repeat it in your head).
3. Long-Term Memory (LTM): If you rehearse info enough, it moves to LTM. This has an unlimited capacity and can last a lifetime!
Memory Aid: Think of the MSM like a computer. Sensory memory is the keyboard click, STM is the RAM (working area), and LTM is the Hard Drive (permanent storage).
The Working Memory Model (WMM) – Baddeley and Hitch (1974)
The MSM was a bit too simple. Baddeley and Hitch argued that STM isn't just one "waiting room" but a complex mental workspace with different parts:
Central Executive: The "Boss." it drives the whole system and decides which information to pay attention to.
Phonological Loop: The "Inner Ear." It deals with spoken and written material. (e.g., repeating a phone number in your head).
Visuo-Spatial Sketchpad: The "Inner Eye." It handles visual information and where things are in space (e.g., picturing how to walk to your next class).
Episodic Buffer: The "Glue." It brings together information from all other parts and LTM to create a complete "scene" or memory.
Analogy: Imagine an office. The Central Executive is the manager, the Phonological Loop is the telephone, and the Visuo-Spatial Sketchpad is the whiteboard.
Reconstructive Memory – Bartlett (1932)
Bartlett argued that memory isn't like a video recording. Instead, it is reconstructive. When we remember something, we use our schemas to fill in the gaps.
Schemas: Mental "packages" of information based on our past experiences and culture. For example, your "birthday party" schema probably includes cake and presents. If you remember a party, you might "remember" a cake even if there wasn't one, because your schema filled it in!
Key Takeaway: Memory is not perfect storage; it is an active process of rebuilding information based on what we expect to see.
2. Research Methods: How do we test the mind?
Cognitive psychologists love Experiments because they allow for control and show cause-and-effect.
Variables and Hypotheses
Independent Variable (IV): The thing the researcher changes (e.g., whether a student drinks caffeine or not).
Dependent Variable (DV): The thing the researcher measures (e.g., the score on a memory test).
Experimental Hypothesis: A prediction of what will happen. This can be Directional (predicting exactly which group will do better) or Non-directional (predicting there will be a difference but not saying which way).
Null Hypothesis: A prediction that there will be no difference or relationship.
Experimental Designs (The "Who" and "How")
Repeated Measures: Every participant does both conditions of the experiment. (Pro: Needs fewer people. Con: Order effects – people might get bored or better with practice).
Independent Groups: Different people are in each condition. (Pro: No order effects. Con: Participant variables – one group might just be naturally smarter).
Matched Pairs: Participants are paired up based on similarities (like IQ), then split into different groups. (Pro: Best of both worlds, but very hard to do!).
Keeping it Fair: Controls and Validity
Operationalisation: Being very specific about how you define your variables (e.g., instead of saying "memory," say "number of words recalled from a list of 20").
Extraneous Variables: "Nuisance" variables that might mess up your results (like a loud noise outside during a test).
Demand Characteristics: When participants guess what the experiment is about and change their behavior to "help" the researcher.
Quick Review Box:
- Objectivity: Being unbiased and factual.
- Reliability: If you do the study again, do you get the same results?
- Validity: Does the study measure what it claims to measure?
3. Statistics: Making sense of the numbers
Don't worry if this seems tricky! Statistics just help us decide if our results happened by chance or if they are "real."
Levels of Measurement:
1. Nominal: Data in categories (e.g., "Pass" or "Fail").
2. Ordinal: Data that can be ranked or put in order (e.g., 1st, 2nd, and 3rd place).
3. Interval: Data using a fixed scale with equal gaps (e.g., temperature or time).
Probability and Significance:
In Psychology, we usually use the significance level \( p \le 0.05 \). This means there is only a 5% (or less) chance that our results happened by pure luck. If \( p \le 0.05 \), we say our results are statistically significant.
Errors to Avoid:
Type I Error: A "false positive." You think you found something, but you didn't.
Type II Error: A "false negative." You think nothing happened, but there actually was an effect.
4. Key Studies in Cognitive Psychology
Classic Study: Bartlett (1932) "War of the Ghosts"
Bartlett gave British participants a Native American folk tale called "The War of the Ghosts," which contained many unfamiliar concepts. He found that when they retold the story, they changed it to fit their own culture (e.g., changing "hunting seals" to "fishing"). This proved that memory is reconstructive and influenced by schemas.
Contemporary Study: Schmolck et al. (2002)
Schmolck studied patients with brain damage, including the famous patient H.M. (Henry Molaison). They wanted to see if damage to the Hippocampus and surrounding areas affected semantic knowledge (facts). They found that while H.M. could remember many things from his past, he struggled with new semantic information, showing that different parts of the brain handle different types of memory.
The Case of H.M. (Henry Molaison)
H.M. is the most famous patient in psychology history. After surgery to stop seizures, he could no longer form new long-term memories. He could remember things for about 30 seconds (proving his STM worked), but he couldn't "save" them to LTM. Interestingly, he could learn new skills (like drawing), showing that we have different "systems" for facts and skills.
Key Takeaway: Brain-damaged patients help us understand which parts of the brain are responsible for specific memory functions!
5. Practical Investigation: Doing your own experiment
For this topic, you need to design a laboratory experiment using a repeated measures design.
- Goal: Look for a difference in quantitative data (numbers).
- Analysis: Use measures of central tendency (Mean, Median, Mode) and dispersion (Range, Standard Deviation).
- Statistical Test: Use the Wilcoxon signed-ranks test to see if your results are significant.
- Ethics: You must ensure participants are safe, give informed consent, and have the right to withdraw.
Common Mistake to Avoid: Don't forget to define your variables clearly! If you are testing the effect of noise on memory, define "noise" (e.g., loud music at volume 8) and "memory" (e.g., number of words remembered from a list of 15).
Final Summary:
Cognitive Psychology shows us that our minds are busy processors. We use the Multi-Store Model to see the "flow" of memory and the Working Memory Model to see the "workspace." We know from Bartlett that our memories are often "puzzles" we rebuild using schemas. By using scientific experiments and statistics, we can prove these theories and understand how to help people with memory issues.