Welcome to Cognitive Psychology!

In this chapter, we are going to explore the "inner workings" of the human mind. Think of your brain as a super-powerful computer. Cognitive Psychology is all about how that computer processes information—how we take it in, store it, and use it later. We will focus mostly on Memory: how it works, why it sometimes fails us, and how it changes as we grow older. Don't worry if it seems like a lot to take in; we'll break it down bit by bit!


1. Models of Memory

Psychologists use "models" to explain how memory works. Think of these like maps that show how information travels through your mind.

The Multi-Store Model (Atkinson and Shiffrin, 1968)

This model suggests that memory is made up of three separate "stores." Information flows through them in a fixed order.

  • Sensory Memory: This is the "waiting room." It takes in everything from your senses (sights, sounds). It has a huge capacity but a very short duration (less than a second!). If you don't pay attention, the info is gone.
  • Short-Term Memory (STM): If you pay attention, info moves here. It can hold about 5 to 9 items (7 plus or minus 2). It lasts about 15–30 seconds. We encode (process) information here mainly acoustically (by sound).
  • Long-Term Memory (LTM): If you rehearse information (repeat it), it moves to LTM. This has an unlimited capacity and can last a lifetime! We mainly encode info here semantically (by meaning).

Memory Aid: Use the mnemonic E-S-R-C-D to remember the features of each store: Encoding, Storage, Retrieval, Capacity, and Duration.

Example: When you see a phone number, it enters Sensory Memory. You pay attention, so it moves to STM. You repeat it over and over (rehearsal) so you don't forget it, moving it to LTM.

The Working Memory Model (Baddeley and Hitch, 1974)

Baddeley and Hitch thought the Multi-Store Model was too simple. They argued that Short-Term Memory isn't just one "bin," but an active "workbench" with different parts:

  • Central Executive: The "Boss." it directs attention and decides which "assistant" should handle which piece of info.
  • Phonological Loop: The "Inner Ear." It deals with spoken and written material. It has two parts: the Phonological Store (holds words) and the Articulatory Process (your "inner voice" that repeats words to remember them).
  • Visuo-spatial Sketchpad: The "Inner Eye." It stores visual info (what things look like) and spatial info (where things are).
  • Episodic Buffer: Added later in 2000, this "binds" everything together into a single "episode" or story and communicates with Long-Term Memory.

Quick Review: The Multi-Store Model sees memory as a storage unit; the Working Memory Model sees it as an active processor.

Key Takeaway: Memory isn't just one single thing; it's a complex system of different stages and specialized components.


2. Different Types of Long-Term Memory (Tulving, 1972)

Endel Tulving realized that not all long-term memories are the same. He split them into two main types:

  • Episodic Memory: These are like your mental "diary." They are memories of personal experiences and events (e.g., your 10th birthday party). They include *when* and *where* things happened.
  • Semantic Memory: This is like your mental "encyclopedia" or "dictionary." It’s your knowledge of facts, meanings, and concepts (e.g., knowing that Paris is the capital of France). These don't usually have a specific time or place attached to them.

Analogy: Episodic memory is the movie of your life; Semantic memory is the trivia book you’ve memorized.


3. Reconstructive Memory (Bartlett, 1932)

Have you ever noticed that two people can remember the same event differently? Bartlett argued that memory is not like a video recording; it’s more like a jigsaw puzzle where we might lose some pieces and fill the gaps with what "makes sense."

Key Terms:

  • Schemas: These are mental "packages" of information based on our past experiences. For example, your "birthday party schema" probably includes cake, presents, and singing.
  • Reconstruction: When we recall a memory, we use our schemas to fill in the gaps. We might change details to fit our expectations (this is called rationalisation).

Example: In Bartlett's "War of the Ghosts" study, people heard a strange Native American ghost story. When they retold it, they changed "canoes" to "boats" because "boats" fit their cultural schemas better.

Key Takeaway: Our memories are not perfect copies of the past; they are reconstructions influenced by our culture and expectations.


4. Individual and Developmental Differences

Memory doesn't work the same for everyone, and it changes as we age.

Developmental Issues

  • Memory Span: Sebastián and Hernández-Gil (2012) found that our "digit span" (how many numbers we can remember) increases as we get older. It is quite low at age 5 and keeps developing until about age 17.
  • Alzheimer’s Disease: This is a condition affecting older people where the brain's ability to store and retrieve memories (especially episodic ones) is damaged.

Individual Differences

  • Processing Speed: Some people naturally process info faster than others.
  • Dyslexia: This can affect a child’s working memory, making it harder for them to hold onto and process sounds or numbers while learning.

Quick Review Box: Digits spans grow as we grow! But conditions like Alzheimer's can cause memory to fade later in life.


5. Research Methods in Cognitive Psychology

To study the mind, psychologists use Experiments. This is the most scientific way to see if one thing causes another.

The Basics:

  • Independent Variable (IV): The thing the researcher changes (e.g., whether a list of words rhymes or not).
  • Dependent Variable (DV): The thing the researcher measures (e.g., how many words the participant remembers).
  • Laboratory Experiment: Done in a controlled room. High control, but can feel "fake" (low ecological validity).
  • Field Experiment: Done in a real-life setting (like a school). More "real," but harder to control.

Hypotheses (Predictions):

  • Null Hypothesis: Predicting there will be no difference.
  • Directional (One-tailed): Predicting exactly *which* way the results will go (e.g., "Group A will remember *more* than Group B").
  • Non-directional (Two-tailed): Predicting there will be a difference, but not saying which group will be better.

Experimental Designs:

  1. Independent Groups: Different people in each group. (Avoids order effects like getting tired, but participant variables like natural intelligence can be a problem).
  2. Repeated Measures: The same people do both tasks. (Saves money, but order effects are a risk). Researchers use counterbalancing (half do task A then B, the other half do B then A) to fix this.
  3. Matched Pairs: Different people, but they are "twinned" based on things like age or IQ.

The Case Study of Henry Molaison (HM)

HM was a famous patient who had surgery to stop seizures. The surgery accidentally destroyed his ability to make new Long-Term Memories. He could remember things for about 30 seconds (STM), but he couldn't remember what he had for lunch 5 minutes ago. This provided qualitative data showing that STM and LTM are truly separate stores.


6. Classic and Contemporary Studies

Classic Study: Baddeley (1966b)

Aim: To see if LTM encodes info acoustically (by sound) or semantically (by meaning).

Method: Participants were given lists of words:

  • List A: Acoustically similar (cat, mat, sat).
  • List B: Acoustically dissimilar (pit, few, cow).
  • List C: Semantically similar (big, large, huge).
  • List D: Semantically dissimilar (hot, pen, blue).

Results: After a 20-minute delay (testing LTM), participants struggled most with List C (semantically similar). They got the meanings confused.

Conclusion: LTM encodes semantically. If words mean the same thing, they get "muddled" in our long-term storage.

Contemporary Study: Sebastián and Hernández-Gil (2012)

Aim: To investigate how "digit span" (how many numbers you can remember) develops in Spanish children aged 5–17.

Findings: Digit span increased with age. They also compared their results to people with Alzheimer's and found that the digit span of elderly Alzheimer’s patients was similar to that of a 6-year-old child.


7. Inferential Statistics

Once we have our data, we need to know if the results happened by chance or if they are "significant."

  • Probability (p): Usually, psychologists look for \(p \le .05\). This means there is only a 5% chance the results happened by luck.
  • Mann-Whitney U: Use this when you have Independent Groups.
  • Wilcoxon: Use this when you have Repeated Measures.

Common Mistake: Don't confuse the two! Mann-Whitney is for Multiple groups; Wilcoxon is for Within the same group.

Quick Review:
1. Collect data.
2. Choose the right test (Mann-Whitney or Wilcoxon).
3. Find the Observed Value from your data.
4. Compare it to the Critical Value in a table.
5. If your result is significant, you can reject the Null Hypothesis!

Key Takeaway: Statistics help us prove that our psychological theories are backed by solid evidence, not just lucky guesses.


Great job! You've made it through Cognitive Psychology. Remember, if any part feels tricky, try coming up with your own everyday analogy to help it stick!