Cognitive Psychology — The Structure of Memory, Encoding and Retrieval, Forgetting and Distortion, Attention, Thinking and Problem Solving

The cognitive revolution: the mind as information processing

Until the mid-20th century, mainstream psychology was behaviourism, which studied only observable behaviour. With the arrival of computers in the 1950s and 60s, the view of the mind as a system that takes in, stores and retrieves information gained ground. Neisser’s (1967) Cognitive Psychology brought this movement together as a field.

Miller (1956) proposed that people can hold about seven plus or minus two items at once, but later research suggests that when rehearsal and grouping are prevented, true capacity is closer to about four (Cowan, 2001). Chunking — grouping information into meaningful units, as when you memorise a phone number in three parts — is the key strategy for getting past this limit.

The structure of memory

The multi-store model

Atkinson and Shiffrin (1968) described memory as three stores.

1. Sensory memory: holds what the eyes and ears take in for a very short time (under a second for vision).
2. Short-term memory: only attended information passes in, and it fades within tens of seconds without rehearsal.
3. Long-term memory: stores information for a long time with almost unlimited capacity.

Working memory

Baddeley and Hitch (1974) argued that short-term memory is not a simple storeroom but a workbench for holding and manipulating information, and proposed the working memory model.

• Phonological loop: maintains speech-based information through inner rehearsal.
• Visuospatial sketchpad: handles images and locations.
• Central executive: allocates attention and coordinates the whole.
• Episodic buffer: binds different information and long-term memory into a single scene (Baddeley, 2000).

This structure explains why listening to an explanation while rehearsing other words disrupts both, whereas listening while looking at a picture works relatively well.

Kinds of long-term memory

Category	Type	Example
Declarative (explicit)	Episodic memory	What happened on your last birthday
	Semantic memory	The fact that Seoul is the capital of Korea
Non-declarative (implicit)	Procedural memory	Riding a bike, typing
	Priming, conditioning	Recognising a word faster after seeing it once

Tulving (1972) distinguished episodic from semantic memory. The patient H.M., who had tissue around both hippocampi removed in epilepsy surgery, could no longer form new episodic memories, yet his motor skills, such as mirror drawing, improved with practice (Scoville & Milner, 1957) — powerful evidence that memory is not a single system.

What makes things stick: encoding and retrieval

• Levels of processing: Craik and Lockhart (1972) proposed that processing meaning deeply leads to better memory than processing appearance or sound.
• Encoding specificity: retrieval is easier when the context at learning is present again at recall. In Godden and Baddeley’s (1975) experiment, words learned underwater were recalled better underwater, and words learned on land better on land.
• Retrieval practice (the testing effect): practising recall is far more effective for long-term memory than rereading. In Roediger and Karpicke’s (2006) experiment, the retrieval-practice group scored higher on a test a week later.
• The spacing effect: reviewing spread out over time leads to longer-lasting memory than cramming. A meta-analysis of hundreds of experiments confirmed this (Cepeda et al., 2006).

Forgetting and distortion

The forgetting curve and interference

Ebbinghaus (1885) memorised nonsense syllables and measured how much he retained over time, drawing a forgetting curve in which forgetting is rapid at first and then slows. Forgetting stems not only from decay over time but also from proactive interference, where earlier learning disrupts new memories, and retroactive interference, where new learning disrupts older ones.

Memory is reconstructed

• The misinformation effect: Loftus and Palmer (1974) showed people a film of a car crash; asking how fast the cars were going when they “smashed” into each other led to higher speed estimates than “hit,” and a week later more people reported seeing broken glass that wasn’t there.
• False memory (DRM): Roediger and McDermott (1995) read lists such as “bed, rest, dream, pillow…” and found that many people were confident they had heard “sleep,” which was not on the list.

Memory is less a video recording than a story rebuilt each time we recall it. That is why this research matters so much in handling eyewitness testimony.

Attention: allocating a limited resource

In Cherry’s (1953) cocktail party effect studies, when different messages were played to each ear, people who attended to one side remembered almost nothing from the other — yet they noticed their own name.

• Filter model: Broadbent (1958) saw attention as an early bottleneck that filters information.
• Attenuation model: Treisman (1964) revised this: filtered information isn’t lost but weakened, so important information like your name breaks through.
• Perceptual load theory: Lavie (1995) explained that the more perceptually demanding the current task, the less distracting stimuli are processed.

Inattentional blindness, failing to see what is in plain view, is covered further in the article on the limits of attention and memory.

Thinking and problem solving

Kahneman (2011) popularised the dual-process view of a fast, intuitive System 1 and a slow, deliberate System 2. Intuition is usually useful but can produce systematic errors in probability judgements (heuristics and biases). The representativeness, availability and anchoring heuristics are covered in detail in the article on judgement shortcuts.

A classic obstacle to problem solving is functional fixedness. In Duncker’s (1945) candle problem, people saw the box holding the tacks only as a “container” and struggled to think of using it as a candle holder. Restating the problem, stepping away for a while (incubation) and borrowing solutions from structurally similar problems (analogy) help break such fixedness.

Check questions

Question 1. A week before an exam, a student wonders whether to reread the textbook three times or read it once and spend the rest of the time making and answering their own questions. Which does research favour?

Answer. Retrieval practice — recalling on your own — is more effective (the testing effect). Adding the spacing effect by spreading review over several days helps long-term memory even more.

Question 2. An accident witness is asked, “How fast was the red car going when it ran the light?” What is the problem with this question?

Answer. The question itself can plant the information “red car” and “ran the light.” This is the misinformation effect, which can alter the witness’s memory. Neutral, open questions should be used.

Question 3. Explain with the working memory model why talking on the phone while driving is dangerous.

Answer. Understanding the conversation and preparing replies draws on the central executive, leaving fewer resources for monitoring the road and making judgements. Hands-free devices don’t solve this problem.

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References

• Neisser, U. (1967). Cognitive Psychology. Appleton-Century-Crofts.
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• Cowan, N. (2001). The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24(1), 87–114.
• Atkinson, R. C., & Shiffrin, R. M. (1968). Human memory: A proposed system and its control processes. In K. W. Spence & J. T. Spence (Eds.), The Psychology of Learning and Motivation (Vol. 2, pp. 89–195). Academic Press.
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