What are the major models and systems of human memory?
Topic 2.3 Introduction to Memory: describe the major models of memory, including the three-stage information-processing model and the different memory systems.
A focused answer to AP Psychology Topic 2.3, introducing the three-stage information-processing model (sensory, short-term, long-term memory), working memory, the multi-store and levels-of-processing models, and the distinction between explicit and implicit memory.
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What this topic is asking
Topic 2.3 introduces memory by laying out its major models and systems. The College Board wants you to explain the three-stage information-processing model (sensory, short-term, long-term memory), the idea of working memory, alternative models like levels of processing, and the distinction between explicit and implicit memory. This frames Topics 2.4 to 2.7, which detail encoding, storage, retrieval, and forgetting.
The three-stage model
Information moves through these stages: it enters sensory memory, and if attended to, passes to short-term memory, and if rehearsed or encoded, passes to long-term memory. Without attention or rehearsal, it is lost.
The three stores in detail
The famous "magical number seven" describes short-term memory's narrow capacity. Chunking (grouping items into meaningful units) and rehearsal (repeating information) extend what short-term memory can hold and help move it to long-term storage.
Working memory
The newer concept of working memory refines short-term memory. Rather than a passive store, working memory is an active system that manipulates information, for example holding a phone number while dialing or doing mental arithmetic. It includes components for visual and verbal information and a central controller that directs attention.
Alternative models
The levels-of-processing model offers a different emphasis: memory strength depends on how deeply information is processed. Shallow processing (by appearance or sound) yields weak memories, while deep processing (by meaning, called semantic encoding) yields strong, durable ones. This explains why understanding material beats rote repetition.
Explicit and implicit memory
Long-term memory divides into two broad types:
- Explicit (declarative) memory: consciously recalled facts and experiences. It includes semantic memory (general knowledge) and episodic memory (personal events).
- Implicit (nondeclarative) memory: unconscious, automatic memory. It includes procedural memory (skills like riding a bike) and conditioned associations.
The reason these distinctions matter is that memory is not one thing but a set of cooperating systems with different rules, capacities, and brain bases. The same studying episode draws on all of them at once: sensory memory registers the page, working memory juggles the current idea, deep semantic processing carries it into long-term explicit memory, and the well-practiced act of writing notes runs on implicit procedural memory. Recognizing which system a scenario is testing is the core exam skill of this part of Unit 2, because the later topics, encoding, storage, retrieval, and forgetting, each describe a different point in this flow. A clear mental map of the stages and types lets you place any memory phenomenon and predict where it can break down.
Try this
Q1. State the capacity and duration of short-term memory. [2 points]
- Cue. About 7 (plus or minus 2) items, held for roughly 20 seconds without rehearsal.
Q2. Distinguish explicit from implicit memory with an example of each. [2 points]
- Cue. Explicit (declarative) memory is consciously recalled, such as a historical date; implicit (procedural) memory is unconscious and automatic, such as riding a bike.
Exam-style practice questions
Practice questions written in the style of College Board exam questions on this dot point, with worked answer explainers. The year tag is the paper they imitate, not the source.
AP 2023 (style)1 marksMultiple choice. According to the three-stage information-processing model, information must first enter which memory store before it can be processed further? (A) Long-term memory (B) Short-term memory (C) Sensory memory (D) Implicit memory (E) Procedural memoryShow worked answer →
The answer is (C) Sensory memory.
In the three-stage (Atkinson-Shiffrin) model, incoming information first enters sensory memory, a brief, large-capacity store that holds raw sensory input for a fraction of a second. Attended information then moves to short-term (working) memory, and with rehearsal or encoding it passes to long-term memory.
(A) long-term and (B) short-term memory are later stages. (D) implicit and (E) procedural memory are types of long-term memory, not the first stage. Only sensory memory is the entry point.
AP 2022 (style)5 marksConcept-application free-response question. A student is studying for an exam. Explain how EACH of the following is involved in the student's memory: sensory memory, short-term (working) memory, long-term memory, explicit memory, and implicit memory.Show worked answer →
A 5-point concept-application FRQ; one point per term.
Sensory memory (1): briefly holds the raw visual input of the textbook page before the student attends to it.
Short-term (working) memory (1): holds and actively manipulates the small amount of information the student is currently studying.
Long-term memory (1): the relatively permanent store where studied material is kept for the exam.
Explicit memory (1): the consciously recalled facts and concepts (declarative knowledge) the student is learning.
Implicit memory (1): the unconscious, automatic memory, such as the learned skill of writing or a conditioned study habit.
Markers reward each term being correctly defined AND tied to the studying scenario.
Related dot points
- Topic 2.4 Encoding Memories: explain the processes of encoding information into memory, including effortful and automatic processing, levels of processing, and mnemonic strategies.
A focused answer to AP Psychology Topic 2.4, covering automatic and effortful processing, the levels-of-processing effect, semantic encoding, mnemonic devices, chunking, the spacing effect, and the self-reference and testing effects that strengthen encoding.
- Topic 2.5 Storing Memories: describe how memories are stored, the types of long-term memory, and the brain structures and processes involved in memory storage.
A focused answer to AP Psychology Topic 2.5, covering the types of long-term memory (explicit, implicit, semantic, episodic, procedural), the roles of the hippocampus, cerebellum, and amygdala, long-term potentiation, and how flashbulb memories are stored.
- Topic 2.6 Retrieving Memories: explain the processes of retrieval, the difference between recall and recognition, and the cues and effects that aid or distort retrieval.
A focused answer to AP Psychology Topic 2.6, covering recall versus recognition, retrieval cues and priming, context-dependent and state-dependent memory, mood congruence, the serial position effect, and the reconstructive nature of retrieval.
- Topic 2.7 Forgetting and Other Memory Challenges: explain the causes of forgetting, including encoding failure, decay, interference, and retrieval failure, and how memory can be distorted.
A focused answer to AP Psychology Topic 2.7, covering encoding failure, storage decay (Ebbinghaus forgetting curve), proactive and retroactive interference, retrieval failure, amnesia, the misinformation effect, source amnesia, and constructed false memories.
- Topic 2.1 Perception: explain bottom-up and top-down processing, perceptual organization and constancies, depth and gestalt principles, and the influence of attention and set.
A focused answer to AP Psychology Topic 2.1, covering bottom-up and top-down processing, gestalt grouping principles, depth cues, perceptual constancies, selective attention, perceptual set, and how prior knowledge shapes what we perceive.
Sources & how we know this
- AP Psychology Course and Exam Description — College Board (2024)