Unit 2 · 2.5
Storing Memories
Unit 2 is 15–25% of the multiple-choice section. Storage items are lost when every memory is treated as a video in a hippocampal hard drive — or as one file that can be ‘photographic.’ · about 5 minutes with the essay beats.
You do not remember what happened. You remember what you encoded — and what later got in the way.
Read the scene first. The term will wait. When it lands, you will be able to use it on a stranger’s story — that is the exam, and that is also why this subject is interesting.
A scene you already lived
Do not hunt the term yet. Let this sit. The exam will hand you a stranger’s version of the same night.
Cardamom on the stove and you are eight again — a kitchen you do not live in now, a sentence you did not try to save. Then a password you type every morning and cannot recite to a friend. Storage is not one drawer. A smell can yank an episode. A procedure can live in the fingers. A fact can sit without a personal movie attached. The hippocampus is involved in consolidating many explicit traces. It is not the hard drive of your personality, and it is not proof that memories are video files in a single folder. Photographic memory as a home movie is a story this course will not mark as science.
What the paper actually asks
These are the scoring targets. If you can do them on a new story, you are ready — flashcards can wait.
- Distinguish sensory, short-term/working, and long-term storage at AP grain.
- Separate explicit from implicit; episodic from semantic.
- Connect hippocampus and related systems without neuromyth.
The mechanism
Once you can walk this, you will start seeing it at dinner, in a group chat, in your own delay. That is the fun of this course.
Duration and system first. Sensory storage: a blink-long trace of just-seen or just-heard input. Short-term / working storage: a limited workspace you can rehearse or manipulate. Long-term storage: more durable traces — not infinite video, not one drawer. 2.3 gave you the map; this page sorts what long-term can hold.
Explicit (declarative) memory is for what you can say. Episodic: a personal episode, a time and a place (‘the cardamom kitchen’). Semantic: facts and meanings without that personal movie (‘cardamom is a spice’; ‘the capital is…’). Implicit memory is for what shows up in behavior without that ‘I remember that’ report. Procedural: how to ride, type, tie. Priming: a recent cue makes a related response easier. Classical-conditioning traces can live here too — a learned bodily reaction that is not a story you tell. These are AP-grain families, not proof of separate USB sticks in the skull.
The hippocampus matters for forming many new explicit traces and for consolidation — the stabilizing of a trace over time, including a role for sleep you already met in 1.5. It is not a filing cabinet of personality, not where ‘you’ live, and not a hard drive that stores every skill. Procedural learning involves other systems (classroom-common: cerebellum and related motor circuits). Emotion can tag some episodes (amygdala as a neighboring name) without turning them into perfect recordings. Memories do not live in one file drawer. The 10%-of-the-brain story is false here too.
Sensory
brief, raw
Working
workspace now
Long-term
durable, not a video file
Episodic
episodes you can place
Semantic
facts without the scene
Implicit
skills, priming, conditioning
Words worth owning
A definition is a tool. The confusable is the distractor. Learn both and the clever wrong answer stops working.
Sensory storage
A very brief hold of just-seen or just-heard input before it is selected or lost.
Confusable. Not a childhood smell returning years later — that returning episode is long-term, often explicit.
Short-term / working storage
A limited, temporary workspace for holding and manipulating information you are using now.
Confusable. Not long-term procedural skill. A password you can type but not recite may be procedural plus a working-memory trick.
Explicit memory
Memory you can declare — episodes and facts you can report as ‘I remember’ or ‘I know.’
Confusable. Implicit is skill, priming, or conditioned response without that report. Explicit is not ‘true’ and implicit ‘false.’
Episodic memory
Explicit memory for a personal event in time and place.
Confusable. Semantic is fact without that personal movie. Both can be explicit.
Semantic memory
Explicit memory for facts, meanings, and general knowledge, not tied to one personal event.
Confusable. Not implicit. Knowing that Paris is a capital is semantic even if you have never been.
Implicit memory
Memory expressed in behavior without a required conscious report — procedural skill, priming, some conditioning.
Confusable. Not ‘repression’ (a contested 2.7 idea). Not a hidden video.
Procedural memory
Implicit memory for how to do something — riding, typing, a sport motion.
Confusable. The story of yesterday’s ride is episodic. The how-to is procedural.
Consolidation
The process of stabilizing a memory trace over time; the hippocampus is involved in many new explicit traces.
Confusable. Not ‘the hippocampus is the hard drive of personality.’ Not a 10%-of-brain claim. Not photographic storage.
A study you can actually use
Classic or labeled hypothetical. Either way: what was done, what was found, what it cannot claim.
Classic (classroom-common) · mid-20th century (classroom-common clinical case)
H.M. as a classroom-common consolidation case
- What was done
- After surgical removal of large parts of the medial temporal lobes including the hippocampus, H.M. could hold a short conversation (working memory) and retain many skills and much knowledge from before the surgery, but often could not form lasting new explicit episodes.
- Finding
- Systems can split: a limited present-moment hold can survive while new long-term explicit storage is devastated. Skill learning can be less dependent on the same hippocampal path. That is a systems point, not a soap opera.
- Limit — what it cannot claim
- One patient, one surgery, a historical case. Not a map of your personality. Not proof that ‘memories live in the hippocampus’ as a drawer. Classroom accounts simplify. Do not invent test scores.
- How AAQ would probe it
- Method: case study. Limit: n = 1, unique lesion. Application: hippocampus and consolidation of new explicit memory; working memory and some implicit skill can dissociate. Ethics: a clinical case is a person, not a toy.
Labeled hypothetical
Hypothetical smell-cued episode vs typed password (original practice source, not a published paper)
Original practice source, not a published paper.
- What was done
- Researchers ask 24 volunteers to (a) report any personal scene a spice odor brings to mind, and (b) type a well-practiced lock code, then try to recite the same code aloud in order.
- Finding
- A fair teaching claim: an odor may retrieve an episodic report while a procedure (typing) can be intact when recitation is poor — different long-term families, not one video file with a missing minute.
- Limit — what it cannot claim
- Labeled hypothetical. Self-report of a scene is not a brain scan. Reciting vs typing is an operational split, not a diagnosis. Do not cite this as a real paper or invent a percent of ‘perfect odor memories.’
- How AAQ would probe it
- Method: structured observation / within-person tasks, not an experiment unless an odor was randomly assigned vs a control scent. Application: episodic vs procedural. Limit: no license for photographic-memory claims.
Someone’s Tuesday
If it only lives in the textbook, it will not survive a novel stem. This is the idea wearing ordinary clothes.
You still ride a bicycle after a year off (procedural) and cannot tell the story of last Tuesday’s ride (episodic). You know what a referee is (semantic) without remembering the lesson. A brand logo makes a related word come faster (priming). A password lives in the fingers and dies on a blank line. A smell in a stairwell yanks a kitchen you did not encode on purpose. None of that requires a 10% brain myth, a personality hard drive, or a claim that you remember ‘everything’ as video.
Where clever students go wrong
The trap is usually a neighboring term that almost fits. Name it so it stops feeling smart.
Photographic memory as a home movie: not how this course treats ordinary storage. ‘The hippocampus is the hard drive of personality’ is neuromyth dressed as anatomy. Memories do not live in one file drawer. ‘We use 10% of the brain’ stays false. Implicit is not repression and not a secret second self. A preserved skill after a gap is not proof that explicit episodes are also preserved.
A stem, then the move
Watch me work one. Then you will do four without looking back.
Scenario
Yara can still play a well-learned piano piece after the holidays, cannot recount Tuesday’s practice in order, and can define ‘tempo’ without remembering which teacher first said it. A cinnamon roll in the canteen yanks a grandmother’s kitchen. Sort the stores.
Walkthrough
The piece is procedural (implicit). Tuesday’s practice as a personal event is episodic (explicit) — and it is missing. ‘Tempo’ as a meaning is semantic (explicit). The kitchen is an episodic retrieval by a smell cue, not sensory memory (sensory is a blink, not a childhood). Hippocampal consolidation talk is not required unless the stem asks where new episodes are formed. Do not call the piano ‘photographic.’
The move
Procedural; failed episodic for Tuesday; semantic for the term; episodic for the kitchen. Different long-term families, not one drawer.
Try tonight · 5 minutes
A living experiment, not a vibe
Do this on your actual Tuesday. The paper will later hand you a stranger’s version of the same five minutes.
Name one thing you can do (procedure), one fact you know without a scene, and one scene a smell or song yanks. Write which long-term family each is. Do not diagnose anyone.
Prove it
Four items. No looking back.
One at a time. After each submit I will show the key, why it is right, and why the others felt clever.
Item 1 of 4 · Practice 1 · Concept application
A cinnamon roll in the canteen yanks Yara into a grandmother’s kitchen she did not try to memorize. She can still type a lock code she cannot recite. Which split is most accurate?
Keys A–D select. Enter checks.
Write it · AAQ
A case study’s claim about storage
Say the move in your own mouth. If you can write it, you own it — rereading is not the same thing.
Classroom-common clinical case (H.M.-style): after hippocampal surgery, a patient holds a short conversation, learns a motor trick over days without reporting the sessions, and does not keep new personal events. Identify the research method. Then name one storage system that appears relatively spared and one that appears devastated, without treating the hippocampus as a personality hard drive.
Move: Method: case study. Spared: working memory and/or procedural. Devastated: new episodic/explicit. Limit: n = 1, not a drawer of the self.
Where curiosity goes next
Related rooms. Open the one that still tugs.