The forgetting curve (Hermann Ebbinghaus) shows that memory loss happens fastest right after learning and then levels off over time—you lose a lot of what you just learned in the first hour to day, then the rate slows. AP-relevant reasons you forget so fast: decay (trace fading over time), encoding failure (you never encoded details into long-term memory), and interference—proactive (old info blocks new) or retroactive (new info blocks old). Retrieval failures—like tip-of-the-tongue—mean the memory’s there but you can’t access it. Memory errors also come from constructive processes: misinformation, source amnesia, or imagination inflation. For the AP exam, be ready to explain these causes and connect them to the forgetting curve (CED 2.7.A.1–2.7.A.4). Want quick review and practice? Check the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and hundreds of practice problems (https://library.fiveable.me/practice/ap-psych-new).

Short answer: because different causes of forgetting act at different times. Right after you study, the forgetting curve (Ebbinghaus) shows rapid loss unless you encode deeply or use spaced practice—decay and encoding failure are common early reasons. You might not have rehearsed or semantically encoded that new info, so it’s hard to retrieve (tip-of-the-tongue or retrieval failure). Older memories that feel random were likely encoded stronger (emotional, repeated, or well-consolidated) or later reconstructed (constructive memory), so they stick. Interference also matters: proactive interference (old info blocking new) or retroactive (new learning messing up old) can make fresh study vanish. Plus memory errors like misinformation, source amnesia, and imagination inflation change what you “remember” over time. If you want exam-ready review of these CED terms (forgetting curve, encoding failure, interference, repression, misinformation effect, source amnesia, constructive memory), use the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Proactive interference: old information interferes with your ability to learn or retrieve new information. Example: because you learned French first, you keep using French words when trying to remember newly learned Spanish vocabulary. Retroactive interference: new information makes it harder to recall older information. Example: after studying Spanish, you can’t remember some French words you used to know. Both are forms of interference (CED 2.7.A.2) that cause retrieval failure even when encoding was successful. Time and similarity matter: interference is stronger when memories are similar and when learning happens close together. These concepts show up often on the AP exam in multiple-choice and FRQ prompts about forgetting and retrieval errors (Topic 2.7). For a quick review, check the Topic 2.7 study guide on Fiveable (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Encoding failure means info never got turned into a usable memory in the first place—so it’s not “lost,” it was never stored. Think of encoding like saving a file: if you only glance at something (shallow processing), you don’t write a good file. Deep processing (thinking about meaning, making connections, using imagery or examples) makes stronger encoding. That’s why you often can’t remember a classmate’s name you saw once—you never encoded it well. Encoding failure is one reason retrieval fails alongside interference and decay (the forgetting curve shows most forgetting happens soon after learning and then levels off). Tip-of-the-tongue moments are retrieval problems, not encoding. For AP exam prep, know encoding failure vs. interference vs. retrieval failure (CED 2.7.A.2). For a focused review, check the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

The tip-of-the-tongue (TOT) phenomenon is a common retrieval failure where you feel certain you know a word or name but can’t produce it right then—you often recall partial info (first letter, number of syllables, similar-sounding words). In AP terms it’s an example of retrieval failure/blocking: the memory was encoded but can’t be accessed. Causes include interference (other similar memories compete), weak or mismatched retrieval cues, and incomplete consolidation of the memory’s associations. TOTs show that remembering isn’t all-or-nothing—partial activation of a memory’s network can give you “feeling of knowing” without full recall. On the exam, link TOT to retrieval failure and interference (CED 2.7.A.2). For a quick review of forgetting and related concepts, check the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Short answer: “Repression” (a psychodynamic idea) says we unconsciously push distressing memories out of conscious awareness to protect the ego—but it’s controversial and not well supported by modern research. Longer: AP CED lists repression as a psychodynamic theory (2.7.A.3), but most memory scientists find other explanations more convincing: traumatic events are often encoded strongly and remembered vividly, not neatly forgotten. Memory failures are better explained by encoding failure, interference, decay, or retrieval problems (2.7.A.1–2.7.A.2). Recovered-trauma claims can reflect constructive memory errors, imagination inflation, misinformation effects, or source amnesia (2.7.A.4) rather than a literal “push it away” process. So you might see “repression” on the exam as a perspective to name/define, but for empirical causes of forgetting rely on encoding/retrieval/interference and the research on false memories (Loftus) for evidence. For review, check the Topic 2.7 study guide (Fiveable) here: https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX and practice Qs at https://library.fiveable.me/practice/ap-psych-new.

The misinformation effect happens when post-event information changes how you remember an original event: misleading questions, news reports, or conversations can implant details or alter your memory during consolidation, producing a constructive memory or imagination inflation. Elizabeth Loftus’s research shows people can confidently recall things that never happened after exposure to false details. Eyewitness testimony is unreliable because of (1) misinformation effect, (2) source amnesia—you remember the content but forget where it came from—and (3) normal encoding/retrieval failures and interference; time also makes memories decay (forgetting curve). On the AP exam, expect questions that name these processes (misinformation effect, source amnesia, constructive memory) and explain why memory errors occur (CED 2.7.A, 2.7.A.4). Want more practice? Review Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and try practice problems (https://library.fiveable.me/practice/ap-psych-new).

Source amnesia is when you remember a fact, story, or skill but can’t remember where you learned it—so you might think an idea came from you when it actually came from someone else. It’s an error of source memory (a kind of retrieval/encoding problem) and often shows up with the misinformation effect or constructive memory: details get filled in, and the original source gets lost. Regular forgetting (like decay, interference, or tip-of-the-tongue) is failing to retrieve the info itself. With source amnesia the content is accessible but its origin is wrong or missing; with ordinary forgetting the content itself is what’s lost. Both fit Topic 2.7 links to encoding failure, retrieval failure, and memory distortion in the CED. For more practice and definitions, check the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and extra practice questions (https://library.fiveable.me/practice/ap-psych-new). On the exam, expect source amnesia to appear in questions about memory accuracy, misinformation effect, or constructive memory.

Memories change because memory is a reconstructive, not a perfect, static store. Time itself causes forgetting (Ebbinghaus’s forgetting curve/decay), so memory strength drops quickly after learning and then levels off (2.7.A.1). But forgetting also happens from encoding failure (you never stored details), interference—proactive (old info blocks new) and retroactive (new info blocks old)—and retrieval failure (tip-of-the-tongue) (2.7.A.2). Psychodynamic theory adds repression as a defense (2.7.A.3). Memories can also be altered during consolidation or later recall: the misinformation effect, source amnesia, and constructive memory (imagination inflation) change details over time (2.7.A.4, Loftus). For AP prep, know these specific causes and key terms—they show up on multiple-choice and FRQs for Unit 2 (Topic 2.7). Review the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Constructive memory is the idea that memories aren’t exact recordings but are rebuilt from bits of stored info, schemas, and current cues during consolidation and retrieval. Because memory is constructive, details can be filled in, changed, or combined with other knowledge (this links to misinformation effect and source amnesia in the CED). Imagination inflation happens when vividly imagining an event makes you more likely to believe it actually happened—imagining boosts the memory trace during consolidation, so later you can’t tell if the memory came from experience or imagination. Elizabeth Loftus’s work connects here: suggestive info or imagined scenarios can create confident but false memories. For AP review, focus on constructive memory, misinformation effect, source amnesia, and imagination inflation in Topic 2.7 (study guide: https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX). For extra practice, try the 1,000+ practice problems (https://library.fiveable.me/practice/ap-psych-new).

Think of Ebbinghaus’s forgetting curve: you lose a lot fast, then it levels off. Use that to plan spaced (distributed) study and active retrieval. Right after learning, do a quick recall (within 24 hours), then review at expanding intervals (3 days, 1 week, 2–4 weeks, and before the exam). Use testing yourself (flashcards, practice multiple-choice, free-response prompts) rather than rereading—testing effect beats passive review. Deepen encoding to prevent encoding failure: make meaning (elaborative rehearsal), use mnemonics, link facts to examples. Reduce interference by studying similar topics at different times and sleep after studying to help consolidation. Practice retrieval under exam conditions (timed MC sets and timed FRQs) because AP Psych tests both (75 MC, 2 FRQs). For Topic 2.7 review and CED terms (forgetting curve, interference, tip-of-the-tongue, misinformation), see the Fiveable study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and use 1000+ practice problems (https://library.fiveable.me/practice/ap-psych-new).

If you never encoded a memory, it was never stored in long-term memory to begin with—so you can’t retrieve what wasn’t recorded. Encoding failure happens when info never moves from sensory/short-term into durable memory (e.g., you glanced at a penny but didn’t attend to its details). Retrieval failure means the memory was encoded and stored but you can’t access it right now (e.g., tip-of-the-tongue, or interference like proactive/retroactive blocking). Key CED terms: encoding failure vs. retrieval failure, interference, and the tip-of-the-tongue phenomenon. The forgetting curve (Ebbinghaus) shows how time and lack of encoding reduce recall, but retrieval problems can often be fixed with cues or context reinstatement. For AP review, see the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Psychodynamic theorists say forgetting can be motivated—repression: the ego pushes distressing memories out of conscious awareness to protect you (CED 2.7.A.3). Is it “real”? Sort of—there’s evidence people sometimes unintentionally forget or avoid trauma-related details (motivated forgetting), but long-term, reliable scientific proof of Freud’s broad repression idea is mixed. Cognitive explanations (encoding failure, interference, retrieval failure) and research on misinformation, source amnesia, and constructive memory often better explain many memory errors (CED 2.7.A.1–2, 2.7.A.4). For the AP exam, you should be able to identify the psychodynamic claim about repression and also contrast it with cognitive causes of forgetting. If you want a tidy review of this topic and exam-style practice, check the Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and try practice questions (https://library.fiveable.me/practice/ap-psych-new).

False memories feel real because memory is reconstructive, not a perfect recording. During consolidation and retrieval your brain fills gaps using schemas, imagination, and related knowledge. Processes like the misinformation effect (Loftus’ work), source amnesia (forgetting where a memory came from), and imagination inflation can make imagined or suggested events blend with real ones, so details feel vivid and confident even if they’re wrong. Interference and encoding failures also weaken true traces, making the brain rely more on reconstruction—which feels just as real. On the AP exam this links to EK 2.7.A.4 (misinformation effect, source amnesia, constructive memory) and is a common multiple-choice/frq topic, so know those terms and examples. If you want a quick refresh, check the Topic 2.7 study guide on Fiveable (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).

Memory consolidation is the process that stabilizes a memory after encoding—moving it from fragile short-term/working storage into longer-term forms. During consolidation, details can be strengthened or changed: accurate sensory/context cues get integrated, but gaps are filled in using existing knowledge (constructive memory). That’s why consolidation can produce both stable recall and errors. Problems like misinformation effect, source amnesia, or imagination inflation often happen after consolidation when new or similar info interferes (retroactive/proactive interference) or when you can’t remember the original source. Over time the forgetting curve shows rapid loss then leveling off, so poorly consolidated memories are more likely to be lost or distorted (tip-of-the-tongue fits retrieval failure). For AP exam prep, know these CED terms (memory consolidation, constructive memory, misinformation effect, source amnesia) and expect multiple-choice or FRQ items asking you to explain how consolidation causes accurate recall versus errors. Review Topic 2.7 study guide (https://library.fiveable.me/ap-psych-new/unit-3/7-forgetting-and-other-memory-challenges/study-guide/Nc5yYMuimH6LqneX) and practice questions (https://library.fiveable.me/practice/ap-psych-new).