lecture 19 - incidental forgetting Flashcards

Question

passage of time as a cause of forgetting

Answer 1

Passage of Time & Forgetting 📉 Trace Decay Theory Suggests memories fade over time, like a sign exposed to weather. Often invoked in explaining forgetting in working memory and familiarity effects. Distinction: Activation decay: Concept remains but activation fades. Structural decay: Associations or features of a memory degrade over time. 🔬 Biological Evidence for Decay Memory traces rely on neural tissue, which is biologically unstable: Neurons die, connections weaken or change. In Aplysia, learned behaviors fade with synaptic weakening (Bailey & Chen, 1989). Active forgetting found in: Fruit flies (dopaminergic neurons erase odor fear). Rodents (hippocampal synapses weaken object location memory). 🌱 Neurogenesis-Induced Forgetting Frankland et al. (2013): New neurons in the hippocampus disrupt old memory traces. As new neurons integrate, synaptic connections remodel, impairing retention of prior memories. May explain infantile amnesia—poor recall of early life due to high neurogenesis in childhood. 🧪 Optogenetics in mice shows such memories are not lost, but inaccessible unless reactivated by artificial means (Guskjolen et al., 2018). ❓ Challenges in Proving Decay Behavioral proof of decay is difficult due to confounding factors like: Rehearsal (retrieval strengthens memory). Interference (new experiences disrupt old ones). To isolate decay, one must eliminate rehearsal and interference—nearly impossible in practice. Even if decay occurs, it's unclear if the memory is unavailable or just inaccessible. ✅ Key Takeaways Trace decay (both activation and structural) likely exists, but is hard to measure behaviorally. Neurobiology (e.g., neurogenesis, synaptic change) supports forgetting over time. Memories may survive structurally but become inaccessible, not erased. Modern techniques (like optogenetics) reveal lost memories can still exist in the brain.

Answer 2

For the foregoing reasons, experimental psychologists have favored the view time is merely correlated with some other factor that causes forgetting. Two possibilities have been examined. First, as time goes by, the incidental context within which we operate gradually shifts, perhaps impairing retrieval of older memories. Second, over time, people store many new similar experiences that may interfere with retrieving a particular trace. Although these factors do not disprove decay, they provide alternative explanations for the forgetting curve that do not rely upon this process.

Answer 3

Contextual Fluctuation & Forgetting 🔄 Key Concept: Context Matters for Retrieval Memory retrieval depends on the match between encoding and retrieval context. Cues used during recall are most effective when they are similar to those present during encoding. As time passes, both external (environmental) and internal (mental) contexts naturally change, making retrieval less successful. 🧭 Explanation of the Forgetting Curve Over time, contextual changes accumulate due to: Changes in appearance, emotions, environments, and experiences. This results in poorer cue-match and greater forgetting, supporting an explanation of the forgetting curve (Polyn, Norman, & Kahana, 2009). 💭 Mental Context Shifts & Daydreaming (Delaney et al., 2010) Study design: Participants studied two word lists, with a 90-second break between them. Group 1: Daydreamed about a US vacation. Group 2: Daydreamed about an international vacation. Control: Read a textbook passage. Result: Those who daydreamed recalled fewer words from the first list, especially those imagining international trips. The greater the mental distance, the more forgetting occurred. A correlation was found between vacation remoteness (in miles) and memory loss. 🧠 Why It Matters Mental context acts like physical context in retrieval. Disruptions in mental continuity (like vivid daydreams) can impair access to recently encoded information. Suggests that internal distractions—not just external ones—can lead to forgetting. ✅ Key Takeaways Contextual fluctuation (mental or environmental) reduces cue overlap and leads to increased forgetting over time. Memory depends not only on what is stored but also on whether the retrieval context aligns with the encoding context. Even brief mental shifts, such as daydreaming, can disrupt memory retrieval.

Answer 4

Interference as a Cause of Forgetting ⚠️ Core Concept: Interference happens when similar memories compete, making retrieval harder. Not all forgetting is due to time—similar experiences crowd memory, especially routines (e.g., parking or meals). 🔁 Why Interference Occurs: When a cue (e.g., "where I parked") is linked to many similar memories, these compete for retrieval. Known as the competition assumption: memory traces activated by the same cue interfere with one another. 🔑 Key Principles: Cue-Overload Principle: As more items are linked to a cue, retrieval for any single item becomes less efficient (Watkins, 1978). Competition is worse when memories share features (e.g., same car, same location, similar goals). 🧭 Real-Life Example: Remembering where you parked your car becomes harder over time as more parking episodes with similar features accumulate. Cues like "Me," "Honda," "Shopping" activate multiple parking memories, all of which compete. 🧠 Broader Application: Interference affects more than episodic memory. Even retrieving word meanings shows interference. E.g., for the word DUCK, the noun meaning ("the bird") dominates and interferes with retrieving the verb meaning ("to crouch"). 📚 Research Roots: Long history in memory research (e.g., Müller & Pilzecker, 1900; Anderson & Neely, 1996). Explains the forgetting curve: as similar experiences increase, so does retrieval competition. ✅ Key Takeaways: Interference is caused by similar memories competing for the same retrieval cues. It's worse when routines are similar, and stronger for cues linked to many items. Explains forgetting even without time-based decay—retrieval success depends not just on storage, but on cue distinctiveness.

Answer 5

A number of qualitatively distinct situations produce interference. For instance, the storage of new experiences can interfere with retrieving older ones, but older memories can also impede retrieval of newer ones. In this section, we review some of the most important interference phenomena and key results that have been discovered. It is important to bear in mind that although the particulars of these situations vary, the underlying mechanisms that produce forgetting may in fact be similar.

Answer 6

Retroactive Interference (RI) 💡 Definition: Retroactive interference occurs when new experiences impair memory for earlier ones. Forgetting happens because of newer memories, not just the passage of time. 📉 How It Works: When you learn List 1 (e.g., DOG-SKY), and then List 2 (e.g., DOG-ROCK), your ability to recall List 1 is impaired, especially when: Same cues are used across both lists. More training is given on List 2. 🧪 Classic Findings: Barnes & Underwood (1959) showed: More practice with new associations (List 2) = worse memory for old ones (List 1). Control groups (no new learning) showed less forgetting, proving that interference, not time, causes forgetting. 🏉 Real-World Example: Baddeley & Hitch (1977) tested rugby players on teams they played earlier in the season. Forgetting depended more on how many games played since, not on elapsed time. This confirmed RI in real-life episodic memory, not just lab studies. 🧠 Key Insight: RI shows that new learning competes with old learning when shared cues are involved. Interference is most damaging when new and old memories are similar. ✅ Revision Takeaways: Retroactive interference explains forgetting by competition from newer memories. Strongest when memories share retrieval cues. Supported by lab experiments and naturalistic studies (e.g., rugby players). It’s not just time, but new, similar learning that disrupts old memory.

Answer 7

Proactive Interference (PI) 💡 Definition: Proactive interference occurs when older memories interfere with the retrieval of newer ones. Classic examples: Old passwords make it hard to remember new ones. Calling your current partner by your ex’s name. Forgetting where you parked today because you remember yesterday’s spot. 🧪 Key Research – Underwood (1957): Noticed that participants showed major forgetting of nonsense syllables after 24 hours. Hypothesized this was due to prior learning in earlier experiments (common among psychology students). Found a clear pattern: Naive participants (no prior learning): remembered 80% of items. Participants with 20+ prior lists: remembered <20%. Conclusion: PI greatly increases forgetting over time. 🔬 Experimental Design: Similar to retroactive interference studies, but: Focuses on memory for List Two, not List One. Control group doesn’t learn a prior list (List One is replaced with a break or unrelated task). Finding: Prior learning impairs new learning, especially when: Lists share common cues. Recall (not recognition) is used as the memory test. ⚠️ When PI is Strongest: When: Old and new information share cues (e.g., same word or topic). Memory is tested via recall rather than recognition. ✅ Revision Takeaways: PI = Old memory disrupts new memory. Strongest when there's cue overlap and recall-based testing. Supported by real-world examples (e.g., parking, passwords) and lab research. Shows that forgetting isn't just about time—past learning can block new learning.

Answer 8

Part-Set Cuing Impairment (PSCI) 💡 Definition: PSCI occurs when recall is impaired by giving some cues from the same memory set. Example: A friend guesses names when you forget someone’s name — their suggestions may actually worsen recall. 🧪 Key Study – Slamecka (1968): Participants studied lists from categories (e.g., TREES, BIRDS). Some were cued with a few category members at test; others received no cues. Surprising result: Cued participants recalled fewer remaining items → Cues harmed recall of non-cued items. 🤔 Why Does PSCI Occur? Cues strengthen associations with the shared cue (e.g., category), increasing competition among items. As more cues are given → More competition → Worse recall. Supported by the cue-overload principle. 🔬 Bauml & Aslan (2004) – What Causes PSCI? Tested whether re-exposure or retrieval of cue items caused PSCI. 3 Groups: Part-Set Cuing → Told to use cues for recall → Impaired noncue recall. Part-Set Re-study → Re-studied cue items without retrieval → No impairment. Part-Set Retrieval → Retrieved cue items before test → Impaired noncue recall. ✅ Conclusion: Retrieving cue items, not just seeing them, causes PSCI. 👥 Related Phenomenon – Collaborative Inhibition: Groups recalling together remember less than the total recalled individually and combined. May be due to PSCI-like interference during group recall (Weldon & Bellinger, 1997). Listening to others’ responses can disrupt your own retrieval by increasing cue competition. ✅ Revision Takeaways: PSCI = Giving partial cues impairs memory for uncued items. Caused by cue-based interference, especially when cue items are retrieved. Affects both individual and group recall (via collaborative inhibition). Retrieval—not re-exposure—triggers interference.

Answer 9

Retrieval-Induced Forgetting (RIF) 🔍 Definition: RIF is the impairment of recall for related but unpracticed items due to the act of selectively retrieving other items from memory. Coined by Anderson et al. (1994). 🧪 Key Paradigm – Retrieval Practice Paradigm: Study categories (e.g., FRUITS: orange, banana; DRINKS: scotch). Practice retrieving some items (e.g., FRUIT-OR_ → ORANGE). Final test: recall all studied items. 📉 Result: Practiced items are remembered better, but unpracticed related items (e.g., banana) are recalled worse than baseline items from unpracticed categories. 📚 Real-World Implications: Selective studying (e.g., only revising some facts) may impair memory for non-reviewed, related info. Macrae & MacLeod (1999): Practicing 5/10 facts about an island improved recall for those 5 but impaired recall of the other 5 (23% vs. 38% baseline). Questioning witnesses (e.g., about only some aspects of a crime) can impair memory for unquestioned details. Studies by Shaw et al. (1995) and Migueles & García-Bajos (2007) show long-lasting forgetting (≥1 week). Selective questioning increases susceptibility to misinformation. 👦 Childhood Memory Studies: Conroy & Salmon (2006): Children remembered fewer nondiscussed elements from an event after selective questioning. Marche et al. (2016): Recalling positive parts of painful experiences can reduce memory for unpleasant aspects. 🤝 Social Contagion of Forgetting: Socially shared RIF: Cuc, Koppel & Hirst (2007): Silent observers of retrieval practice also forgot unmentioned material. Free conversations about shared events lead to mnemonic convergence—people align memories by reinforcing discussed and forgetting omitted info. Implication: Societal memory can be manipulated by what is emphasized or left unsaid. 📱 Technology & RIF: Cinel et al. (2018): Students photographed objects around campus and later reviewed only some. Reviewed objects = high recall. Unreviewed items from same locations = impaired recall → RIF via selective photo-reviewing. 📸 Mobile phones may alter autobiographical memory by fostering selective retrieval. ✅ Summary Takeaways: Retrieval strengthens practiced info but can harm related unpracticed info. Effects occur with: Studying, Witness questioning, Reminiscing, Social conversation, Digital photo review. RIF is a double-edged sword: retrieval improves memory but may cause forgetting elsewhere.

Answer 10

As the preceding discussion illustrates, many "interference" situations impair retention. Although these phenomena describe when forgetting will arise, they do not say how forgetting occurs. Why does presenting cues impair recall? Why does retrieval-induced forgetting occur? Why does introducing new learning impair retention of previously acquired material? First we consider classical mechanisms proposed to explain interference, and show how they can be extended to explain phenomena like part-set cuing and retrieval-induced forgetting. Then we consider a more recent view in which inhibitory processes associated with cognitive control underlie retrieval cause forgetting.

Answer 11

🔗 Associative Blocking 🧠 Definition: Associative blocking is the idea that stronger competing memories block access to weaker, correct ones when they share the same cue. Proposed by McGeoch (1942) as response competition theory. Updated as strength-dependent competition by Anderson et al. (1994). 📌 Key Concept: When a cue (e.g., FRUIT) is linked to multiple memories, stronger items (e.g., ORANGE) dominate retrieval. Weaker targets (e.g., BANANA) become inaccessible due to the repeated accidental retrieval of the competitor. This leads to retrieval failure, not because the memory is lost, but because it is blocked by stronger associations. 🧩 Example – Everyday Blocking: Trying to recall the British term "Christmas baubles" but “Christmas balls” (a Belgian term) keeps intruding. Eventually, the correct term pops into mind after a delay, when interference subsides. 🧪 Empirical Evidence – Smith & Tindell (1997): Participants rated words (e.g., ANALOGY), then later solved word fragments. Puzzles with orthographically similar lures (e.g., A_L__GY) were solved worse (33%) than unrelated ones (50%). Blocking was linked to reminders of earlier words, which intruded and hindered solving (Leynes et al., 2011). 📚 Blocking and Interference: Blocking helps explain several memory interference effects: Phenomenon Explanation via Blocking Retroactive interference New associations dominate cues, blocking older ones. Part-set cuing Provided cues strengthen and block retrieval of others. Retrieval-induced forgetting Practiced items (e.g., ORANGE) block non-practiced (e.g., BANANA). ⚠️ Cue-Overload Principle: More items linked to a cue = greater chance of wrong retrieval = increased blocking. E.g., Can’t recall dinner 4 months ago because recent dinners dominate recall cues. ✅ Summary Takeaways: Associative blocking is a powerful explanation for why we forget. It is not about loss of memory, but competition and cue dominance. Stronger, more recent or more practiced memories can suppress access to weaker ones

Answer 12

Associative Unlearning – Summary for Revision Associative unlearning is a theory explaining forgetting as the weakening or "punishing" of memory associations when they are incorrectly retrieved. Real-life Example: You might remember a party vividly but forget a specific conversation your friend insists happened. This may reflect weakened links between associated elements due to later experiences fragmenting the original memory. Core Idea: Melton & Irwin (1940) proposed that when a memory (target) is mistakenly retrieved (e.g., old email password), its association with a cue (e.g., "password") gets weaker. Repeated retrieval of the wrong memory (e.g., old password) further weakens the cue-target bond, eventually making it less likely to be retrieved. Implications: Explains retroactive interference: newer experiences weaken earlier memory associations. Explains retrieval-induced forgetting: during retrieval, competing items that intrude can be punished and weakened. Comparison with Blocking: Blocking: Forgetting happens because strong competitors dominate access to a cue. Unlearning: Forgetting happens because the correct memory's association with the cue is weakened. Both are integrated in the two-factor model of retroactive interference (Melton & Irwin, 1940). Challenges: Hard to prove unlearning because it's difficult to show a memory is permanently gone (as opposed to just inaccessible). Some evidence suggests merely strengthening competitors (blocking) may not fully explain forgetting—supporting the need for another mechanism like unlearning. Conclusion: Associative unlearning suggests that forgetting can result from weakened cue-target links due to interference from other memories. It works alongside blocking, but both may be insufficient alone—leading to consideration of inhibitory processes as another cause.

Answer 13

Inhibition as a Cause of Forgetting – Summary for Revision Inhibition theory suggests that forgetting occurs because the brain actively suppresses competing memories to reduce distraction and improve focus on the memory being retrieved. 🔑 Core Concepts Why Inhibition? Competing memories (like old phone numbers or words) can disrupt retrieval. Inhibition reduces the activation of these competitors, helping retrieve the target memory. Key Analogy: Like trying to stop a habitual action (e.g., checking a broken watch), the brain may inhibit a memory that’s no longer relevant (e.g., old password) to prevent it from interfering. 🧠 Inhibition vs. Other Theories Not unlearning: The cue-target link remains intact; it's the target itself that’s suppressed. Not blocking: Doesn't require strengthening a competitor; rather, it's about reducing interference through attentional control. 📚 Key Findings from Retrieval-Induced Forgetting (RIF) Cue Independence: Forgetting spreads to other cues (e.g., can’t recall BANANA even when cued with MONKEY instead of FRUIT). Retrieval Specificity: Forgetting only occurs with retrieval, not restudy (e.g., practicing retrieval of ORANGE harms BANANA, but restudying ORANGE does not). Strength Independence: Forgetting doesn't require that the practiced memory be strongly learned. Even failed retrieval attempts can cause forgetting (Storm et al., 2006). Interference Dependence: Highly accessible competitors (e.g., BANANA) are more likely to be inhibited than weak ones (e.g., GUAVA). Attention Dependence: Divided attention (e.g., during multitasking) during retrieval eliminates RIF (Román et al., 2009). ADHD individuals and stressed participants also show reduced RIF. 🧪 Neuroscience Evidence Brain Imaging (Kuhl et al., 2007): During early retrieval attempts, prefrontal cortex and anterior cingulate cortex are highly active (high interference). Later retrievals require less effort — inhibition reduces interference over time. Greater decline in brain activation = greater forgetting of competitors. Cortical Pattern Suppression (Wimber et al., 2015): Brain activity patterns tied to competing memories are suppressed with repeated retrieval. 🐀 Animal Studies Rats also exhibit RIF (Bekinschtein et al., 2018): Selectively reviewing one object causes forgetting of the other. RIF in rats shares properties with humans: cue independence, retrieval specificity, etc. Inactivating prefrontal cortex abolishes RIF — showing shared neural mechanisms. 🧠 Conclusion: Inhibition Is Adaptive Forgetting helps reduce interference and allows better focus. It is goal-directed, attention-dependent, and neurobiologically supported. As Bjork suggests, forgetting can be beneficial if the memory is irrelevant or can be reactivated when needed.

Answer 14

A Functional View of Incidental Forgetting — Summary for Revision Historically, psychologists viewed forgetting as a passive process, caused by contextual fluctuations, inappropriate retrieval cues, and interference (e.g., blocking). These factors were thought to affect us externally and uncontrollably. However, a new perspective has emerged: forgetting can be active and adaptive. Evidence across molecular, neurological, and behavioral studies shows that species may have evolved mechanisms that purposefully facilitate memory loss for functional reasons, such as undoing synaptic plasticity (e.g., Davis & Zhong, 2017). A key mechanism is inhibition: to resolve competition during retrieval, the brain suppresses competing memories. This suppression (or forgetting) makes target retrieval easier and reduces future interference. This adaptive forgetting supports cognitive control and behavioral flexibility, allowing us to focus on relevant memories while ignoring outdated or irrelevant ones. Therefore, forgetting isn't always a failure—it's often a positive and necessary part of a well-functioning memory system.

Answer 15

Forgetting increases over time, though not at a constant rate. The function relating forgetting to time is known as a forgetting curve, and it follows a logarithmic function. At the same time, synaptic and systemic consolidation processes make memories more resilient over time, though consolidated memories sometimes need to undergo reconsolidation when reactivated. Repeated retrieval of memories slows their forgetting The availability of a memory in the system (i.e., whether it remains in storage) must be distinguished from its accessibility (i.e., whether one can retrieve it). Permanent memory loss is very difficult to establish through behavior, as lack of availability and inaccessibility both predict memory failure. Neurobiological mechanisms actively degrade consolidated synaptic connections reducing the availability of a memory over time and confirming the existence of a decay process, even if this may be hard to establish behaviorally. The generation and integration of new neurons in the hippocampus throughout life structurally remodels hippocampal networks in a way that induces forgetting, a phenomenon known as neurogenesis-induced forgetting. This form of forgetting doesn't erase older memories, but may render them inaccessible, and likely forms the basis of infantile amnesia. Other factors correlated with time (apart from decay) make potent contributions to the forgetting function, including interference, inhibition, and fluctuations in physical and mental context. Interference arises when the retrieval cues used to access a memory becomes associated to other experiences that compete for access to conscious awareness. The more competitors that are attached to a cue, the worse recall of any one item becomes, a generalization known as the cue overload principle. When previously learned experiences (or knowledge) disrupt retention of more recently acquired experiences, it is known as proactive interference. When more recently acquired experiences (or knowledge) disrupt retention of previously acquired experiences, it is known as retroactive interference. When one has learned a set of material, presenting part of the set as cues for the recall of the remainder typically impairs the ability to recall the remainder, a phenomenon known as part-set cuing impairment. The very act of remembering can cause forgetting, a phenomenon known as retrieval-induced forgetting. Retrieval-induced forgetting happens when one tries to selectively retrieve some memories associated to a cue, a process which generally impairs the remaining associates. Blocking theories attribute interference to the tendency for stronger traces to persistently intrude during retrieval of weaker ones, leading the person to abandon search. Unlearning theories propose that interference causes destructive changes to the associations that underlie a trace, as a result of learning mechanisms that punish inappropriate retrievals. Inhibition theories propose that forgetting arises from the suppression of interfering traces by inhibitory mechanisms that resolve competition. Research using the retrieval-induced forgetting paradigm has provided specific evidence supporting the existence of inhibition. Retrieval-induced forgetting exhibits key functional properties that favor the involvement of inhibition, including interference-dependence, cue-independence, strength-independence, retrieval-specificity, and attention-dependence. Retrieval engages cognitive control processes mediated by the ventrolateral prefrontal cortex that have been linked to the suppression of interfering memories and the induction of retrieval-induced forgetting. Retrieval-induced forgetting is a species-general phenomenon and can be abolished by selective lesions to the rodent prefrontal cortex. Forgetting may often be adaptive, if it reduces demands on cognitive control processes that would otherwise be needed to suppress interference from competing memories. Thus, adaptive forgetting may increase cognitive efficiency Research on memory at all levels of analysis (molecular, brain systems, cognitive) is increasingly revealing the active and functional nature of forgetting, with evidence accumulating that nature has evolved dedicated mechanisms to undo memories.

lecture 19 - incidental forgetting Flashcards

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