CP Lecture 5 - Implicit and False Memory

How does priming work in reference to a spreading activation network?

Priming is the "implicit activation of concepts in long-term memory."

In a semantic network, concepts (nodes) are linked together. When one concept (e.g., "doctor") is presented, its node becomes active. This activation then spreads to all related nodes (e.g., "nurse," "hospital," "sick").

This makes the related concepts "primed," meaning they can be retrieved or processed more quickly and easily than unprimed concepts.

• Example: After hearing "river, flow, boat," you are more likely to interpret the ambiguous word "bank" as a river bank, not a financial bank.

Procedural Memory

Procedural Memory is a type of implicit memory (nondeclarative, unconscious) for "how to do things."

It is the memory for motor skills, habits, and tacit (unspoken) rules.

• Examples: Riding a bicycle, tying your shoelaces, playing a musical instrument, or mirror-tracing.

• Features: It is not "one-trial" learning; it is learned gradually through incremental experience and practice.

What are three possible reasons procedural memory is so hard to verbalise (nondeclarative)?

• Different Neuroanatomy: It may rely on entirely different brain structures (e.g., the basal ganglia) than the declarative memory system (which relies on the hippocampus).

• Original Format: We may not have a way to translate the original format of the skill (which is muscle commands and motor procedures) into verbal, declarative language.

• Learned Incrementally: The skill was never encoded as a set of verbal facts to begin with. It was built up gradually through doing, not through conscious thought or verbal instruction.

Explicit Memory Test 

• Definition: A test that consciously and directly asks you to "remember" information from a previous learning episode.

• Examples:

  • Free Recall: "Write down all the words from the list you just saw."

  • Cued Recall: "What word on the list was a type of fruit?"

  • Recognition: "Was 'apple' on the list? Yes or No."

Implicit Memory Test

• Definition: A test that measures the influence of a past experience without asking you to consciously remember it.

• Example: Stem Completion.

How is a stem completion task used to measure implicit memory (priming)?

It measures memory as an increase in performance (priming).

1. Phase 1 (Study): Participants see a list of words (e.g., assassin, mystery).

2. Phase 2 (Test): Participants are given a list of three-letter word "stems" and are told to "complete them with the first word that comes to mind."

   • ass______

   • mus______

   • mys______

   • cou______

• Measurement: Implicit memory (priming) is demonstrated if participants complete the stems with words from the study list (e.g., assassin, mystery) more often than participants who never saw the study list. They do this even if they have no explicit memory of seeing the word.

What are three dissociations (distinct features) that show implicit memory is different from explicit memory?

A "dissociation" is when a variable has a different effect on implicit vs. explicit memory.

1. Levels of Processing:

   • Explicit: Deeper processing (e.g., rating words for meaning) leads to much better explicit recall.

   • Implicit: Deeper processing has no effect. Priming is just as strong for words processed at a shallow (visual) level.

2. Modality/Format Change:

   • Explicit: Changing the format (e.g., study ASSASSIN, test assassin) has little effect on explicit recall (you still remember the concept).

   • Implicit: Changing the format dramatically reduces priming. Implicit memory is highly specific to the perceptual details of the original stimulus.

3. Delay (Duration):

   • Explicit: Explicit memory (recall) declines steadily and significantly over time.

   • Implicit: Implicit memory (priming) is much more durable and can last for a long time with very little decay.

Describe the DRM (Deese-Roediger-McDermott) paradigm and its usual findings.

• Paradigm: Participants study lists of 15 words that are all semantically associated with a single, non-presented "critical lure" word.

  • Example List: bed, rest, awake, tired, dream, snore...

  • Critical Lure (Not Shown): sleep

• Usual Finding: In a subsequent memory test, participants falsely recall (and are very confident about remembering) the critical lure word (sleep) almost as often as they correctly recall the words that were presented.

• Explanation: This is thought to be a side-effect of spreading activation. As each list word is presented, it spreads activation to the central concept (sleep), which becomes so highly activated that the brain misattributes this activation as an "experienced memory."

Describe Kim Peek's unique memory ability and his conceptual flaw, especially in relation to the DRM paradigm.

• Ability: Kim Peek was a savant with a "mega-memory." He had near-perfect, verbatim recall of every book he had ever read.

• Conceptual Flaw: He had an extremely poor conceptual (semantic) memory. He could not understand metaphors, abstract ideas, or the gist of what he read. He had all the "dots" (facts) but could not "connect" them.

• DRM Relation: Kim Peek would be immune to the DRM illusion. Because his semantic network was so poorly connected, presenting the list words (bed, rest, tired) would not cause activation to spread to the critical lure (sleep). He would recall only the exact words on the list, demonstrating his memory was purely episodic and lacked the semantic connections that cause false memories in the rest of us.

Flashbulb Memory

• Definition: A flashbulb memory is a highly vivid, detailed, and long-lasting memory for the circumstances in which you first heard about a shocking, highly emotional, and consequential public event.

• Example: A person's memory of where they were and what they were doing when they learned about the 9/11 attacks or the death of a major public figure.

• Why Study Them: These events (like 9/11) provide a unique "natural experiment." Everyone learns about the event at the same time, allowing psychologists to track the accuracy and confidence of these emotional memories over long periods (years) and compare them to "ordinary" memories.

How are flashbulb memories similar to and different from ordinary memories?

• Similarity (Accuracy): Flashbulb memories are NOT more accurate. They decay at the exact same rate as ordinary memories. The number of consistent details declines over time for both. * Difference (Confidence): People's belief in the accuracy of their flashbulb memories remains extremely high over time, while their confidence in ordinary memories declines.

• Significance: This shows that the "flashbulb" is an illusion of confidence and vividness, not a "snapshot" of perfect accuracy. The emotional importance makes us feel like the memory is perfect, even as it decays.

What were the key findings of Conway et al.'s (2009) flashbulb memory study (of 9/11)?

Conway's study tracked memories over 3 years.

• Key Findings:

  • Flashbulb memories were found, and they were stable (consistent) for many participants, especially those who were more personally affected.

  • Best Remembered Facts (Most Consistent): Factual details about the event itself (e.g., "Where were you...").

  • Worst Remembered Facts (Least Consistent): Details about the emotional response (e.g., "What time did you learn about these events?").

• Confidence: Similar to Talarico & Rubin, participants who were inconsistent (their memory changed) were almost as confident as those who were consistent, showing a clear disconnect between confidence and accuracy.

Infantile Amnesia

• Definition: The inability of adults to retrieve genuine episodic memories from the first 2-3 years of their life.

• Possible Explanations:

  1. Brain Development: The hippocampus (crucial for forming episodic LTM) is immature at birth and develops over the first few years.

  2. Lack of Schemas/Language: As infants, we lack the complex schemas (understanding of the world) and the language structure needed to encode and organize our early experiences in a way that can be retrieved later in life.

  3. Neurogenesis: The high rate of new neuron growth in the infant hippocampus may disrupt and "overwrite" the circuits that store old memories.

Reminiscence Bump

The Reminiscence Bump is a finding in memory research that when adults (especially those over 40) are asked to recall autobiographical memories, they show a disproportionately high number of memories from the period of their adolescence and early adulthood (approx. ages 10-30).

This bump is a "reminiscence" that stands out from the expected pattern of childhood amnesia (few memories) and the recency effect (many recent memories).