Retrieval and use of explicit memories is directed by the frontal lobes, acting as a working memory or executive function.
Encoding and storage of explicit memories is facilitated by the hippocampus.
The hippocampus holds events and facts temporarily (a couple of days) before consolidation, which involves moving the memories to other parts of the brain for long-term storage.
Consolidation largely occurs during sleep.
Explicit/declarative memories include facts, stories, and meanings of words (e.g., first time riding a bike, facts about bicycles).
Without the hippocampus, forming new explicit memories is impossible.
Ways to Measure Explicit Memory
Recall: The ability to retrieve and reproduce previously encountered material from memory.
Recognition: The ability to identify previously encountered material.
Recognition is generally easier than recall in tests of explicit memory.
Implicit Memory Processing
Implicit memories include skills, procedures, and conditioned associations.
The cerebellum (little brain) forms and stores conditioned responses; phobic responses can be stored this way even without conscious recall of how the fear was acquired.
The basal ganglia, near the thalamus, controls movement and forms/stores procedural memory and motor skills (e.g., riding a bicycle, even if the lesson itself isn't recalled).
Implicit/nondeclarative memory includes procedural motor skills (tying shoes), classically conditioned emotional responses (CERs) like fears and prejudices, and priming.
Priming: Exposure (often unconscious) to previously stored information predisposes our responses to related stimuli.
Research on subliminal perception shows that unconscious stimuli can reach our brains and prime us to recall related information more easily or with more difficulty.
Example: Seeing "red" and "fire engine" primes quicker recognition of the word "apple".
Improving Long-Term Memory
Retrieval Cue: A clue or prompt that helps stimulate recall or retrieval of a stored piece of information from long-term memory.
Elaborative Rehearsal: A technique for improving memory by linking new information to previously stored material; also known as deeper levels of processing.
Effective Encoding
Accurate encoding is crucial for remembering information well.
Automatic Encoding: requires no effort.
Effortful Encoding: requires work and attention.
Rehearsal and Distributed Practice
Spacing Effect: Retention and recall are better when study time is spread out over shorter sessions.
Longer intervals between study sessions lead to better long-term retention and require fewer sessions.
Testing Effect: Distributed practice that includes testing or answering questions about the material leads to better learning and retention than rereading alone.
Massed Practice: Cramming information all at once is not time-effective.
Making Information Personally Meaningful
Memorizing meaningful material takes significantly less effort compared to nonsense syllables.
Actors memorize lines more easily by understanding the feelings and meanings behind the words.
Self-Reference Effect: Relating material to ourselves aids encoding and retention.
Deeper Processing and Elaborative Rehearsal
Rehearsal from practice testing and distributed practice is most effective for improving LTM and exam scores.
Maintenance rehearsal (repeating information) can hold information in STM for about 30 seconds.
Storage in LTM requires deeper processing, like elaborative rehearsal (making new information meaningful).
Example: Using the acronym “Roy G. Biv” to remember the colors of the rainbow.
Students taking notes on laptops tend to transcribe lectures verbatim (shallow processing), while students taking notes on paper reframe the material (deeper processing), leading to better conceptual understanding.
Mnemonics
Strategies and tricks for improving memory, such as verses or formulas.
Mnemonics can enhance retention but may be ineffective or counterproductive for ordinary memory tasks if too complex.
Example: ROYGBIV is an acronym for the colors of the rainbow.
More About Mnemonics!
Method of Loci: Greek and Roman orators imagined parts of their speeches attached to places in a courtyard to keep track of their long speeches.
Peg Word: memorize a set of 10 images that you can use as “pegs” on which to hang ideas.
Read, Recite, Review
Effective Technique:
Read the passage.
Close the book and hide your notes.
Write down (or say out loud) everything you can recall.
Review what you’ve read to check understanding and memory.
Ineffective Technique:
Rereading a textbook passage until you think that you’ve “got it”.
Memory Storage: Capacity and Location
The brain is not like a hard drive; memories are in overlapping neural networks, not isolated files.
The brain’s long-term memory storage does not get full; it gets more elaborately rewired and interconnected.
Memories are not files found in single locations.
The process of physically storing a memory in your brain is called consolidation.
Context-Dependent Memory
Part of a memory's web of associations is the context in which it was formed.
Memory retrieval is easier when in the same context as when the memory was formed.
Example: Sitting down and opening a psychology book might bring back forgotten concepts.
Words learned underwater are better retrieved underwater.
State-Dependent Memory
Memories are linked to the emotional state we were in when we formed the memory.
Mood-Congruent Memory: The tendency to selectively recall details that are consistent with one’s current mood.
This biased memory reinforces our current mood.
Memories can be linked to physiological states.
Eidetic Memory
The word eidetic refers to extraordinarily detailed and vivid recall, particularly of visual images.
It comes from the Greek word εidos (pronounced [ê dos, eidos, "seen"]).
It is a medical term, popularly defined as the ability to recall images, sounds, or objects in memory with extreme precision and in abundant volume.
Super Autobiographical Memory
Hyperthymesia is a mental condition that allows a person to remember almost every detail of their lives with near-perfect accuracy.
Brain Areas Associated with Memory
Prefrontal Cortex (and parts of temporal lobes): Efficient encoding of words, pictures
Cerebellum: Formation, retention of simple classically conditioned responses
Cerebral Cortex: Storage of long-term memories, potentially in areas involved in the original perception of the information
Amygdala: Formation, consolidation, retrieval of emotional memories
Frontal Lobes: STM and working memory tasks
Hippocampus: Formation of declarative memories; retrieval of memories; may bind together elements of a memory for later retrieval
Tip-of-the-Tongue (TOT) States
Information in long-term memory is organized by the way words sound and look.
Tip-of-the-tongue states can occur when trying to recall names, objects, places, etc.
Forgetting
Forgetting is adaptive because it allows us to prioritize important memories.
Causes of forgetting:
Brain damage
Encoding failure
Storage decay
Retrieval failure
Interference
Motivated forgetting
Why We Forget
Forgetting is adaptive and necessary for efficient memory.
Decay
Decay Theory: Information in memory eventually disappears if it is not accessed.
Applies more to short-term than long-term memory.
"Use it or lose it!"
Interference Theory
Retroactive Interference: Newly learned information makes people forget old information.
Proactive Interference: Old information makes people forget newly learned information.
Always study for your hardest or most important class last. Then go to bed, so nothing interferes with what you have just studied.
The Repression Controversy
Repression: The psychodynamic explanation of traumatic amnesia involves the selective, involuntary pushing of threatening information into the unconscious.
Concepts lack good empirical support.
There is skepticism about the validity and accuracy of “recovered memories.”
Critics argue that therapists may encourage false memories of victimization through suggestion and confabulation.
The Brain and Memory
Damage to various brain areas can affect encoding, storage, and retrieval of memories.
Biological Causes of Memory Loss: Alzheimer’s Disease
Alzheimer's Disease leads to an extreme decrease in explicit/declarative memory.
Patients retain some implicit/nondeclarative memory.
Brains show tangles from degenerating cell bodies and plaques from degenerating axons and dendrites upon autopsy.
Infantile Amnesia
Implicit memory from infancy can be retained (skills, conditioned responses).
Explicit memories only go back to about age 3 for most people; this is called infantile amnesia.
Explanations:
Encoding: Memories were not stored well because the hippocampus is one of the last brain areas to develop.
Forgetting/retrieval: The adult mind thinks more in a linear verbal narrative and has trouble accessing preverbal memories as declarative memories.
Before age 3, individuals lack a fully developed theory of mind (understanding others' identities) and object permanence (understanding objects exist even when not seen), which are necessary for building retrievable narratives.