Memory

Memory

retention of information taken in by our senses

Memory and Perception

• brains go beyond the available information to make sense of the world

  • sometimes leads to filling in the gaps

  • makes us prone to errors

Reconstructive Memory

• when remembering we actively construct not passively recall information

• memory includes a manufactured perspective which does not exist, but made sense for the situation

  • seeing ourselves walking in third person

Three Types of Memory

1. Sensory

2. Short-term

3. Long-term

*differ in terms of span and duration

How does information move through the types of memory

1. Sensory

2. Short-term

   1. rehearsal

3. Long-term memory

4. back to Short-term (for recall)

Sensory Memory

• each sense has its own form of memory

  • Haptic → touch

  • Echoic → hearing

  • Iconic → seeing

  • Olfactory → smell

  • Gustatory → taste

Short-term Memory

• retains information for limited times

• holds the memories that we use when thinking or processing information

• very brief duration

  • 5-20 seconds

How do we lose information from short-term memory

• Decay

  • things fade over time

• Interference

  • loss of information due to competition with other information

  • Retroactive and Proactive

  • more likely to occur when information is similar

Retroactive Interference

• happens when learning new information interferes with prior knowledge

Proactive Interference

• happens when earlier learning gets in the way of learning something new

Short-term Memory Volume

• the span of short-term memory in adults is 7 (plus or minus 2) pieces of information

• can extend our short-term memory span by using chunking

Chunking

• organization of a large body of information into smaller more meaningful groups

Rehearsal

• repeating information

• extends the duration of short-term memory

• 2 types

  • maintenance and elaborative

Maintenance Rehearsal

• simply repeating the stimuli in the same form

Elaborative Rehearsal

• link stimuli to each other in a meaningful way

  • usually more effective

Levels of Processing

• ability to recall information is related to how deeply we process that information

1. Visual Processing

2. Phonological Processing

3. Semantic Processing

Visual Processing

• what the letters look like

  • most shallow

  • least effective

  • won’t remember for long

Phonological Processing

• what the words sound like

  • more effective

Semantic Processing

• what the sentence means

  • most effective

  • remember for longer

  • give actual meaning to the words

Why can’t we remember things from early infancy?

• our brains are still developing

  • no capacity for memory

• we don’t have language to make meaningful connections

• we don’t have enough experience to build new memories

Long-term Memory

• includes facts, experiences, and skills that we’ve developed overtime

• may last decades or a lifetime (permastore)

Primacy Effect

• refers to our ability to remember stimuli presented first

Recency Effect

• refers to our ability to remember stimuli presented recently

Types of Long-Term Memory

• Explicit

• Implicit

Explicit Memory

• includes memories we recall intentionally and of which we have conscious awareness

Types of Explicit Memory

• Semantic

• Episodic

Semantic Memory

• general knowledge

  • historical facts

  • geography

  • science

Episodic

• recollection of events in our lives

Implicit Memory

• includes memories we don’t deliberately remember or reflect on consciously

Types of Implicit Memory

• Procedural

• Priming

• Habituation

• Conditioning

Procedural Memory

• memory for how to do things

  • includes motor skills and habits

Priming Memory

• ability to identify a stimulus more easily or more quickly after we’ve encountered similar stimuli

Encoding Memories

• encoding is getting information into memory

• in order to encode we must first attend to it

• most events we experience are never encoded in the first place

• next-in-line effect and memory for common objects

Mneumonics

• helpful in learning new information

  • rhymes

  • songs/music

  • method of loci (overlay information on internal map)

• involve linking new information to meaningful concepts already stored in long-term memory

Storage

• keeping information in memory

  • depends on our interpretations and expectations

Schemas

• organized knowledge structures or mental models that we’ve stored in memory

  • can be useful in interpreting new situations but can also be misleading and lead to biases

Retrieval of Memories

• reactivation or reconstruction of experiences from our memory stores

  • not a perfect photograph

Retrieval Cues

• hints related to the original information

  • can help us to retrieve memories

3 Rs of Measuring Memory

• Recall

• Recognition

• Relearning

Recall - Measuring Memory

• generating previously remembered information

Recognition - Measuring Memory

• Selecting previously remembered information from an array of options

Relearning - Measuring Memory

• We relearn things we’ve already learned before faster than we learn things for the first time

Tip-of-the-Tongue Phenomenon

• retrieval failure

  • we are sure we know the information but we can’t remember what that information is

  • retrieval cues can help

Distributed vs Massed Practice

• distributed practice

  • study information in small increments over a large amount of time

• massed practice

  • study large increments over a brief period of time

*distributed practice is better than massed practice

Encoding Specificity - Context-Dependent learning

• superior retrieval when the encoding context matches the retrieval context

Encoding Specificity - State Dependent Learning

• superior retrieval of memories when the physiological or psychological state is the same as it was during encoding

Long-term Potentiation

• gradual strengthening of the connections among neurons from repetitive stimulation

  • plays a key role in learning

Hippocampus

• plays a key role in forming memories

  • long-term

Where are memories stored in the brain?

• There is not just one place

  • different types of memories are stored in different brain regions

Glutamate role in memory

• glutamate binds to NMDA and AMPA receptors

  • increases firing rate of these neurons

    • leads to enhanced learning

Amnesia

• Often occurs following injury

• generalized amnesia following an injury is very rare

  • so is sudden recovery of memory

    • often times memory recovery is partial or absent

2 Types of Amnesia

Anterograde and Retrograde

Anterograde Amnesia

• the loss of ability to make new memories

Retrograde Amnesia

• loss of past memories

H.M.

• had radical surgery to treat severe epilepsy

  • chunks of temporal lobes including hippocampi were removed

• experienced mild retrograde amnesia and severe anterograde amnesia

  • implicit memory was intact

    • couldn’t learn new episodic/semantic information but could learn some motor skills

Clive Wearing

• Hippocampi were destroyed by a virus

  • caused complete anterograde amnesia

• showed priming effects

Destroying the Hippocampus…

• prevents explicit memory storage

• leaves implicit memory relatively intact

Emotional Memory

• amygdala and hippocampus interact to give us emotional memory

  • amygdala: helps recall emotions associated with fearful events

  • hippocampus: helps recall the events themselves

Hypophobia

• no emotional fear

  • often results in tragic deaths due to extreme risk taking

• fear is a very important defense mechanism

• caused by an issue with the amygdala/hippocampus

Erasing Memories

• some emotional memories are distressing and can manifest as PTSD

• pharmalogical treatments during memory recall may affect the emotional value of memory

  • drugs such as propanol may be effective at doing this

Can we always trust our memories

• no

  • they’re reconstructed and not perfect photos

  • not always accurate

Alzheimer’s Disease

• irreversible, progressive brain disease that slowly destroys memory and cognitive ability

• not part of normal aging

• fatal disease that affects the brain

• risk of developing AD increases with age

  • in most patients symptoms fist appear after age 60

Percentage of people with AD below 65

13%

Percentage of people with AD above 80

45%

4 Distinctive Features of AD brains

1. loss of brain volume

2. devastating losses of synapses and neurons within the hippocampus

3. overproduction of beta-amyloid plaques (dense deposits of protein and cellular material) that accumulate in the neuron

4. neurofibrillary tangles (twisted fibers, mainly Tau proteins) that build up inside neurons and kill them

Lifestyle Factors and AD

• people with active lifestyles are less likely to develop AD

• greater education and intellectual activity are related to lower rates of AD

• “use it or lose it” theory is attractive but difficult to prove

Memory Over Time

• changes as we age but shows the same basic processes throughout life

• children’s memories increase in sophistication

• memory span increases with age (until 12)

• conceptual understanding increases with age

• develop meta-memory skills

Infantile Amnesia

• inability of adults to retrieve accurate memories acquired before the ages of 2-3 years

Reason for Infantile Amnesia

• hippocampus is only partially developed in infants

  • sense of self is not established

• no evidence for use of hypnotic age regression or other techniques to beat this limitation

False Memories

• Flashbulb memories

• Imagination Inflation

• Source Monitoring Confusion

Flashbulb Memories

• emotional memories that are vivid and feel exceptionally detailed

  • accuracy declines over time

Imagination Inflation

• imagining an event inflates confidence on the likelihood that the event occured

Source Monitoring Confusion

• lack of clarity about the origins of a memory

• can cause numerous memory illusions

  • including cryptomnesia

Cryptomnesia

• failure to recognize that our ideas originated somewhere else

Suggestive Memory Techniques

• procedure that encourages patients to recall memories that may or may not have taken place

Misinformation Effect

• creation of fictitious memories by providing misleading information about an event after it takes place

• eg, lost in the mall study

Lost in the Mall Study

• experimenter adds elaborate story about being lost in the mall to a list of real childhood experiences

• participant believes the memory is real and even adds new details

Eyewitness Testimony (Forensic Psychology)

• confidence and accuracy are not strongly correlated

• many wrongful convictions are due to inaccurate eyewitness testimony

False Memory Controversy

• psychotherapy and child abuse

  • suggestions of abuse can lead to false memories of abuse