Human Memory and Learning Exam 3

false memories

• memories that don’t correspond to events as they actually happened

• experienced as a memory, not a lie/imagined events

• not all false memories are equal

  • incorrect detail from real events

  • incorporation of second-hand experiences into own memory

  • inability to distinguish between imagined/real events

  • falsely remembering event that didn’t happen

importance of false memories

• high stakes situations → false/erroneous memories can cause an innocent person to be jailed or a guilty person to be freed

• eyewitness testimony often considered gold standard in legal system/very compelling to juror’s perspective

• about 70% of wrongful convictions overturned by DNA evidence involved in mistaken eyewitness testimony

subtle wording manipulations

• loftus/palmer (1974)

  • the degree of impact suggested by the question was linearly related to the speed participants estimated cars were traveling

  • clear implications for way which the police/lawyers question victims, eyewitnesses, those accused

• mccloskey/zaragoza (1985)

  • participants in misleading group more likely to select misleading item when available; normal performance when it was a new word

• loftus/zanni (1975)

  • the difference between “a/the” more than doubled the likelihood that the participant will report having seen something they didn't

• important that researchers/people from legal world choose their words carefully

misinformation effect

• result of presenting post-event misinformation about a witnessed event that can obscure, change, degrade memory of original event

• most robust findings un memory research

• timing of misinformation is important:

  • significant increase in retrieval of misleading narrative information only when the narrative is closely followed encoding episode

  • demonstrates how powerful misinformation effect is and how important misinformation is delivered shortly after the target event takes place

• self-generated misinformation (Zaragoza et al., 2001)

  • giving positive feedback to the incorrect information you yourself made led to more false memories

trace impairment

• explanation for misinformation effect

  • original memory traced altered by misinformation

coexistence hypothesis

• explanation for misinformation effect

  • one memory trace for real event, second for the misinformation event + another new trace for each retrieval of the real event

imagination inflation

• merely imagining an event increases the likelihood that you will falsely remember it happening to you

false memory induction

• loftus/pickrell (1995) and loftus et al. (1996)

  • false memories for events are induced in adults by repeatedly asking then about childhood events they never experienced

  • participants asked about a time they were lost in the mall as a child (didn’t happen)

    • if a participant couldn’t remember, experimenter pushed them into it

    • 25% of participants reported they remembered event/provided specific details

      • leading questions, imagination, social pressure

weapon focus

• focus on a weapon at the expense of other things in the environment/on the person

  • individuals who witness crimes necessarily experience high level of arousal

  • high arousal often combined with/ weapons focus

• Maass/kohnken (1989)

  • presence of a dangerous object increased false recognition of confederate

anatomy of a false memory

• differences in brain activity associated w/ true vs. false memories

• hippocampus, parahippocampal cortex, medial/lateral prefrontal cortex

• false memories thought to be a failure to inhibit the misinforming memory

  • hippocampus/parahippocampus → recollection

  • prefrontal cortices → control over thoughts

metacognition

• thinking about thinking; knowing what you know and don’t know

  • our knowledge/awareness of our own memory processes, introspective awareness of our own memory abilities

metamemory

• our knowledge and awareness of our own cognitive processes

metamemory: monitoring

• part of metamemory

  • refers to our ability to reflect on and become aware of what we know/don’t know

  • confidence in our memory

  • knowledge about sources of our memory

  • judgements about whether we’ll be able to recall something from the past

  • judgements about whether we think we’ll remember something in the future

metamemory: control

• part of metamemory

  • refers to our ability to regulate our learning/retrieval (update, change, improve, etc.)

  • if output of metamemory minoring at the time of retrieval suggests you could access a memory, then you can control whether/how you engage in the active search

  • if monitoring suggests that you have not learned something well, you can exert control to study longer

judgements of learning

• metamemory at encoding

  • judging how well you’re learning it at time of encoding

  • predictions about future memory performance

  • can also be thought of as an important monitoring process that contributes to self-regulated learning

  • while learning, we make implicit judgments of learning that influence how we engage w/ a given item and where we dedicate additional time to encode it

    • cue-target learning and cue-only learning

determining accuracy

• dunlosky/nelson (1994)

  • participants encoded cue-target Paris using either imagery (deep) or rote rehearsal (shallow)

    • group 1: JOL immediately after ending

    • group 2: JOL after delay

  • results

    • immediate JOLs are not sensitive to levels of processing and are inaccurate (WM)

    • delayed JOLs are sensitive to levels of processing and accurate (LTM)

neural basis of jols

• kao et al. (2005)

  • subsequent memory paradigm w/ fMRI

  • scanned encoding

  • unscanned retrieval

  • JOLs for scenes

  • medial temporal lobe most active for scenes that were later remembered

    • MTL is what they actually remember

  • ventromedial/dorsomedial prefrontal cortex most active for scenes participants predicted they would remember vs. scenes they predicted they would forget

    • VM/DMPFC is what they’re predicting

• participants who made more accurate JOL predictions showed greater activity in VMPFC than participants who made inaccurate predictions

  • suggests that VMPFC may support JOLs

• activity in left lateral PFC is sensitive to both memory/JOL accuracy

amnesia

• pathological loss of memory, usually due to brain damage/dysfunction

• often sudden onset (hypoxia, injury, surgery, infection, medications)

• severe memory impairment (other cognitive function; language, intelligence, attention) negatively spared

• daily functioning moderately preserved w/ support/external aids

dementia

• symptom of a disorder/disease (not a diagnosis on its own)

• gradual, acquired cognitive decline

• multi-domain cognitive deficits beyond memory (language, attention, executive function, visuospatial abilities, social cognition)

• progression loss of independence in everyday activities

anterograde amnesia

• inability to form new memories (after damage)

retrograde amnesia

• inability to retrieve old memories (before damage)

amnesic syndrome

• characterized by anterograde amnesia that makes it difficult and impossible to encode new episodic and semantic memories

  • intact WM

  • intact implicit memory

  • intact procedural memory

  • impaired EM

  • impaired SM

mtl/declarative memory system

• all structures in medial temporal lobe (MTL) contribute to declarative memory, so damage to any structure in this system should produce a declarative memory deficit

• role of hippocampus in EM consolidation is time limited, w/ these memories consolidated to cortex over time

• system independent of other aspects of cognition including perception, WM, non-declarative memory

• first aspect of this theory suggests that there is no way to dissociate EM/SM in individual w/ MTL damage

E/S memory in amnesia

• developmental amnesia (children w/ damage to MTL)

  • for a long time, it was thought that they would be unable to learn declarative information (E/S) and would therefore have profound developmental delays

  • vargha-khadem et al. (1997)

    • neuroanatomical specificity of brain damage remarkable in that their bilateral hippocampi are compromised but surrounding neocortical structures (perirhinal, entorhinal, parahippocampal) are intact

    • in line w/ academic achievements and general ability to get by in daily life, they have SM abilities that are within normal range

    • profound episodic deficits by intact SM

    • apparent division of labor in MTL, such that hippocampus is not required for all forms of declarative memory

recollection

• recognition memory that’s associated w/ retrieval of contextual details from previous encounters (“I remember”)

  • requires recovery of link between retrieval cue and specific past episode

familiarity

• recognition memory that is based on stimulus itself, i.e., not retrieval of contextual information (“I know”)

  • feeling that the cue is old but not the link to specific episodic

recollection vs. familiarity

• yonelinas et al. (2002)

  • c = controls

  • h+ = MTL damage that affects the hippocampus/MTL cortex

  • h = MTL damage that affects the hippocampus only

  • deficits limited to recollection

• Eldridge et al. (2000): healthy adult fMRI study

  • hippocampus shows increased activity for “remember” responses but not “know”

  • MTL cortical areas show increased activity for “know” but not “remember”

recall vs. recognition

• mayes et al. (2002)

  • patient w/ selective hippocampal damage (Y.R.)

  • deficits on free-recall tests

  • intact performance on recognition-memory tests

  • findings relate to familiarity/recollection

    • recall tasks can be solved only by recollective processing,

    • recognition tasks (i.e. when you have the stimulus right in front of you) can be solved by either familiarity or recollection

Korsakoff’s syndrome

• primarily affects thalamic nuclei and mammillary bodies

• severe amnesia caused by chronic alcoholism (vitamin B1 deficiency)

• anterograde amnesia

• retrograde amnesia

• anosognosia → lack of awareness of memory problems

• confabulation → believed lies due to source monitoring deficit

electroconvulsive therapy

• individuals w/ severe depression may be treated w/ ECT

• powerful electric shock to the head

• temporary retrograde amnesia is a side effect

• loss of episodic and semantic memories from previous 1-2 years

dementia types

• alzheimer’s disease

• vascular dementia

• frontotemporal dementia (ftd)

• lewy body dementia

• mixed dementias

alzheimer’s disease

• most common cause of dementia

vascular dementia

• related to strokes, small vessel disease; often stepwise decline

frontotemporal dementia (ftd)

• early changes in personality, behavior, language

Lewy body dementia

• visual hallucinations, Parkinsonism, fluctuating cognition

mixed dementias

• combinations of pathology (ex: Alzheimers and vascular)

amyloid plaque

• accumulation of proteins in spaces between neurons

• disrupt communication across neurons

• trigger immune response that results in inflammation/death of surrounding neurons 

neurofibrillary tangles

• Tau proteins contribute to structural integrity of neurons and allow for the intracellular transport of essential compounds

• in AD, Tau proteins collapse inside neurons and cause cell death

progression of neuropathology in alzheimer’s

• brain changes lead behavioral changes, often by several decades

• makes it difficult to detect early-stage AD (post-mortem or CSF sampling w/ spinal tap)

• pharmacological interventions have proven ineffective, but typically only administered after behavioral changes

• early detection likely key to successful intervention

• early-stage

  • earliest neuropathological changes affect the MTL/posterior cingulate (structure at the bottom of the frontal lobe)

  • thought that these changes begin to emerge as many as 20 years before meeting diagnostic criteria

  • complaints: mild forgetfulness

• mild to moderate

  • may span 2-10 years

  • neuropathology extends to frontal lobes, posteriorly thorough temporal lobe, into medial parietal areas

  • more pronounced cognitive problems

    • EM, aggression, reasoning, word finding, inhibition, disorientation

• late-stage

  • life expectancy 1-5 years

  • neuropathology extends throughout entire brain

  • profound and global cognitive declines

    • unable to recognize family

    • unable to care for self/communicate

AD/identity

• addis/tippett (2004)

  • 20 individuals w/ AD, 20 age-matched controls

  • autobiographical interview to assess E/S retrieval in autobiographical memory

  • questionnaire used to measure identity

  • results

    • patients w/ AD showed deficits in retrieving S/E details from their personal past

    • problem was most apparent for recent life events: graded retrograde amnesia

    • AD patients showed changes in several aspects of their identity (personal family, social, moral)

      • consistent w// reports from caregivers of patients

    • degree of impairment in recalling episodic details in the autobiographical interview was associated with/ magnitude of identity loss

      • not just about memories, but also sense of identity and the loss of it

capgras syndrome

• delusional misidentification: beliefs that a person, place, or thing has changed identity

• delusional beliefs: unsubstantiated by reality, not shared by other people, resistant to counter-evidence and counterarguments

• when in relation to well-known people (ex: loved ones) referred to as this

  • belief that a loved one is an imposter often deepens over time and these interactions become increasingly aggressive

• historically thought to be a psychiatrist illness (ex: schizophrenia) but can be observed in other dementias

• what usually happens in a typical human:

  • autonomic nervous system contributes to our affective (emotional) state

  • sympathetic branch induces an arousal response

  • cognitively, this arousal is interpreted as a “feeling of familiarity”

• what happens here:

  • this system is not getting turned on

  • reduced autonomic responses in this

    • skin conductance response not that different between familiar and unfamiliar

    • face processing in brain is decoupled from autonomic system

    • no “feeling of familiarity”