Memory Errors- Lecture 6 Flashcards
Schacter (1999)
Classification of memory errors
> B locking: Inability to retrieve info although it
has been encoded deeply (tip of the
tongue feeling)
A bsent-mindedness: Memory errors due to
attentional failures at encoding or retrieval
M isattribution: Accurate memories assigned
to wrong source
B ias: distortion of previous experiences due
to present knowledge beliefs & feelings
P ersistence: Due to a negative experience
T ransience: forgetting of memories
S uggestibility : Memories which
incorporates inaccurate info from external source
Forgetting- LTM
DECAY
mnemonic traces simply fade away with time
Forgetting LTM
Interference
Proactive- previous info interferes
Retroactive- new info interferes with old memories
Forgetting LTM
Retrieval failure
Context dependency- cues in the environment that were present at encoding are no longer present- so fail to retrieve memory from storage
Directed forgetting- told that they can forget some of the information being presented to them
Rate of forgetting
- The rate we forget information is not linear
- Maximum loss of memory shortly after learning
- Memory loss is slower from there
Encoding leading to forgetting
Deficient encoding>forgetting
activity at encoding that predicts subsequent forgetting
Paller et al. (1988)
SUBSEQUENT MEMORY PARADIGM
Subsequently forgotten items produced more brain activity during encoding (when look back after recall test)
Kim (2011)
Meta analysis
Following areas showed subsequent forgetting effects across studies:
Temporoparietal junction
Posterior cingulate cortex and precuneus (
Ventromedial prefrontal cortex
-Default-mode network: network of areas that are active during resting state- like when mind wanders, or being focused on doing something else
Cabeza (2004)
Activation decreases are also critical for successful learning of new information- decrease means efficient reallocation of neurocognitive resources
Default-mode network
endogenous tasks - self referential task- default network is activated
exogenous tasks- external activities- Activity in the default-mode network may signal lack of attention or mind-wandering
Memory suppression
Directed forgetting
The item method
Interfering with encoding processes:
>After each item is presented at encoding, participants are asked to either remember or forget the preceding item
>At tests they are asked to retrieve all items and participants retrieve more remember than forget items
>effect found for pictures & words and in both recall and recognition tests suggesting»_space;deficits at encoding rather than difficulties at retrieval
Selective rehearsal hypothesis
People restrict elaborative processing of the Forget items
The encoding suppression hypothesis
Forgetting is an active process
There is more cognitive effort in Forget than Remember trials
Fawcett & Taylor (2008)
Evidence that reaction times to a secondary task is slower after Forget than Remember items (fewer resources available in forget trials because to forget uses additional processing)
Memory suppression
Directed forgetting
The list method
Interfering with retrieval processes
>2 lists are presented. At the end of the list and without expecting it, participants are asked to forget the preceding items
>At test, they are asked to retrieve all items
»»Retrieve more from the remember than the forget list
Effect is found only in recall (not recognition)»_space;»> the deficit affects locating the memory (i.e. retrieval).
Anderson et al (2004)
Think- No think
Not thinking about something remove it from memory? Potentially, as this affects the ability to remember it in the future:
>Forgetting increases (recall drops) with successive suppression attempts
Active inhibition of retrieval
Think No think contrast
Bilateral anterior hippocampi showed reduced activity during suppression trials
Showing increased activity during suppression:
- VLPFC\ both of these are required when subjects
- DLPFC/ need to override strong responses
- ACC
- IPS
Stress, memory and forgetting
Psychogenic amnesia
>emotional stressful events can cause amnesia affecting autobiographical memories
>no evident neurological cause
>can last a few hours- then usually memories are restored- but can still show amnesia from the time
Bias in remembering and forgetting
Pleasantness of a memory may affect how well we remember it
Bernsten (1996)
In a study of memory, 49% were pleasant and only 19% unpleasant
Sedikides & Green (2000)
Remember positive more than negative feedback
Does not extend to negative information/feedback directed towards others especially those we do not personally know
Sedikides & Green (2000)
Inconsistency-Negativity Neglect model
>we are motivated to neglect processing info that challenges our positive self-conceptions
> enables the stability of self concept
Own race face bias
Tend to remember faces of their own race better than faces of other races
>white people will struggle remembering faces of people of other races
False memory
Deese, Roediger & McDermott (1995)
Lured into thinking they remember something, with a series of words which are all highly associated with a lure word that is NOT studied.
»these memories were also judged to be as vivid and rich in contextual detail as any true memory
–These false memories can be more robust than true memory>increasing no. of related words
Roediger & McDermott (1995)
During encoding, the processing words which are semantically linked to a target word will also activate by association the target word
>Target word has been activated by a number of different words its overall activation level is high.
>Participants retrieve information on the basis of its activation strength
Theories of false memory:
Schacter (1999)
Gist memory & sensory reactivation
Word lists consisting of semantically related items >CREATES A GIST
-ptps rely on knowing the gist rather than individual features> make more semantically related errors
Cabeza et al. (2001)
fMRI study- recognise studied, related false and unrelated false words
>high levels of related false alarms
>Brain responses to related false items were almost identical to studied items in prefrontal and hippocampal sites.
>These areas were influenced by semantic similarity.
>Left Parahippocampal cortex activation- only area of difference: True>False memory
False memories:
Frontal amnesic patients
> Poor memory for true items but are also less likely to falsely recognise the related lures.
Pattern of results has been explained to result from a deficit in gist memory
also likely that item specific memory is also impaired in these patients
Verfaellie et al. (2004)
> frontal lobe damage is not linked to excessive number of false alarms and increased susceptibility to false memory
Social influence and memory errors
Our memory can be affected by what others remember- susceptible to misleading information
Social influence and CONFORMITY
Sherif
Identify when a spot of light started moving by pressing a button and estimate how far the light has travelled
-when watched a bunch of confederates guessing long and short distances
>ptps tended to provide estimates of movement which matched closely that of the confederate they watched
estimates were long lasting
INFORMATIONAL INFLUENCE- private change
Social influence and CONFORMITY
Asch
Normative influence on line task
-Change answers to fit in with rest of the group
>public change but not private
Social influence and
Memory conformity
Loftus (1974)
Ptps witness an event and then at retrieval receive incorrect suggestions
>Misinformation is provided in the form of written instructions from the experimenter so there is an indirect social component
Roediger et al. (2001)
*Social transmission of false memories *
>Confederates recall a false memory not in the witnessed scenes
>Strong effects of social influence
low and high probability items:
-greater conformity for high probability items
Social influence and Memory errors
Memory improvements:
Allan and Gabbert (2008) found little evidence to suggest long-term social influence effects for accurate memories
Allan & Gabbert, 2008
house hold scene presented to ptps
- confederate made judgements either confidently or not
- effect larger and long lasting for false info but not true memories
Discrepancy detection hypothesis
False memories tend to stand out- when there is a discrepancy in the semantics of something, our attention is focused more-so on this
Social factors that effect magnitude of social influence on memory
> Effect greater for face to face or (perceived) face to face interactions
Small effects linked to the confidence displayed by confederate at immediate testing
Memory conformity more likely to be due to informational influence
Social influence results in long lasting and private change
Normative influence effects cannot be excluded but more likely to occur at face-to-face and public testing
Strong social element. We tend to follow certain people more than others
People we consider more likely to have got the correct answer
People to whom we feel socially closer (minimal group effect)
Social influence effects on memory:
Possible mechanisms
> Social influence errors are source memory errors
Item information recalled but source is lost (misattribution)
False memory is greater if similar to the schema of the episode (gist memory)
Efforts to reduce source memory errors reduce conformity
Drawing attention to the source of information
Distinctiveness of false memory (dissimilar to episode)
Weldon & Bellinger (1997)
Collaborative inhibition (CI)
Remembering in groups-
collaborative memory vs individual score
Nominal group score= individuals totals added up (only counting repeated items once)
Nominal group recall>Collaborative recall>Individual memory
WHY?
>Motivational factors:diminished personal accountability, dispensability of effort etc.
BUT… even when motivational factors diminished by introducing monetary incentives still CI
More likely :Production blocking- more to do with recalling in a group being difficult- interference or forgetting
Memory errors-
An adaptive mechanism
We have adapted to retain information that is most likely to be needed in the environment in which it operates (Schacter, 1999),
Memory errors occur when adaptive memory mechanisms fail to identify which info is essential
What do you need to know
Diff types of memory errors: Forgetting due to encoding Directed and Motivated forgetting False memories Bias (+ material from Research Focus lecture) Social influence on memory Collaborative inhibition
Meissner & Brighams (2001)
Meta analysis: Other race face recognition bias
>People are more likely to correctly recognise a face of their own race
>Shorter exposures and longer retention intervals increase the own race bias (own>other) suggesting link between weak encoding and face bias.
>ORBs an be found across racial groups for members of own group
>Amount of interracial contact is a significant but weak predictor of the ORB
Developmental evidence of ORB
Kelly et al (2007)
Study based on the fact that infants show habituation to studied faces.
>faces have become familiar and therefore there is
»>No bias at 3 months but it appears fully developed by 9 months.
Developmental evidence of ORB
Sangrigoli et al. (2005)
Adopted Korean adults (between the ages of 3-9 years) raised by white families in Europe showed a memory bias for Caucasian and not Asian faces.
>system responsible is plastic– so theories of the effect should include mechanisms to account for this
Face processing:
Role of attention
Zou et al. (2015)
One group studied own and other race faces under full attention conditions. A second group had their attention divided between face processing and another task (tone detection).
»results showed that under full attention there was a clear own race bias (own>other). With divided attention the bias disappeared (own=other).
Expertise based theories
Racial segregation > developing greater expertise in processing and remembering own race better than other races
Developmental studies (Kelly et al 2007) show how babies initially dont have bias until they have more contact with own race (more time spent with caregivers).
-BUT the effect can be reversed by spending more time in presence of other races (Sangrigoli et al. 2005)
Configural processing theory
Relationships between permanent facial features (e.g. eyes, nose, mouth) and enables the processing of the face as a whole rather than a collection of individual features
-Inversion disturbs the relationship between features (upside down faces)
Representation models
The face space model
Valentine (1991)
Regards to memory representations-
So faces are initially processed configurally
-Assumes that each facial feature and inter feature relationships are normally distributed in a population and represented as dimensions of the face’s memory representation.
