Memory Errors: Some Initial Examples
In 1992, a plane crashed into an apartment building. Ten months later, researchers
questioned people about the crash, asking them whether they had seen the crash on
TV. More than half of the participants said they‟d seen the crash on the TV special,
even though none had ever been made.
More people were questioned later in they‟d seen the TV special and they were also
asked for details about the crash. Again, they said they‟d seen the special and were
able to confidently give details about the crash. Except most of those details were
Memory Errors: a Hypothesis
Reminder from Chapter 6
Memory is like a giant net with connections linking up nodes of information.
Connections act as retrieval paths, guiding the search through memory
Connections can become a problem however:
As more links are created between one episode and another, the two episodes
are becoming closer and closer
This means that the boundary between the episodes may become blurred and
you may lose track of what info came from where.
This leaves you open to transplant errors: information encountered in one context
is transplanted into another context
Understanding Both Helps and Hurts Memory
Connections are good because they serve as retrieval paths, allowing to locate
information in memory.
Connections are a problem because they make it difficult to see where one episode
ends and some other, related knowledge begins.
This leads to intrusion errors: errors in which other knowledge intrudes into the
The DRM Procedure
Def.: a person sees or hears a list of words that are all related to a single theme;
however, the word that names the theme is not itself included. Nonetheless, people are
very likely to remember (incorrectly) that the theme word was presented.
This procedure works, still yields errors, even if the participants are warned
beforehand. Schematic Knowledge
We can document similar errors with more complex materials, including materials that
you encounter every day. This works because you enter most situations with some
amount of background knowledge.
This knowledge is usually helpful because it helps you as you explore situations
However, can lead to memory errors
Schema: knowledge of how something should usually occur.
Schemata helps with:
Recognizing events and actions as typical in a given situation
Helps recall how an event occurred. They help fill in the gaps in a recollection –
caused either by things you didn‟t notice in the first place or because you forgot
Evidence for Schematic Knowledge
Schematic knowledge can cause errors:
Things you didn‟t notice in a situation are later filled in by your schemata because
you want to regularize a situation, filling in what is supposed to be typical.
The Cost of Memory Errors
Leads to false convictions, due to faulty eyewitness testimonies. Not even that the
eyewitnesses are being malicious, just that they are making memory errors.
Planting False Memories
Participants were shown a clip of two cars in a collision. The participants were then
asked how fast the car was going when it into the car. The participants were
all asked differently, using different terms to describe the collision:
Contacted, hit, bumped, collided, smashed
o When using the term „smashed‟, participants said that the car was going
faster than when the term „contacted‟ was used Later, participants were also asked if they‟d seen glass on the ground, in the video.
Those participants that had been given the term „smashed‟ said that there was glass,
even though there was no glass.
It‟s easier to plant plausible memories than it is for implausible memories (though it is
possible). It is more successful when participants are asked to picture the scenario as it
could have occurred.
Are There Limits on the Misinformation Effect?
Misinformation effect: participants memories are being influenced misinformation they
received after an episode was over.
Using photoshop to modify pictures or just using unaltered pictures to make participants
remember events that never occurred.
Almost 80% of participants were able to „recall‟ an episode, often in detail, that
Children are more susceptible to this than adults.
Avoiding Memory Errors
The confidence we have in our memories is often influenced by factors that have no
effect on memory accuracy.
When these factors are present, confidence will change (up or down) but there
will be no change in accuracy.
The “Remember/Know” Distinction
False memories can feel just as emotional as real memories.
Being able to „remember‟ memories, as opposed to „knowing‟ them, has the effect of
being more accurate.
False memories only have a general sense of familiarity and no recollection of a
This isn‟t always exact but it‟s a good first step to trying to identify a false
Overall, memory errors are mostly undetectable
The Causes of Forgetting Forgetting somebody‟s name right after you meet them isn‟t actually forgetting – it‟s
actually a failure in acquisition. You didn‟t pay attention as the name was said to you so
you never actually learnt it.
“Real cases” of forgetting is when you‟ve actually learnt the information but now no
longer recall it. One of the best predictors of this is time.
Retention interval: the amount of time that elapses between initial learning and
subsequent retrieval; the larger the interval, the more likely you are to forget.
Possible explanations for why time matters:
Decay: with passage of time, memories may fade or erode. May be caused by
death of relevant brain cells. Or caused by lack of use of the connections
between the memories. Without refreshment of these connections, they gradually
Interference theory: new learning interferes with old learning. According to this,
time is correlated with forgetting but does not cause it. Time just creates the
opportunity for new learning to disrupt older leaning.
Retrieval failure: when you learn, you learn with a certain perspective. As time
passes, you lose this perspective. The greater the retention interval, the greater
the likelihood that your perspective has changed, the greater the chance of
Which of these theories are correct? They all actually work on some level.
Retrieval failure does occur. The information is usually recovered later so that means
that interference and decay after not occurred. Retrieval failure is usually complete – no
recollection of any of the target information. Partial failure does occur – tip of the tongue
occurrences. It has been proven that memories do decay with the passage of time.
Interference theory does have some support. However, it has been found that it‟s not so
much the passage of time that determines the interference but the amount of interfering
information between the points.
However, the biggest part of interference is that old info gets woven in with new
info, through connections. This means that there is confusion as