Forgetting: When Memory Lapses
A. How Quickly We Forget:
Ebbinghaus's Forgetting Curve
studies of forgetting were done by Hermann
syllables (consonant-vowel-consonant, e.g., XOR, LIM,
Measures of Forgetting
- Retention: Proportion of
material which is retained or remembered
- Recall: Reproduce information
without any cues
- Recognition: Select
previously learned information from an array of
- Relearning: How long does it
take to relearn what you had previously learned?
C. Why We Forget
1. Ineffective Coding
Decay = memory traces fade with age. Not
true except with dementia.
Interference Problem = forgetting
information because of competition from other material
Interference: New learning interferes with
old learning (NIO)
Interference: Old learning interferes with
new learning (OIN)
4. Retrieval Failure
5. "Motivated" Forgetting
The Repressed Memory
Freud (1901): Described a process he called "repression"
Individuals began reporting to their
therapists the recollection of memories, long buried
from the past, which claimed experiences of sexual
abuse, traumas, and even the witnessing of murder. These
memories were considered to be "repressed" as Freud
Loftus: research showing some false memories can
in experimental studies is 30% of subjects will
develop a false memory and 23% accepted that they had
an experience even though they didn't remember it.
memory report can look like a genuine memory to
observers, even if the person does not explicitly
report remembering the events
patients show too many memories
is more widespread than we used to think.
memories" are forms of "believed-in imaginings," that
is, even if not factually true, the person reporting
them believes them to be true
and others (e.g., police) need to be very careful not
to suggest that there are buried memories
The Physiology of Memory I: Patient
(Henry Gustav Molaison, 1926-2008)
Here's his story
in a YouTube video [5'25"] from an animated TedEd
working memory was fine. He could remember things for 5
to 10 minutes.
- He could not
remember any experience longer than about 5 to 10
minutes, that is, anything that would be a new addition
to his long-term memory. For example, he saw the same
doctors and psychologist day after day, but never
learned who they were.
- He also had
very significant memory loss of events in his life from
before his operation.
- His overall
intelligence remained intact and he could generally care
for himself, carry on conversations, and enjoy himself
with puzzles and other games.