Video Module 16: Forgetting Flashcards
What are the 3 hypotheses of why we forget information? Which ones are correct?
- memory decay hypothesis
- interference theory
- retrieval failure
- Evidence suggests that all three are aspects of forgetting information
memory decay hypothesis
items not recalled or studied for a period of time will lose their strength as a result of automatic decay
- suggests that memory nodes and links fall apart over time if they are not accessed
- memory trace is lost from LTM over time
interference theory
other events and memories interfere with our ability to recall items
- suggests that items in our memory do not decay
- new memories make older memories difficult to locate, especially if they are closely related or competing for activation
retrieval failure
the inability to remember something is a temporary result of insufficient activation of nodes or links
- suggests that nodes or links in our memory do not decay
- nodes that would activate are below activation threshold
forgetting curve
displays the rate at which we can retain information over time
- generally shows that we tend forget a lot very quickly, but over longer periods of time we forget less
- generally looks like slow exponential decay
proactive interference
When the info you’re trying to recall in the present makes it more difficult to recall related but different info in the future.
- When old information interferes with learning new information
- E.g. Learning first that red means stop and green means go, then later having trouble learning that green means stop and red means go.
retroactive interference
When info you’re trying to recall in the present makes it harder to recall related but different information you learned in the past.
- When new info interferes with old memories
- E.g. Trying to remember how to speak Portuguese, but becoming confused due to trying to learn Spanish in the present.
retrograde amnesia
when a patient cannot remember events that occurred before a brain injury
anterograde amnesia
when a patient cannot remember events that follow a brain injury; when they can no longer form long term memories following a brain injury
- anterograde amnesia patients can still recall things that happened before the disruption
What are the pros of retroactive and proactive interference?
- retroactive interference is beneficial because it helps us adapt to new environments; it is helpful that we can override old habits when trying to adjust to new ones
- proactive interference is beneficial because it helps us recall fundamental info; sometimes the first thing we learn is the most important
temporally-graded retrograde amnesia
the pattern of memory recall for patients with anterograde amnesia in which they have trouble remembering what occurred before the accident
Who is patient HM? What did he tell us about memory loss?
Patient HM underwent a procedure in which parts of his medial-temporal structures—his hippocampus—were removed. This caused him to have anterograde amnesia, in which he had an inability to form new long term explicit memories. However, researchers found that he was still able to form new long term implicit memories (procedural, motor).
- HM provided an example of how damage to the hippocampus affects a person’s ability to form new explicit memories, but not new implicit memories.
- Anterograde amnesia does not usually affect implicit memory before or after brain injury
What is the double dissociation between the amygdala and hippocampus with regard to memory?
- Damage to the amygdala = deficit in implicit memory, but explicit memory remains intact
- Damage to the hippocampus = deficit in explicit memory, but implicit memory remains intact
A study in which patients were exposed to a blue light before hearing a startling noise found that patients with damage to the amygdala had memory of the blue light, but no fear response when shown the light again (no implicit memory of the relationship btwn the light and the sound). Patients with damage to the hippocampus had no memory of the blue light or noise, but had a fear response after seeing it (implicit memory of the relationship, no explicit memory). - The hippocampus is involved in explicit memory, while the amygdala is involved in implicit memory
What is the difference between remembering and knowing?
Knowing is being familiar with information but not knowing specific details. Remembering is being familiar with information and being able to recall specific details of the source memory.
- knowing = feeling that you studied sth, but not knowing the source of that feeling
- remembering = feeling that you studied sth and recalling the specific details of what you studied
What is the pattern of cortical activation involved in being familiar with info vs. having recollection of a source memory?
Greater activation in the rhinal cortex is linked to greater familiarity with information. In other words, if the rhinal cortex is active during encoding, a participant is more likely to be familiar with a stimulus later on.
Greater activation in the hippocampus is linked to greater likelihood of remembering a source memory. In other words, if the hippocampus is active during encoding, then later a participant is likely to have recollection of a stimulus.
