Memory Errors and Forgetting

Distortions and Intrusions  Although having several retrieval cues can help us recall more information, they can also serve to confuse us.  Consider the following example from Owens, Bower and Black (1979)…

Nancy arrived at the cocktail party. She looked around the room to see who was there. She went to talk with her professor. She felt she had to talk to him but was a little nervous about just what to say. A group of people started to play charades. Nancy went over and had some refreshments. The hors d’oevres were good but she was interested in talking to the rest of the people at the party. After a while, she decided she’d had enough and left the party. Some subjects also heard that passage, but w/ this prologue: Nancy woke up feeling sick and she wondered if she really were pregnant. How could she tell the professor she had been seeing? And the money was another problem. The prologue offered some background information and some retrieval cues, which increased recall (not unlike the “laundry” we discussed earlier). However, the background info. also lead to more INTRUSIONS (memory for information not present), such as “The professor got Nancy pregnant.”

Distortions and Intrusions cont.  Bartlett (1932) was the first to demonstrate distortions for prose. –Read stories about Native Americans. gist –Subjects were good at recalling gist information. –Omission of detail was systematic. Tended to omit information that did not make sense to his subjects.

Intrusions and Distortions cont.  Brewer and Treyens (1981) –Subjects sat in an office for a few minutes. –Later asked what objects were in the office. –Results showed that subjects remembered “typical” items. 1/3 remembered books that were NOT there. 1/3 remembered a bulletin board.

So what?  Are subjects actually remembering information that was never presented?  YES! If we ask Ss to rate their memories on confidence, or if we time their responses, we find that “real” memories do not differ from “inferred” memories.  If Ss have equal confidence in accurate and inaccurate memories, what does that tell us about confidence in memory? Should we give more weight to testimony that in which a witness is very confident in their memory?

Intrusions and Distortions Applied  Elizabeth Loftus has done several studies demonstrating how memory fallibility has real-world consequences.  Leading questions: –“Hit” vs. “Smashed” study. –Stop sign vs. Yield sign study.

Sources of Memory Errors  Obviously, our memory system is pretty efficient, but the cost of that efficiency is in accuracy. What are some factors that lead to inaccurate memories?  Schemas  Schemas: prototypical memories for events and situations. –When recalling info, we may recall from our schema, not from what actually happened.

Sources cont.  Reconstruction  Reconstruction: when you recall information, you are actively reconstructing the information… you may fill in “gaps” with the most probable information (perhaps from schemas).  Intention  Intention: if we want to remember details, we can get ourselves to do so. However, the “default” setting for memory seems to be memory for gist.

Sources cont.  Time  Time: the simple passage of time affects memory adversely… why? –Decay: with the passage of time, memory trace fade or erode. –Interference: you cannot access one memory because others are getting in the way. Retroactive: new events interfere w/ old. Proactive: old events interfere w/ new.

Jenkins and Dallenbach (1924) Two groups of subjects learned CVC trigrams, and tested under a variety of retention intervals. The groups differed in that one group spent the retention interval awake and the other group spent that time sleeping. Here are the data: Retention Accuracy Retention Interval (Hours) awake asleep Do these data support decay or interference theory?

Paired Associates Test To test retroactive interference: 1 st List2 nd ListTest List A-BA-CA-B (experimental) A-BC-DA-B (control) If RI is at work, what should we see in the data? To test proactive interference: 1 st List2 nd ListTest List A-BA-CA-C (experimental) B-DA-CA-C (control) If PI is at work, what should we see in the data?

Hypnosis  Will memory be enhanced if the person is placed under hypnosis?  NO!!!! –Ss will recall more, but they have more intrusions. –They are compliant, and as such are very susceptible to leading questions. –State-dependent memory problems.

False Memories / Memory Illusions  Roediger & McDermott (1995) –Present Ss w/ list of associated words, missing one “target” word (e.g., tired, bed, night, dream, etc., but not SLEEP). –With immediate recall, Ss tend to recall the non- presented target item. –More importantly, when asked whether they “remember” or “know” the word was on the list, they report an actual memory for the item.

False Memory cont.  Garry, Manning, Loftus & Sherman (1996) –Ss complete Life Events Inventory (LEI). –Ss lead through imagination exercises. –Ss fill out LEI again. The results show that when Ss imagine events that they previously said did not happen to them, they are more likely to say they DID happen to them.

Emotion and Memory  There is a strong relationship (.90) between the emotionality of an event, and it’s vividness in memory. This does NOT mean that the memory is accurate however.  Emotional events seem to be less resistant to forgetting over time… –Perhaps they are perceived better. –Perhaps Ss think about them more.  How can these findings be reckoned w/ a notion of Freudian repression?

Flashbulb Memory  Memories that have extraordinary clarity, highly emotional, and are retained despite the passage of many years. The JFK assassination is an example for one generation… most of “us” may have the Shuttle Explosion as a Flashbulb Memory  Neisser and Harsch (1992) –Tested immediate memory for Shuttle Explosion, and then tested it again 3 years later. –There was little agreement w/ the two “memories” despite the alleged clarity and confidence of the Ss.

Long, Long-term Remembering  We do not remember much from the first 3 or 4 years of our life, a phenomenon called childhood amnesia.  Why does this occur? Freud: repression. Cognitive: schemas are not yet developed. Physiological: the brain changes a lot in the first few years… the memories may have been stored in a “format” that the adult brain cannot interpret.