week 10 false memory Flashcards
what do normal people think about memory error
Simons and Chabris (2011): surveyed the general public
-2/3 of people think that memory works like a “video camera”
* Probably the single greatest consensus among memory researchers…
* This is simply not true
* Memory errors can accumulate over time
memory error cause
-We are more likely to confuse things that were studied nearby in time. Drewnowski & Murdock (1980) found that most intrusion errors come from the immediately preceding list – with intrusions from distant lists being much less likely.
-Learned content that is similar leads to greater memory errors
Underwood and study on similar content on memory error
Underwood (1965) found higher levels of false alarms (erroneously saying ‘yes’ to novel items) if the novel items were associates of studied items. For example, if ‘dog’ was a studied word, then there are higher false alarm rates to words such as ‘canine’ or ‘cat’. There were lower false alarm rates for words such as ‘couch’ or ‘groom’
o Underwood argued that these results were due to implicit associative responses – when you learn a word, you might think of other related words.
o For example, when studying ‘boy’, you might think of the word ‘girl’. ‘Girl’ then gets associated to the current situation, which makes you more likely to false alarm to it when presented with it later. Even events that we imagine or are reminded of can be a source of false memories.
The Deese-Roediger-McDermott (DRM) paradigm (Roediger & McDermott, 1995)
- Participants study a list of words that are all associates of a given word
- “robber”, “crook”, “burglar” are all associates of the non-presented word thief
- “door”, “glass”, and “pane” are all associates of the word non-presented word window
- At test, participants had high rates of falsely remembering the non-presented words
- This applied to both recall and recognition
- Recognition of the critical lure was often recognize with very high confidence despite the fact
that participants are very good at rejecting unrelated words
The Deese-Roediger-McDermott (DRM) paradigm (Roediger & McDermott, 1995) on perceptual error
Sommers and Lewis (1999): DRM lists where participants study phonologically similar words
* Studied “fat”, “that”, ”cab” – all similar to the non-presented word cat (critical lure)
* Studied “buff”, “put”, “bet” - all similar to the non-presented word but (critical lure)
* Findings resemble those from semantic false memory
* Very high levels of false recall and recognition of the criticial non-presented words!
What happens if you warn participants about false memories before DRM task?
Gallo, Roberts, and Seamon (1997): inclusion of a forewarning condition
* Participants were told that the lists were specifically designed to induce false memories and given examples of the effect
* False memories were reduced but not eliminated
What moderates the effects of false memory?
Note: DRM lists often contain a large number of associates of the critical word
* What happens if you study less of them?
* Robinson and Roediger (1997): manipulated the number of associates on study lists
* False recognition increases rapidly as the number of studied associates is increased
* In other words: the more similar content we learn, the easier it is to falsely remember something that is similar to what we experienced
Why do false memories in the DRM paradigm occur
- Generation of the critical lure during learning. implicit associative idea: when you see words like
‘sheets’, ‘dream’, ‘slumber’ you might be reminded of the word ‘sleep’. This makes it more likely that you will falsely recall or recognize the word later. This is referred to as a source monitoring error – false memory occurs because we are unable to distinguish between a real event (a presented word on a list) and an imagined one (generating the word ourselves in our own minds) - other possibility of false memory occurs because we use the “gist” of a learning episode in conjunction with real memories to reconstruct the event. Fuzzy trace theory (Brainerd & Reyna, 2002)
-the critical lure gets activated via a process of spreading activation
-A number of computational models have been developed where retrieval is determined by the similarity to all memories (Global similarity accounts)
experiment to prove the Generation of the critical lure during study
- Overt rehearsal procedure: have participants rehearse the words out loud as they’re studying the words
- Subjects often rehearse words to preserve their memory for the material
- If the critical lure is generated during study, it should appear in their rehearsals
- As it turns out, participants do rehearse the critical lure during study!
- …but false memory is still present even when they don’t rehearse the critical words (Marsh & Bower, 2004; Seamon et al., 2002)
Fuzzy trace theory (Brainerd & Reyna, 2002)
- “Verbatim” traces – real memories that are incomplete or have encoding errors
- “Gist” traces – an overall sense of what was learned in an event or study list
Why doesn’t forewarning reduce false memory
Fuzzy trace theory: Gist is still a useful or necessary cue to reconstruct an event
-spreading activation:Activation spreads through the network involuntarily
-Global Similarity:False memory is an involuntary consequence of the similarity between the memories and the cues – forewarning won’t change this!
Why does increasing the number of associates increase false
memory
-Fuzzy trace theory: Stronger extraction of gist traces due to more associate
-spreading activation: Each associate activates the critical lure, so studying more associates increases the activation of the critical lure even more
-Global Similarity: More similar items in memory = greater global similarity, and greater levels of false memory!
Why do false memories still occur even if they are not generated at study
-Fuzzy trace theory: Gist is used at retrieval
-spreading activation :Activation may not be high enough for the words to be rehearsed at study, but high enough at retrieval to generate false memory
-Global Similarity: Rehearsal is completely unnecessary for false memories – it falls directly from the similarity between the items
Candidate theory: the critical lure gets activated via a process of spreading activation
basis of activation monitoring theory
* Words we learn become activated – this makes it easier to retrieve them later
* Words associated with what we learn are also activated
* This activation of associated memories leads to false memory at retrieval
Global similarity accounts
number of computational models developed where retrieval is determined by the similarity to all memories (essentially a parallel search). For recognition memory, similarity is calculated to each item in memory. These similarity values are summed together to produce an index of global similarity – indicating how similar a probe item is to the entire contents of memory. If this value is sufficiently high, then the probe word is endorsed.
According to global similarity accounts:
o Forewarning doesn’t reduce false memory as false memory is an involuntary consequence of the similarity between the memories and the cues.
o Increasing the number of associates on the list increases false memory as the more similar items you have in your memory, the greater the global similarity and therefore the greater the levels of false memory.
o False memories still occur even if they are not generated at study, as rehearsal is completely unnecessary for false memories - it falls directly from the similarity between the items
Reconstructive memory study : Barlett (war of the ghost)
-Barlett make participant (war of the ghost) recall the story across longer intervals. As the time between reading the story and recall of the story increased, errors increased. While there were omissions of details, there were also intrusions of other details. Participants were more likely to intrude with details from their own cultural life stories. As such, Bartlett described memory as a reconstructive process, not just like a recording we can view. Memory is reconstructed every time we remember
How do we reconstruct our memory
- Memory isn’t like a recording we can view
- Instead, memory is actively reconstructed every time we remember
- Similar in spirit to fuzzy trace theory
Reconstructive memory study Kintsch et al. (1990)
found different rates of forgetting for content in memory from sentences. Memory for the underlying meaning of the sentence was unaffected by the delay interval (immediate to four days), but memory for surface form and text(e.g. What the words were in the sentences, passive versus active voice) declines rapidly. This means that even as we forget the specific words or phrases, we can still use our memory for the meaning to reconstruct a sentence or story
Memory is subject to misinformation –the misinformation effect
- “What you get out of memory depends on the question you ask”
- What happens if you ask a misleading question? (Loftus & Palmer, 1974)
- Subjects saw a video of a car stop at a stop sign, then drive ahead and hit a car
- Two groups:
- Control group asked: “How fast was the car going when it hit the other car?”
- Experimental group asked: “How fast was the car going when it smashed the other car?”
- Experimental group gave higher speed estimates, also were more likely to claim they saw something they didn’t (broken glass)
How does the timing or context of misinformation impact memory?
- Lindsay (1990): Subjects watched slides of a maintenance person stealing a computer and some money, two days later tested on memory
- Difficult condition: Same narrator immediately gives misinformation
- Easy condition: Different narrator gives misinformation two days later
- Less misinformation in reports in the easy condition
- Misinformation presented long after the event is easier to disregard, or possibly not part of the memory
False childhood memories lost in a mall
- Loftus and Pickerell (1995): “Lost in the mall” study
- Participants were asked about a number of actual childhood memories
- Told to describe a story in which subjects were “lost in a shopping mall”
- Many participants described a story in detail even though it may never have occurred
False childhood memories!
* Wade et al. (2002): Hot air balloon study
- Researchers solicited photos from the participants’ families and stories about what the participants did as children
- Received confirmation that the participants had never been in a hot air balloon
- Subjects presented with photos, along with a photoshopped picture of the participant as a child in a hot air balloon
- For each picture they were told to remember the event, and if they couldn’t remember it, to picture the event
- Most subjects did not initially remember the event, but after repeated interviews, as many as 50% of participants described the event
Implications of the misinformation effect
- Wells and Bradfield (1998): when witnesses pick a suspect from a lineup, post-identification feedback from police can influence their confidence
- Positive feedback example: “Good – you picked the right person”
- Witness’s confidence increases significantly relative to no feedback
Are memory immune to error?
- “Flashbulb” memories (Brown & Kulik, 1977)
- Possible exception to erroneous normal memories
- Highly confident and vivid recollections of major life events, such as:
- Assassination of John F Kennedy
- The Challenger explosion
- The September 11 attacks on the World Trace Center
- People often report that they remember where they were, who they were with, and are highly confident
- Brown and Kulik argued that these memories are preserved due to the high level of emotional content
