Is there any evidence?
Sleep Learning?
~Simon & Emmons (1956)->96 general information questions were chosen according to criteria:
=>The information was not generally known.
=>The answers required were not outside the verbal experience of the participants.
=>The questions could be answered in short phases/single words.
->Eg. In what kind of store did Ulysses S Grant work before the war? Before the war, he worked in a hardware store.
->The questions and answers were recorded and played while the participant was asleep. Participants' EEGs were recorded throughout the night to monitor their sleep.
->Participants were asked the questions they heard overnight. Performance is above chance, learning has occurred.
->Scores divided by EEG sleep state:
=>Awake but relaxed=80%; Drowsy=50%; Light sleep transition=5%; Asleep=no effect.
->The performances on the questions was better than chance in the morning, dependent on their EEG state at the time the answer was played, and good in they were awake when the answer was played.
~Bruce, Evans, Fenwick &Spencer (1970)
->Participants first had to learn pairings of nonsense syllables. Nonsense syllables were used to reduce the possible effect of differential experience with real words.
->Three conditions:
=>Facilitation-presented with more nonsense syllables which they would be tested on later in a post-test while they slept.
=>Interference-presented with the same syllables but scrambled.
=>Control-presented with music
->Performance on the post-test should be better in the facilitation group, worse in the interference group and no difference in the control group.
->Presented the material to the sleeping subjects then awakened them immediately. No evidence for sleep learning was shown.
Learning while Unconscious?
=>The absence of learning about external events while asleep does not imply that we can't remember internal events such as dreams (Pace-Shott et al., 2003).=>It also does not imply that sleep itself might not play an important role in the consolidation of memories.
=>Memory during Anaesthesia (Levinson 1965):
--10 dental surgery patients experienced mock crisis during surgery.
--The patients were put into deep Anaesthesia, at this point the anaesthetist announced with alarm that the patient's lips are too blue. The surgery resumed when the anaesthetist was satisfied. One month later the patients were hypnotised.
--4 patients produced almost verbatim report of the anaesthetist's comments. 4 produced partial reports and only 2 produced no recall at all under hypnotises.
--Serious ethical questions, tiny sample size & unreplicated, suggestibility under hypnosis, no measure of degree of anaesthesia....
--But is it possible? Yes, it raised at least two issues: that (1) anaesthesia maybe not be total-cocktail issue and the hypnotic procedure could be sleep inducing, and (2) different tests of memory may reveal different evidence for memory from anaesthesia.
Explicit vs. Implicit Memory:
->Explicit memory involves conscious recollection of prior experiences while implicit memory is revealed on tasks that do not require reference to a specific episode (Graf &Schacter, 1985)
--Task to access EM:
- Free Recall-Subjects attempts to remember target information without any assistance from the experimenter.
- Cued Recall-Subjects attempts to remember the target information in the presence of some specific cue (such as an associate of the word).
- Recognition-Subject is resented with a stimulus and must decide whether it is one that he/she was asked to remember.
--Task to access IM:
- Word stem completion-few letters starting the word presented.
- Word fragment completion-letters provided in not continuos form.
- Degraded picture naming-incomplete photos shown.
->Jacoby(1991):Process Dissociation Procedure
=>A task to estimate conscious Recollection(R) & Automatic memory(A)
=>Induction Test-Produce items from any source; Exclusion Test-Only produce items that you didn't study previously.
=>When expressed in probabilities, Inclusion=R+A(1-R), Exclusion=A(1-R), R=Inclusion-Exclusion and A=Exclusion/(1-R)
We only remember what we attend to.
=>Memory for common objects is often surprisingly poor:
1.Nickerson & Adams (1979) investigated hot accurately people remember a common object, a US penny. People were asked to:
- Draw a penny from unaided recall
- Draw a penny given a list of its visual features
- Choose from among a list of possible features those which do appear on a penny
- Indicate what was wrong with an erroneous drawing of a penny
- Select the correct representation a penny from among a set of incorrect drawings.
2. Richardson (1993) described British examples with the coin task. Also, Martin & Jones (1995) or Morton (1967).
3. Rinck (1999)provides a related German finding with keypads.
- People were given papers with empty columns representing the keypads.
- They were asked to fill in the layout of the ten digits 0 to 9 on phones and calculators.
4. Loftus, Loftus & Messo (1987) studied about weapon focus, which refers to the concentration of some witness's attention on a weapon during a crime, leaving less attention available for viewing other items. The idea that arousal during a crime causes attention focusing such that only central information (such as the attacker's knife rather than face) is attended to.
- They examined this phenomenon by presenting witness with slides depicting an event in a fast-food restaurant. Half on the subjects saw a customer point a gun/cheque at the cashier.
- In experiment 1, participants made more eye fixations on the weapon than on the cheque, and fixations on the gun were longer than on the cheque.
- In experiment 2, when asked to identify the person from a line-up, the memory of the subjects in the weapon condition was poorer than those who were in the cheque condition.
5. Christianson & Loftus (1991) put people into 3 conditions:
- Emotional-a woman injured near a bicycle), Neutral-a woman riding a bicycle and Unusual-a woman carrying a bicycle on her shoulder.
- subjects watched either one sequence of slides containing a critical slide in the middle. In experiment 1 and 2, only a single eye-fixation was allowed on the critical slide by presenting to at 180ms(1) or 150ms(2). Despite constraint, memory for a central detail was better for the emotional condition.
- In experiment 3, subjects were allowed 2.7 secs to view the critical slide while the eye movements monitored. Memory for detail information of the emotional slides were better.
- Enhanced memory for detail information of an emotional event does not occur solely because more attention is devoted to the emotional information.
- Subjects in the unusual condition performed poorly when recalling both the central and the peripheral detail; those in the emotional condition performed well for the central detail.
- Changes in eye movements in stressful situations are relatively easy to demonstrate but memory changes can be more subtle.
=>People are quite adept at discriminating between complex pictures they have seen a short time before and those that have not.
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