Sperling 1960 - Sensory register capacity
Presented a 3x4 grid of letters for less than a second, 50 milliseconds and asked ppts to immediately recall the letters of one row. Average of 4 letters - although when using partial report technique, showed that iconic memory capacity is 10 items but they fade too quickly to report them all.
Conrad 1964 - STM encoding
Visually presented students with letters one at a time. Found that letter which are acoustically similar are harder to recall from STM than those which are acoustically dissimilar.
Conc - STM mainly encodes acoustically even when presented visually.
Miller 1956 - STM capacity
Visually presented students with letters one at a time, found that capacity of STM is the magic number of 7 plus or minus 2.
However, also found that ‘chunking’ increases the capacity of STM. Combining and organizing letters into meaningful chunks which line up with information previously stored in LTM.
Peterson and Peterson 1959 - STM duration
Presented ppts with groups of 3 letters (trigrams) and asked to recall after an interval. During the interval, ppts asked to count down from a random number to prevent them from rehearsing the trigrams. Found that the longer the interval, the worse the recall.
After 3 seconds, 80% correct recall
After 18 seconds, less than 10% correct recall.
Conc - duration of memories in STM = 30 seconds or less.
Baddeley 1966 - LTM encoding
Ppts given 4 sets of words: acoustically similar/dissimilar and semantically similar/dissimilar.
Asked to recall the words either straight away or following a 20 minute task.
Found that recall was much worse for semantically similar words than for semantically dissimilar words. Recall from LTM was the same for acoustically similar/dissimilar words.
Conc - LTM predominantly encodes information semantically
Bahrick et al. 1975 - LTM duration
Tested US graduates on their very long term memory showing them classmate photos years after graduation. After 34 years, 90% correct recall for names and faces, but recall declined after 48 years.
However, as memory and its duration declines significantly with age, this could be the reason for the forgetting, not the duration of LTM.
Dual Task method - Baddeley 1974
If the capacity of stm is the magic number 7 plus or minus two then you wouldnt expect to be able to complete 2 stm tasks at the same time such as remembering a 6 digit number and completely true or false questions. Found that most people could do both, meaning that stm must have more than one component and replaces the idea of a unitary stm
- reasons for the development of the wmm
Finke et al. 2012 - procedural LTM
Case study of PM, professional cellist whose episodic and semantic memory had been affected. Couldn’t remember specific musical facts but could read and play music.
Loftus and Palmer 1974 - car accident experiment
Showed ppts a film simulation of a car crash and asked them how fast they thought the cars were going when they…. smashed/hit each other (used different verbs). In the case of using a more aggressive verb, ppts estimated a faster speed.
Aim: to test if language can affect an eye witness testimony.
Experiment 2 - a week later ppts were brought back and asked if there was any broken glass on the scene,. Those who had been asked the question with the more aggressive verb and therefore had estimated a faster speed said that there was glass. There was no glass.
47% in smashed condition said yes, compared to 17% in the hit condition.
Weapon Focus Study - Loftus 1979
When asked to identify the man from 50 photos, ppts in condition 1 (pen and grease) were 49% accurate, compared to condition 2 (knife and blood) who were 33% accurate.
Christianson and Hubinette - year?
1993.
Questioned real life witnesses to genuine bank robberies. Found that the victims (in more danger and therefore more anxious) recalled more information - still evident 15 months later.
Conc - better recall in stressful events.
High e.v but could have been proximity.
Yuille and Cutshall 1986
Questioned 13 witness to a real life shooting who all gave extremely accurate accounts several months later. However it was those closest to the scene and therefore in more danger and more anxious who provided the most detail.
Conc - most distressed=most accurate.
Fisher et al. 2012
Studied genuine police officer interviews from Fl, USA. They found the questions were brief, direct and closed., the sequencing of questions often did not match the witnesses own view of what happened, and the officers often interrupted the witnesses not allowing them to expand on answers.
Concluded that these factors led to ineffective interviews and therefore, Geiselman and fisher created the cognitive interview in 1992.
Kohnken et al. 1999
Found 34% increase in correct information between standard and cognitive interview.
But also found that CI gave more inaccurate information.
Memon et al. year?
1994.
Found that where detectives had had less than 4 hours training in the CI there was no improvement compared to SI.
Geiselman et al. year?
1985.
Showed ppts video of a crime, interviewed them using cognitive, standard and hypnosis. CI elicits more information.
Baddeley year?
1975.
Got divers to learn words underwater and on dry land. Where words had been learnt underwater they were best recalled underwater.
Postman 1960
Aim: To investigate how retroactive interference affects learning.
Procedure: lab experiment. 2 groups. both had to remember a list of paired words. experimental group had to remember another list where the second paired word was different. Control group just had to learn one list.
Findings: Control group recall was more accurate than experimental group recall
Conclusion: Suggests that learning items in the second list had interfered with the previously learnt items on the first list
RETROACTIVE INTERFERENCE
Tulving and Pearlstone - year?
1966.
Gave ppts a written list of 48 words to learn. Split into 12 groups of 4 words each and a one word heading, eg “fruit”.
One group given the headings to help remember the words - cued recall condition. Second group not given the headings - free recall condition.
First group remembered more of the words than the second group.
