psychology studies for memory

JACOBS

tested the capacity of the STM (how much it can hold)

asked participants (p's) to recall a list of words, starting with 3 words.

after each correct recall Jacobs addeed a word to the list each time until recall was incorrect.

in order to control time he used a 1/2 second menodrome

in order to measure capacity Jacobs took the average score of the p's recall

Findings:

STM capacity ranges from 5-9 items

memory improves with age

digits recalled better than letters

Peterson & Peterson

used 24 students

p's presented with trigrams of consenants e.g. QVX and a 3 digit number

had to count backwards in 3's from the 3 digit number until told to stop (distractor task)

p's then had to recall their trigram after 3,6,9,12 and 18 seconds

Findings:

no body could recall the trigram successfully after 18 seconds

Conclusion:

duration of the STM is 18seconds

BADDLEY

two conditions:

i) p's given list of words that were acoustically simular

ii) p's given list of words that were acoustically disimular

Findings:

i) simular - 55%

ii) disimular - 75%

Conclusion

STM encodes info acoustically

BAHRIK

used p's who had graduated from a USA high school

392 p's, the oldest graduated 50 years ago

2 conditions:

i) recognition group - p's given a list of names to match with the photos from a year book

ii) recall group - p's just had to remember the names of their former peers from the photo

Findings:

i) recognition - 90% accurate when graduated 14 years ago, 60% accurate when graduated 47 years ago.

ii)recall - 60% accurate when graduated 7years ago, >20% accurate when graduated 47 years ago

Conclusions:

duration of LTM is unlimmited, but does need some prompting

BADDLEY

2 conditions:

i) p's given list of words semantically simular

ii) p's given list of words semantically disimular

p's had to wait 20minutes before recalling the list (to ensure it went into the LTM memory)

Findings:

i) simular - 55% accurate

ii) disimular - 88% accurate

Conclusions:

LTM encodes info semantically

LOFTUS AND PALMER 1

showed p's 7 videos, ranging from 4-30 seconds long

then all p's had to fill in a questionnaire

5 different questionnaires, all had the same filler questions but there was one critical question:

'how fast were the cars going when they _____ into eachother'

the 5 different questionnaires had 5 different verbs to fill the gap:

smashed, hit, bumped, collided and contacted

findings:

smashed: average speed estimate 40.8mph

contacted: averaged speed estimate 31.8mph

LOFTUS AND PALMER 2

150 students shown a video of a multi-car crash

then asked 1 of 3 possibilities:

i) how fast were the cars going when they hit each other?

ii) how fast were the cars going when they smashed into eachother?

iii) control group - weren't asked about speed

1 week later p's were asked: 'did you see any broken glass?' - there was no broken glass

Findings:

i) hit - 7 p's reported seeing broken glass

ii) smashed - 16 p's reported seeing broken glass

iii) control - 6 p's reported seeing broken glass

DENT:

children give fewer details and are unlikely to correct missunderstood information

supported by ROBBERT AND LAMB:

reviewed 161 abuse interviews

findings:

68 of those contained missunderstood info or the interviwer misinterpretated the child

2/3 of these interviews remained uncorrected

DENT is also supported by FIN ET AL

interviewed witnesses (kids and adults) to a staged bank robbery

after a day both ages were equally accurate in their recall

after 5 months, the children struggled to remember any detail

FIN ET AL suggested childrens interviews should be video-taped as often court hearings can take 5 months

CECI AND BRUCK concluded there a 3 things which effect a childs recall:

i) repated Q's - if the interviewer repeats Q's the child will assume they have given an incorrect answer and change theirs

ii) sterotypes - if a child hears something negative about the accused, they are more likely to report that infomation in the interview

iii) encouragement - phrases such a 'think really hard' or 'its really important' may encourage a child to make up detail in order to impress the interviewer

elderly

COHEN AND FALKNER

young adults (av.35yrs) and eldery adults (av.70yrs) shown silent tape of a kidnapping

then given 2 summaries to read after 10minutes

1 contained accurate info the other contained inaccurate info

p's then had to recall the video

findings:

the elderly were more likely to include the inaccurate detail in their recall

COXON AND VALENTINE

p's shown video of staged crime

3 age groups, children (7-9yrs) young adults (16-18yrs) and elderly (60-85yrs)

Findings:

the children and eldely were less accurate in recall than then young adults

BUT the elderly were no less suseptible to misleading q's then young adults, only children were effected by them.

DEFFENBACHER

reviewed 21 studies and concluded that anixiety has an effect on EWT in accordance to the Yerkes-Dodson Law, i.e as anixiety increases so does performance up to a optimum point, after this point performance decreases.

supported by LOFTUS study

2 conditions;

1) p's overheard low key discussion about faulty computers, person emerged with greasy hands and a pen

2) p's overheard hostile and heated argument, crashing chairs and smashing glass, person emerged with bloody hands and a paperknife.

P's asked to pick the person who emgered from 50 photos

1) low anxiety - 49% accurate. 2) high anxiety - 33% accuarte

founded by Giselman

after a study, he found that a cognitive interview produced 41.4 correct facts compared to standard interview only producing 29.4 correct statements

the cognitive interview consists of 4 stages:

1) contextual reconstruction - witnesses have to report pshycial surrounds and emotional feelings

2) they are econuraged to report every detail, no matter how minute

3) the order of the events changed - i.e. witness may be asked to recall the events in a reverse order - incase any detailed is missed - different way of thinking

4) change perspectives - witnesses asked to recall events from someonelses perspective (view)

BEKHARIAH AND BENNETT

reviewd 27 studies, found that the cognitive interview was more accuarte in every case.

but after interviewing the police force, concluded it had limmited use due to the 4th instruction (changing perspective)

KEBBEL AND WAGSTAFF

held interviews with members of the police force and found that they thought the congnitive interview was very time consuming and is now only used in serious crimes

GISELMAN:

found the interview to be uneffective on kids under the age of 6years. Now, the interview can only be used on children aged 8+ years.