cognitive case studies Flashcards
what was the aim of loftus and palmer experiment 1?
to test the effect of leading questions on recall
what was the aim of loftus and palmer experiment 2 ?
to see if a leading question changes a persons subsequent memory of the event
what was the experimental design of loftus and palmer?
independent measures design with repeated measures
1= snapshot study
2= longitudinal study
what were the ivs of loftus and palmer?
the type of verb used - hit, contacted, smashed, bumped, and collided
what were the dvs of loftus and palmer 1?
estimate of speed
what were the dvs of loftus and palmer 2?
whether the pps said they saw broken glass
what was the sample in loftus and palmer 1?
45 us college students - in 5 groups
what was the sample in loftus and palmer 2?
150 Us college students - 3 groups
what were the materials in loftus and palmer experiment 1 ?
7 brief film clips of car accidents
questionnaire
what were the materials in loftus and palmer 2?
1 min film of a four second multiple car accident
what was the procedure for loftus and palmer 1?
pps asked to describe the accident - answer questions
- included 1 critical question - how fast were the cars going when they (verb) each other ?
- five different verb conditions - hit, contacted, smashed, bumped, collided
. pps were asked to estimate cars speed mph
what was the procedure for loftus and palmer 2?
PART 1- pps were asked to describe the accident - 1 min crash - answered questions - including critical question
. three groups of pps -
g1- the verb smashed
g2- the verb hit
control group - there was no question
PART 2
.pps returned to the lab a week later
. they were asked further questions about the film clips - did you see any glass - there was no broken glass
what were the results for loftus and palmer in experiment 1?
. mean speed was faster for the smashed group - 40.5 mph- than the contacted group - 31.8mph
. pps were bad at estimating speed- actual speeds for the 4 clips - 20,30,30 and 40 mph - pps estimates were between 36 and 40 mph
what were the results for loftus and palmer in experiment 2?
. mean speed estimates were faster for those who heard the verb smashed - 10.46- , than those with the verb hit - 8 mph
. more pps who heard the verb smashed reported seeing broken glass - 16/50 - than the other pps
. 7/50 pps with the verb hit and 6/50 in control group reported seeing broken glass
. most pps correctly reported seeing no broken glass 121/150
what were the conclusions in loftus and palmer 1?
the way a question is asked can influence the answer given
what were the conclusions for loftus and palmer 2?
questions influence the memory that is stored rather than just biasing a persons response,
two types of info make up our memory of a complex event 1- info from our perception of the event and 2 - the info we receive after an event
evaluate the research method and techniques in loftus and palmer?
positive - lab conditions - means extraneous variables can be controlled -
for examples all pps were either shown 7 brief clips from 5 to 30 secs or a one min video
high internal validity
. if it was in real life - speed estimates might be affected where a person is standing - in a lab setting can ensure that each pps witnesses the accident from the same position
. however- watching films is not the same as watching a real life accident - pps lack emotional involvement - might react differently in real life situations.
evaluate the reliability in loftus and palmer
positive - quantitative data is straightforward to assess the reliability of measurements
could ask the same pps to repeat the task a second time and would expect to get the same speed estimates each time
evaluate the sampling bias in loftus and palmer
negative- used students 45 and 150 us college students
they have specific characteristics - some may have only learnt how to drive - some may not know how to drive yet - their speed estimates wont be a good as the general population
however- opportunity sample of us students on degree courses were easy to obtain
evaluate the types of data in loftus and palmer
positive - quantitative data - the estimates of speed and yes or no questions
eg- mean speed for smashed group - 40.5 mph and the contacted group - 31.8 mph and is there broken glass
. this provides simple data - makes it easy to draw conclusions and see if the data is valid
. also uses qualitative data - following each film pps received a questionnaire - asked them to describe the accident
what is visual attention?
the eye records the visual experience - but we dont remember everything
what is change blindness?
failing to notice large changes from one view to the next
what is inattentional blindness ?
failing to notice an unexpected object if attention is diverted
what were the aims in simon and chabris ?
to investigate the factors affecting visual detection rates:
visual similarity of unexpected and attended object
task difficulty
superimposed or live version of a display
nature of the unusual event
what was the design in simon and chabris ?
lab experiment that used independent measures design
how many conditions were there in simon and chabris?
16
how many ivs were in simon and chabris?
4
what were the ivs of simon and chabris?
1- unexpected event was an umbrella woman or gorilla
2- film was transparent or opaque
3- task was easy or hard
4- observed followed black or white team
what is the dv in simon and chabris?
percentage of observers noticing the unexpected event
what was the sample in simon and chabris
self selected sample of 228 mainly American undergraduates
what was the final sample in simon and chabris
192 - 36 ruled out because they already knew about inattentional blindness
what were the materials in simon and chabris
4 video tapes of two teams of three players - black or white- lasts 75 seconds
44-48 secs unexpected event
what was the procedure in simon and chabris
pps took part in only one condition and were tested individually
pps watched black or white team
pps counted silently the number of passes (easy) or number of bounce and aerial passes (hard)
pps wrote down their count scores
pps asked surprise questions about unexpected event - did you notice the anything unusual on the video? did you notice anything other than the six players?
pps who said yes were asked for details
pps who said that they knew anything about inattentional blindness were discarded
pps gave informed consent and were debriefed
what were the results in simon and chabris?
key - 54% pps noticed unexpected event
umbrella was noticed more than the gorilla - 65%
unexpected event was noticed more in opaque condition than transparent - 67%
unexpected event was noticed more in the easy- 64%
what were the conclusions in simon and chabris?
people are less likely to notice unexpected events if they are visually dissimilar to attended events
an unexpected object can be undetected even when it passes through the area of attentional focus - shows no conscious perception without attention.
