L&P Aims and Context
- Cognitive approach- this approach looks at how we process information. EWT is where we give an account of an event we have witnessed in terms of a crime usually. It is the processing of this info which is important.
- It is a requirement of the court/law that eyewitnesses affirm that the evidence they give shall be the truth... but is EWT 100% accurate. Highly inaccurate because of distractions(perception, emotions, bias, shock).
- Research has shown that inaccurate EWT is the main factor leading to false convictions in over 75% of cases.(70s)
- one explanation for inaccuracies could be the use of leading questions. This could be police officers, lawyers and solicitors.
- loftus and palmer aim was to investigate the in/accuracy of memory. The first experiment was to see if leading questions bias a persons response.
- Aim- do leading questions affect peoples estimates of such details?
- Experimental method
- 2 experiments- experiment 1- 45 ps shown 7 films of a traffic accident.
- IV=verbs used DV=speed estimates
- asked critical questions of how fast were the cars going when they hit each other?
- split into groups of 9 and hit replaced smashed, collided and bumped and contacted.
- experiment 2- 150 ps saw 4 second clip of multiple car crash.
- split into 3 groups of 50 being asked how fast were they going when they hit/smashed into each other? 1 group given no Qs. All asked 1 week later if they saw any broken glass?
- IV=leading Qs DV=whether they saw glass
L&P Finding and Conclusions
- Experiment 1 - estimates varied from 40.8 mph for verb smashed to 31.8 for contacted.
- Verb smashed indicated more speed.
- A single word in this case can disort a witnessws memory for an event.
- Experiment 2- 16 of smashed group said they saw broken glass compare to 7 of the hit group. (ps/50)
- in this case leading Qs or a single word can distort a persons memory of an event.
- Leading questions can affect a persons memory for the event one week later.
- peoples accuracy for reporting the details of a complex event is easily distorted through the use of leading questions.
+ demonstrates clearly how leading questions can have an effect on memory. shows cause and effect.
+validity high as it measured what it was supposed to in first experiment.
+study is reliable as it has been replicated to find a similar results by loftus et al.
+ gave informed consent and were fully debreifed.
- lacks ecological validity as not realistic. In real life...
- experiment 2 low in experimental validity as most Ps didn't respond positively, number for smashed should've been much higher.
- demand characteristics as Ps may have behaved in a way to please the experimenter.
- ethics of stress and discomfort
M +cause and effect
+highly controlled, reliability(repeatable)
-lacks eco validity
R +Loftus et al, Filmore, Marshall
V +study 1
S - too small to be generalised, conducted in a university
E +full informed consent
-stress and discomfort
L&P Context extended
- leading questions may affect peoples ability to judge speeds as Marshall(1969) found when AirForce personnel estimated a car to be travelling at between 10-50 mph when actually travelling at 12mph. This shows we can't accurately estimate speeds.
- Filmore(1971) suggests that words such as smash and hit imply different rates.
- Bartlett who studied the war of the ghosts(1932) and found that we reconstruct our memories inaccurately. Each re-telling of the story became more and more dramatic everytime.