Loftus & Palmer

Cognitive area

What is the background theory of Loftus & Palmer’s study?

schema theory

What is a schema?

Schemas - a mental representation of everything an individual understands. You can have schemas for objects and events, and they are usually based on your past experiences. (e.g. bank robber: stick figure, male, black and white striped hat, with eye mask, etc.)

How can schemas impact memory?

• Schema theory proposes that memory is influenced by what an individual already knows, and that their use of past experience to deal with a new experience is a fundamental feature of the way the human mind works.

• Memory involves interpreting what is seen or heard, recording bits of it, and then reconstructing these bits into memories when required.

• So, memory can be distorted or biased by certain features of the situation. R

• esearch has shown that we are more likely to remember details of an event that are consistent with our preconceived schemas.

• This suggests that eyewitness testimony is highly unreliable bc it can be influenced by such things as subtle differences in the wording of questions.

How can reconstructive memory produce negative outcomes?

• false accusations

• wrongly go to jail

• cause stress-related health problems

• false/bizarre memories

fill in the gaps. “Loftus & Palmer’s study focuses on the effects of “——-” on an individuals abillity to accurately remember events

leading questions

what are leading questions?

questions that are phrased in a way of suggesting the expected answer

what was the expectation of Loftus & Palmer’s study?

The expectation was that any information subtly introduced after the event through leading questions would distort the original memory.

(Look at handout to see diagram on how memory can be explained using the computer analogy)

what was the aim of experiment 1?

To investigate how information provided to a witness after an event will influence their memory of that event

what sampling method was used in experiment 1

opportunity sampling

Outline the sample in experiment 1

45 students from the university of Washington were divided into 5 groups with 9 ps in each group

Why is the sample from experiment 1 ungeneralisable to certain people?

• sample is ungeneralisable as not everyone goes to Washington uni, so it is unrepresentative of the target population. Most university students are also a similar age, so it may be ungeneralisable to people out of the typical uni age bracket.

what experimental method was used in experiment 1?

lab exp

what measure/design was used in exp 1?

independent measures design

what was the independent variable of exp 1?

wording (verb) of the critical question, hidden in a questionnaire:

• “About how fast were the cars going when they hit / smashed / collided / contacted / bumped each other?"

• So there were 5 conditions of the IV

what was the dependent variable of exp 1?

estimated speed (mph) given by the ps

outline the procedure of exp 1

• All ps were shown the same 7 film clips of different traffic accidents which were originally made as part of a driver safety film

• After each clip, ps were given a questionnaire which asked them firstly to describe the accident and then answer a series of questions about the accident

• There was one critical question in the questionnaire, "About how fast were the cars going when they [IV] each other?"

what were the results of experiment 1?

what conclusions were drawn from the results of experiment one?

Loftus & Palmer suggest 2 explanations for the results of exp 1:

1. Response bias: the different speed estimates occurred bc the critical word (e.g. “smashed” or “hit”) influences or biases a person's response

2. Memory is altered: the critical word changes a person’s memory so they actually “see” the accident differently (i.e. more / less severely)

what was the aim of exp 2?

To investigate whether leading questions will alter memory of an event: leading to the recollection of something which is not true

which sampling method was used for exp 2?

opportunity sampling

outline the sample of exp 2

50 students from University of Washington were divided into 3 groups with 50 ps in each group

what method was used for exp 2?

lab exp

which measure/design was used for exp 2?

independent measures design

what was the independent variable of exp 2?

wording on a question on speed in a questionnaire:

• critical question with the verb “hit”

• critical q with the verb "smashed”

• control group: no question about vehicular speed

what was the dv of exp 2?

answer to critical question, “Did you see broken glass? Yes or No”

outline the procedure of exp 2

• all ps were shown a one-minute film which contained a 4-second multiple car crash

• they were then given a questionnaire which asked them to describe the accident and answer a set of questions about it

• there was a critical question about speed:

      - one group: “About how fast were the cars going when they smashed into each other?”

      - another group was asked: “About how fast were the cars going when they hit into each other?”

      - control group did not have a question about vehicular speed

• one week later, all ps, without seeing the film again, completed another questionnaire about the accident which contained the further critical question, “Did you see any broken glass - Yes or No?”. There had been no broken glass in the original film.

what were the results of exp 2?

the no. of ps who reported seeing broken glass in each condition of the IV:

Response     Smashed       Hit      Control

Yes                    16              7            6

No                      34             43         44

what conclusions were drawn from the results of exp 2?

• Memory is reconstructive: the results are not due to a response bias. This is bc the critical question, “Did you see any broken glass?”, was asked to all ps a week after the event, suggesting the leading question about speed had actually altered the participants’ long-term memory

• L&P proposed that 2 kinds of information go into out memory for a “complex occurrence” such as this;

       1. The information obtained during the perception of the original event from our senses 

       2. The post-event info that is gained after the fact from leading questions, speaking to others, media

• info from the sources integrates over time so we can’t determine where the info came from

evaluate the research method & techniques used

• controlled lab conditions - extraneous variables are controlled, so high internal val. (e.g. irl speed estimates may be impacted by where  a person is standing, but lab exp ensures each ps witnesses accident from same position)

• watching films is not the same as watching a real accident, so ps lack emotional involvement 

• the study involved a task that people are not good at - estimating the speed of a moving vehicle

evaluate the reliability of the study

• quantitative data is relatively straightforward to assess the reliability of the measurements that are made (ps could be asked to repeat task and it would be expected for them to get the same speed estimates each time)

• standardised procedure for exp 1 bc everyone watched the same 7 clips so they answered the q for the same crash (control variable) - increases internal reliability & external reliability (as the exp can be repeated to get similar results (test-retest)

evaluate the validity of the study

• lacks ecological validity as it was a controlled lab exp, meaning results are less representative of real life

evaluate the sampling bias of the study

• opportunity sample of US students were easy to obtain

• students have unique characteristics (e.g. maybe more intelligent, with better memories than the avg person) so might be less likely to be affected by leading q’s - this research may underestimate the effect of leading q’s

evaluate the type of data collected

• quantitative data - estimates of speed and number of YES / NO answers - this produces simple conclusions, but is fairly superficial

evaluate the ethics of the study

• deception was relatively mild (no psychological harm) & helped collect important data about the inaccuracy of eyewitness testimony 

• fully informed consent not obtained from ps - if ps were aware of the aims, they would have been aware that the questions were “leading” and been more careful in the responses they gave

evaluate the ethnocentrism of the study

• America is an individualist culture which may affect the willingness of people to be influenced by leading q’s. - ppl from collectivist cultures may be more influenced by what other say as they value links within a group over individual needs