Loftus and Palmer Evaluation

Loftus and Palmer Evaluation

Lab Experiment Method

Loftus and Palmer's research conducted a lab experiment which is high in control. This means that the study is easy to replicate. All pp were presented with the same seven videos of car crashes in experiment 1 and the wording of the critical question was the same except for the verb. This makes the study more reliable/ consistent.  We are better able to imply cause and effect between the IV (verbs) and DV (speed estimate) because no other extraneous variables interfere with these. However, laboratory experiments tend to be low in ecological validity.  This means the study did not closely match the memory recall of a real eye witness to a crime, therefore making it hard to generalise findings to real life.  In a real accident you may be more shocked/ anxious and therefore not remember as much making your speed estimate less accurate.  In addition, in a laboratory setting you may be expecting to have to recall something, so concentrate more on the video improving your speed estimate.  The procedure used despite being scientific and supporting psychology as a science brings into question how much the research tells us about how eye-witnesses would react in real life.  

Ecological Validity

Loftus and Palmer’s research was low in ecological validity, due to the artificial environment that the study was conducted in.  All pps had to watch the same 7 film clips of traffic incidents and were questioned about it using a questionnaire.  This is not what would happen in real life as the witnesses would be there at the accident.  In the study the pps may have paid more attention to the videos as they knew what was going to happen, which means that recall may be less accurate in real life, rather than in an artificial setting.  This, therefore, means that the findings cannot be applied or generalised because memory distorted by leading questions can not be applied to memory recall in real life, due to other variables such as trauma.  However, it can be argued that the research has some similarities to eyewitness testimony.  For example, witnesses would have had to watch the accident and asked by the police what happened, normally in an interview, like in the research where the pps described what happened in the videos before the critical question was asked. Therefore, the research cannot be solely used to draw conclusions about the effects of leading questions on memory. 

Independent Measures Design

Loftus and Palmer used an independent measures design, where each participant experienced only 1 of the 5 verb conditions of the independent variable. This reduces order effects, such as practice, as participants are less able to practice estimating speeds. This therefore increases internal validity as speed estimates are clearly a reflection of the verb used in the critical question, rather than any other variables. However, the design creates a problem of individual differences, such as driving ability, eyesight and memory ability. This means the researcher is less…