Edexcel A2 Psychology - Criminal Psychology Lab Experiments

Research Methods –

Lab Experiments:

· Study cause and effect relationships between an independent and dependent variable. The independent variable is researcher manipulated. In experiments into eyewitness testimony, such as Loftus and Palmer’s, the independent variable may be the presence of a leading question in an interview. The dependent variable may be the accuracy of the witness’s statement.

· Lab experiments are based around an experimental hypothesis. This hypothesis may be based upon a theory. The hypothesis is either confirmed or amended depending on the findings of the study. In Loftus and Palmer’s experiment, the hypothesis was that eyewitness testimony would be affected when leading questions were present in interviews.

· The best example of a lab experiment into eyewitness testimony was Loftus and Palmer’s experiment. Participants in different conditions were shown films of car crashes and given questionnaires about the films after each one. The questionnaires were all the same, except for one which varied between conditions. This question was the independent variable. It asked participants ‘How fast was the car going when it hit the other car?’ but the word ‘hit’ was replaced with ‘collided’, ‘smashed’, ‘bumped’ or ‘crashed’ depending on which condition the participants were in. This…