PSY2004 Research Methods & Ethics in Psychology
Assessment One: Quantitative Lab Report
A researcher at a north London institution was interested how effective the polygraph is at detecting lies. Moreover, they wanted to know whether the surroundings during testing influenced any results.
Each participant was connected to psychophysiological equipment measuring heart rate (HR), electro dermal activity (EDA), and respiratory rate (RR). For this analysis, only EDA will be included as a representative measure of the autonomic nervous system activity where higher positive value represents higher levels of EDA, taken as a measure of more arousal. In other words, the higher the EDA value, the more your palms sweat.
Each participant completed the same set of tasks. They were asked a series of ten questions and they either answered truthfully or they lied. They were instructed to give an untruthful answer on 3-5 of the ten questions (whether they told the truth or not was verified once the testing session was over). Participants also engaged in a control condition where they were presented with coloured pieces of paper. They simply looked at the paper which was presented for ten seconds in front of them. The average EDA activity was then calculated for each participant when they lied, told the truth, and were shown coloured paper (LIE, TRUTH, CONTROL)
The study consisted of two different groups, with 40 participants in each group.
One group performed the polygraph testing session as part of their Biological and Cognitive Psychology laboratory class. In the lab class of approximately 30 students, they were divided into six groups of 3-6 students. In each group, one student volunteered to be the participant and the other students were responsible for testing, asking question, presenting coloured pieces of paper and data recording (GROUP SESSION)
Participants in the second group were invited to take part in an experiment in return for course credits (the nature of the experiment was unknown to the participant). The testing session was conducted by two professional looking polygraph administrators and each participant was tested on their own in a small room. The participant was told only at debriefing that the two polygraph testers were not actually trained professionals but instead two members of staff from another department (INDIVIDUAL SESSION)
All data, from both the lab class and the individual testing sessions, was analysed by one person (the researcher of the study).