Dr. Lonsbary is a cognitive psychologist who is curious about how mood affects memory. She recruits 60 high school students. When a participant would come to her laboratory, Dr. Lonsbary would greet the participant and then randomly (based on a computer algorithm) assign them to one of three conditions. The participants were then given an unlabeled CD to listen to; for participants in condition A, the CD contained a 5-minute piece of happy music; for participants in condition B, the CD contained a 5-minute piece of sad music; for participants in condition C, the CD contained 5 minutes of silence.
They were then escorted into a different room, where they were greeted by a research assistant who conducted the experiment. The research assistant sat the participants in front of a computer screen and told them that a list of 25 words would be displayed on the screen. They were instructed to listen to the CD with headphones while trying to memorize the list of words. All participants were given the same list of 25 common words to remember (e.g., desk, gray, plane, car, spoon, etc.).
When 5 minutes had passed, the screen displayed a question asking them whether they felt happy, sad, or neutral. After the participant responded, a new screen was displayed asking them to type in all the words they could remember from the list of 25 words. All participants were given 3 minutes to type the words they remembered. Afterward, the participant was thanked and dismissed.
At the end of the experiment, Dr. Lonsbary compared the mean number of words remembered between the three groups.
In Dr. Lonsbary’s study, which of the following is NOT present?
Group of answer choices
a control variable
a manipulation check
a placebo group
a treatment group
