Here's a description of a study that used a factorial design to study whether those skinny sculptures (pictured) might inhibit people from unhealthy eating. The study is described by Pacific Standard journalist Tom Jacobs here. The study's authors hypothesized that being exposed to Giacometti's long, lean forms would motivate people to eat less. In this study, the researchers used potato chips as an unhealthy food that people might want to restrict eating. Here are some details about the study's design.
The study featured 128 members of a “sensory consumer panel.” Participants had previously taken part in taste-testing sessions, and presumably believed this was a similar exercise. Each sat in a small cubicle containing a computer. For about half the participants, the screen saver featured “three thin figures from Giacometti’s sculpture Piazza.” For the rest, the screen was blank.
They were first instructed to memorize either a two-digit or a 10-digit number. Afterwards, they were served 20 Pringles Original potato chips, and asked to indicate how much they enjoyed the snack. They were told they could eat as many of the chips as they desired.
a) Based on your reading of the design (above), what are the independent and dependent variables (IVs and DVs)? (Hint: This is a factorial design).
b) For each IV, is it independent groups or within groups? What are each IV's levels?
c) How would you state the design? (Hint: Your answer should have an "X" in it!)
Now for the results:
“The participants who had been exposed to the Giacometti screen saver consumed less than the participants who had been exposed to the neutral white screen saver,” the researchers report.
The sculptures had this effect ....whether they were keeping in their head the simple two-digit number, or the difficult 10-digit one. That latter finding is particularly significant, given that, in the real world, people often have many things on their mind as they sit down to eat. The results suggest the visual cue of the skinny sculptures does its job even under such conditions.
d) Draw a sketch of the results that the journalist has described above. Remember to put the DV on the y-axis. A line graph or a bar graph would both be OK.
e) Looking at the sketch you drew, do you think there is an interaction in the data? What about main effects?
After you draw your own graph, you can inspect the actual results of the study here, under Figure 1. The authors report that in their graph, there is a main effect for screen saver condition, but the interaction is not significant. Notice how the journalist describes the lack of an interaction by using the term, "whether or not," as in "the sculptures had this effect whether they were keeping in their head the simple two-digit number, or the difficult 10-digit one."
