Final answer:
To minimize placebo effects and ensure accurate results, Dr. Schulenberg's study likely utilized a double-blind method where neither researchers nor participants were aware of group assignments.
Step-by-step explanation:
Dr. Schulenberg likely designed his study so that neither he nor his students knew which group they were in to address placebo effects. This approach is part of a double-blind study, which aims to minimize both experimenter bias and the influence of participant expectations on the outcome of the research. The placebo effect is significant because it highlights how people's beliefs can affect their experiences and the experimental results. In this case, by having both parties unaware of the group assignments, any differences in outcomes between the treatment and control groups can be attributed to the treatment itself rather than to expectations or biases.