I've noticed that several psychological studies purport to measure one thing, but once participants enroll, they end up measuring something completely different.
For example, I recently came across a study where participants were told that the study was meant to help create personalized nutrition and exercise programs. The participants were then given fake DNA test results and what was actually measured was their response to the placebo effect of the test results.
What are the ethics of this? Don't such studies make it less likely that people will enroll in such studies in future and degrade the scientific endeavor in general? Is there no way for psychology to make progress without lying to unwitting study-participants.