Dr. hernandez is researching the effect of a new treatment for depression. she is so excited about this treatment because she is sure it will people. when she hands out the placebo pills, she is able to keep a neutral expression on her face. when she hands out the actual pills, she can't but let a little smile curl her lips and she bounces up and down very slightly due to her expectations the pill will really these people. she is not aware she is doing anything different. as her student, you need to point this out to her to save the study from bias.