Fix It A Psychology Student Wanted to Replicate John Watson's Fear-Conditioning Study

Fix It
A psychology student wanted to replicate John Watson's fear-conditioning study for her senior thesis project. After getting permission from her sister, the student introduced a variety of stimuli, including objects and sounds, to her 6-month-old nephew. She found that the baby was not fearful of any stimulus, except for a loud noise she produced by banging pans together. The student recorded that each time she made this loud noise the baby began to cry. She also noted that the baby was particularly fond of a particular stuffed animal. When presented with the stuffed animal the baby would smile and reach for it. The student then began to bang the pans together after the baby was presented with the stuffed animal. Eventually the student noticed that the baby would begin to cry when presented with the stuffed animal, even in the absence of the loud noise. After several weeks of working with her nephew, the student thanked her sister for using her nephew for her project. She wrote up the results and presented them at a regional psychology meeting where to her surprise someone told her she had behaved unethically.
What research design is the student using? Is there a problem because she based her study off of Watson's work? What do you think about the ethics associated with this study? How would you change it?