Dr. frolov classically conditioned a dog to flex his right hind leg at the sound of a bell by pairing the ringing of a bell with a mild tug to that leg. in this example, the ringing bell is the:

In an experiment examining the effects tai chi on arthritis pain, callahan (2010) selected a large sample of individuals with doctor-diagnosed arthritis. half of the participants immediately began a tai chi course and the other half (the control group) waited 8 weeks before beginning. at the end of 8 weeks, the individuals who had experienced tai chi had less arthritis pain that those who had not participated in the course.