Which of the following is a biofeedback device?

• A. A digital watch
• B. A balance scale
• C. A stethoscope
• D. A bathroom scale

Answer: (D)

Biofeedback involves using real-time information about a physiological process to help a person learn to regulate it. A bathroom scale fits this idea because it gives immediate feedback about body weight, a physiological parameter. That reading can guide behavior—diet, exercise, and hydration choices—creating a loop where you act, see the result, and adjust again. The other devices don’t provide ongoing feedback about your own bodily processes in a way that supports self-regulation: a general digital watch is mainly a timekeeping device, a balance scale measures weight distribution rather than a personal physiological state, and a stethoscope is a clinician tool for listening to internal sounds rather than giving you personal feedback to modify your physiology.