Final answer:
Biofeedback instruments mirror an individual's physiological responses and allow them to learn control over normally involuntary processes, which is instrumental in managing various health conditions.
Step-by-step explanation:
Instruments that mirror the results of a person's own efforts, enabling them to learn which techniques do or do not control a particular physiological response, are known as biofeedback instruments. Biofeedback is a technique that utilizes electronic devices to measure a person's neuromuscular and autonomic activity, providing feedback through visual or auditory signals. This feedback enables individuals to learn how to exert voluntary control over typically involuntary physiological processes, which can be beneficial in managing conditions such as tension headaches, high blood pressure, asthma, and phobias.