Biofeedback is a term that first arose in the 1960s for a methodology that uses instrumentation to record the physiological responses of organisms and then in real time give information about those physiological responses back to the organism. It is presumed that by getting such timely feedback about physiological responding, the organism will learn, through a trial and error basis, how to control the desired physiological response.
The most concise definition of biofeedback is probably that of Olton and Noonberg (1), who characterized it as, ''any technique that increases the ability of a person to control voluntarily physiological activities by providing information about those activities'' (p. 4). In practice, the process of clinical biofeedback training involves the use of a machine (usually a computer-based system in contemporary applications), which allows a therapist to monitor the patient's bodily responses (most commonly surface muscle tension or surface skin temperature). Information concerning the patient's physiological responses are then relayed back to the patient, generally either through an auditory modality (a tone that goes higher or lower depending on, say, electrical activity of the target muscles increasing or decreasing) and/or a visual modality (now usually a computer screen where, e.g., surface skin temperature is sampled and then graphed on a second by second basis in real time). Through this physiological feedback, it is anticipated that the patient will learn how to control his/ her bodily responses through mental means.
Biofeedback arose as an application of the learning theories of B.F. Skinner, Hull, Thorndike, Dollard and Miller, and John Watson. In particular, Neal Miller postulated that the established principles of learning that had so far been applied to overt behaviors could validly be applied to behaviors that were covert and presumed not under voluntary control.
Classical conditioning is also referred to as Pavlovian Conditioning after the seminal work of Russian scientists Pavlov and Sechenov in the early twentieth century. Classical conditioning is a laboratory learning paradigm by which a neutral stimulus (conditioned stimulus; CS) comes to elicit a new response (conditioned response; CR) by repeated pairing in close temporal proximity with another stimulus (unconditioned stimulus; UCS) that already elicits that response (unconditioned response; UCR). In subsequent presentations of the CS, the organism will then emit the UCR without pairing of the UCS. For example, the UCS might be food and the UCR is salivation, the CS, the ringing of a bell, is presented immediately prior in temporal pairing with the UCS, food. After repeated pairing of the ringing bell with food, the organism will come to salivate in response to the bell's ringing. The behaviors conditioned in this paradigm are typically unlearned, such as most physiological responses utilized in biofeedback practice. However, the learning paradigm most often appealed to as the theoretical underpinning of the field of biofeedback is not classical conditioning. Rather, biofeedback is generally considered a form of operant conditioning. This learning theory postulates that the consequence of a response changes the likelihood that the organism will produce that response again. The essential assumption of operant conditioning is that behavior is lawful and follows the rules of cause and effect and probability.
A basic supposition of operant conditioning is, if you wish a behavior to continue, you reinforce or reward that behavior. If you wish a behavior to decrease, or to stop completely, you do not reinforce that behavior. Thus, within the theoretical framework of operant conditioning, the main way that you strengthen a behavior is to follow it in close temporal proximity with a reward. The definition of a reinforcer is any stimulus change that occurs after a response and tends to increase the likelihood that a response will be repeated. It is important that the reinforcer follow the desired behavior quickly such that the delay in the presentation of the reward is kept to an optimally short delay. As the delay in the reward increases, the effectiveness of the reinforcer is generally decreased. There are many examples of positive reinforcement in our everyday life-receiving a bonus for outstanding work, receiving an A in a course for intensive studying, scoring a touchdown in a football game and the crowd's adulation.
In addition to positive reinforcement, there are three other possible consequences to behavior in operant conditioning: (a) Negative reinforcement involves the removal of a consequence to a response that results in reduced likelihood that the behavior will be repeated in the future. (b) Positive punishment involves adding a consequence when a response is performed that serves to decrease the likelihood of the response occurring in the future. Examples are plentiful: child misbehaves, parent scolds child, child less likely to misbehave; drive over the speed limit, get ticket, less likely to speed; do poorly at work, get demoted, less likely to perform poorly on the job. Negative punishment involves the removal of a consequence to a behavior that serves to reduce the likelihood of that behavior occurring in the future. An examples is a parent playing with their child who is clearly enjoying the playtime; the child starts to yell loudly, the parent stops playing with the child, parent less likely to engage in positive play with the child. In clinical biofeedback applications, these other types of reinforcement contingencies are rarely used, with biofeedback clinicians preferring to use positive rewards to influence behavior.