Pain: Cognitive and Contextual Influences

Recent pain research has been greatly influenced by the gate control model of pain presented in 1967 by psychologist Ronald Melzack and neuro-scientist Patrick Wall. They suggested that both physiological and clinical data, as well as everyday experience, run counter to the classical view that pain simply arises from overstimulation of the somatosensory system. Anatomical, physiological, and psychological evidence point to a complex interaction of both peripheral and central information in responding to noxious stimuli.

Melzack and Wall also noted that the amount of pain after an injury is greatly influenced by contextual factors. An athlete, soldier, or worker may suffer a severe wound yet not report pain until long after the event, likely because the individual's attention was focused upon some vital task when the injury occurred.

The gate control theory, emphasizing parallel ascending and descending effects within the nervous system, suggested that pain is not a single sensation. Rather, it has several distinct dimensions that Melzack and Kenneth Casey called (1) the sensory-discriminative system, (2) the motivational-affective system, and (3) the cognitive-evaluative system. Put simply, the first deals with identifying the location and intensity of the pain (how it feels), the second with our emotional response to that sensation (how it makes us feel), and the third with [Page 717]our interpretation and response to that event (how we think about it and act).

Consequently, pain research and management must deal with sensory, emotional, and cognitive mechanisms. This is reflected in pain measurement techniques, in functional imaging studies, in medical interventions, and in psychological approaches to pain reduction. This entry discusses some of the techniques used to measure pain, behavioral measures that illustrate how pain is influenced by cognition, and how pain is influenced by context effects.