Pain Intensity Ratings are Altered by Prior Exposure to an Unrelated Numeric Anchor

Numeric anchoring occurs when exposure to a numeric quantity biases a persons subsequent judgment involving other quantities. This study aimed to determine whether exposure to a random numeric anchor influences how a hypothetical patients pain is perceived. 385 participants read a vignette describing a patient with chronic pain before being randomly assigned to one of four groups. Participants in Groups 1 and 2 spun an online wheel (0-10) designed to land on a high number (8) or a low number (2), respectively. Group 3 spun a similar wheel (A-K) designed to land on a C or I. Group 4 did not spin a wheel. Participants then rated the patients pain intensity using a 0-10 numeric rating scale. This study found that numeric anchoring did influence the perception of a patients pain; however, the anchoring effect was seen only in those who believed they had been influenced by the anchor.