Posture and Pain Research shows that people adopting a dominant pose have reduced levels of stress and feel more powerful than those adopting a submissive pose. Furthermore, it is known that if people feel more control over a situation, they have a higher tolerance for pain. Putting these ideas together, a recent study74 describes three experiments investigating how posture might influence the perception of pain.

(a) In the first experiment, 89 participants were told that they were in a study to examine the health benefits of doing yoga poses at work. All participants had their pain threshold measured both before and after holding a yoga pose for 20 seconds. The pain threshold was measured by inflating a blood pressure cuff until participants said stop: The threshold was measured in mmHg and the difference in before and after thresholds was recorded. Participants were randomly divided into two groups: One group (n = 45) was randomly assigned to strike a dominant pose (moving limbs away from the body) while the other group (n = 44) was assigned to strike a submissive pose (curling the torso inward). The mean change in pain threshold for the group striking a dominant pose was 14.3 with a standard deviation of 39.8, while the mean change in pain threshold for the group striking a submissive pose was −6.1 with a standard deviation of 40.4. Does the experiment provide evidence that a dominant pose increases one’s mean tolerance of pain more than a submissive pose?

(b) Prior research has shown that a person will assume a pose complementary to the pose of a peer or colleague: assuming a more submissive pose if the peer has a dominant pose and vice versa. In the second experiment, 30 participants were told they were participating in a study on relaxation methods and randomly divided into two groups of size 15. Each participant took turns describing nature photographs with a peer who was part of the study and was secretly told to strike either a dominant or submissive posture during the interactions. Pain thresholds were measured in the same way as in the first experiment. Mean difference in pain threshold was −13.8 with a standard deviation of 27.1 for the group with a dominant peer and 4.2 with a standard deviation of 22.9 for the group with a submissive peer. Does the experiment provide evidence that mean pain tolerance is higher if one’s interaction partner is submissive? The data do not have any significant outliers.

(c) As part of the experiment described in part (b), participants were also given a handgrip strength test both before and after the interaction with the peer, and the difference in handgrip strength was measured in newtons. Mean change in handgrip strength for those with a dominant interaction partner is −45.3 newtons with a standard deviation of 46.5 while for those with a submissive partner mean change was −6.8 with a standard deviation of 31.0. The data do not have any very large outliers. Find a 90% confidence interval for the difference in means and interpret the result. Based on the confidence interval, do you believe that there is a significant difference in mean change in handgrip strength between those with a submissive partner and those with a dominant partner?

(d) Since reducing the perception of pain is a goal in health care, what are the implications of these studies for health care professionals?