A study investigating the effects of torso compression (achieved by wearing shapewear) showed (in an experimental game) that it reduced risky decisions. At the same time, participants who underwent torso compression became more sensitive to sensations coming from their stomach and more aware of signals coming from their heart. The paper is biological psychology.
Good decisions depend not only on what is happening around us, but also on how accurately we are aware of what is happening within our bodies. The ability to detect and interpret internal signals such as heartbeat, hunger, fullness, nausea, and fatigue is known as interoception. These body signals can influence your emotions, behavior, and decision-making by alerting you to risks, stress, and changes in your physical needs.
People who are more accurately aware of their internal states are less impulsive and more likely to make favorable choices, but most of the evidence to date comes from studies that do not allow causal inferences. Researchers are therefore increasingly interested in whether intentionally altering bodily sensations can directly alter decision-making. One possible method is to apply pressure to the body. This is because the pressure from tight clothing can strengthen signals from your stomach and heart, focusing your attention on your body.
Stefania Polzin, a researcher at the German Institute of Human Nutrition and other institutions, and colleagues investigated the effects of torso compression on people’s cardiac interoceptive accuracy, cardiac interoceptive awareness, and gastric interoceptive sensitivity.
In other words, they investigated whether wearing clothing that compresses the torso (in this case shapewear) affected participants’ accuracy in interpreting signals coming from their hearts, their recognition of those signals, and their sensitivity to signals coming from their abdomens.
We also wanted to see if this affected risk-taking behavior. The study authors hypothesized that wearing shapewear may increase the perception of signals from the heart and stomach, leading to less risk-taking. Their hope was also that this experimentally induced improvement in sensitivity to signals from the stomach and heart would be associated with reduced risk-taking.
The study participants were 44 people between the ages of 18 and 45. They were required to be physically and mentally healthy, of normal weight, not taking regular medications, and without a prior diagnosis of mental or physical illness. They were also required to be fluent in German. The average age of the participants was 26 years, and 28 of them were women.
Participants were invited to the laboratory in the morning (10:00 a.m.) for two consecutive days and were asked to fast from 9:00 p.m. the day before the visit. In the laboratory, subjects were asked to wear provided clothing. One day I was in shapewear (which compressed my torso) and the other day I was in loose clothing. Shapewear is a form-fitting garment designed to compress and smooth parts of the body, creating a slimmer or more defined look under other clothing.
Participants completed tasks measuring risk judgment and interoception (cardiac interoceptive accuracy, cardiac interoceptive awareness, and gastric interoceptive sensitivity) while wearing the clothing. Cardiac interoceptive accuracy is the ability to perceive cardiac activity, especially heartbeats. Participants completed a heartbeat discrimination task. In this task, participants listened to an auditory signal and reported whether the signal was synchronized with their heartbeat.
Cardiac interoceptive awareness was assessed as the level of agreement between the actual accuracy of participants’ answers in the previous task and their self-reported confidence that the given answer was correct.
Here, we defined gastric interoceptive sensitivity as the ability to perceive satiety and fullness signals from the stomach. To assess this, participants completed a water stress test. In this test, participants were first instructed to drink water until they were full, and then until their stomach was completely filled with water. The study authors divided the amount of water participants drank to get full by the amount of water they drank to get full, which they called their satiety percentage. Lower satiety was interpreted as better gastric interoceptive capacity.
Risk-taking was measured using the Columbia Card Task. This task has 32 cards. Most of them will earn participant points, but a few will be loss cards. Participants choose the number of cards they would like to turn over in each trial. Trials vary in the number of losing cards and the number of points earned for each winning card or lost for each losing card. The number of cards selected on each trial was the individual’s absolute risk score.
The results showed that participants were less likely to take risks while wearing shapewear. There was also an increase in gastric interoceptive sensitivity and cardiac interoceptive awareness. Cardiac interoceptive accuracy remained unchanged.
“Increased gastric interoceptive sensitivity with compression predicted decreased risk behavior. Post hoc, we observed that this was primarily driven by women, as women showed increased interoception and decreased risk-taking, whereas men showed decreased interoception,” the study authors explained. “These findings demonstrate how physical manipulation changes interoception, which causally leads to changes in behavior.”
However, the researchers note that these particular results should be interpreted with caution, as the sample was not gender balanced and was not originally intended to investigate gender differences.
This study contributes to the scientific understanding of the psychological effects of body compression. However, it should be noted that this study was conducted with a relatively small number of individuals, and the risk-taking decisions may not have real consequences for the participants. The results of studies with larger samples, where risky decisions have real consequences for participants, may differ.
The paper, “Trunk compression enhances interoception and leads to changes in risk preference,” was authored by Stefania Polzin, Anoushiravan Zahedi, and Soyeon Q. Park.
