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A series of three studies on healthy men found that their political opinion changes were weakly associated with changes in testosterone levels. These changes were also somewhat associated with fluctuations in cortisol levels, though this relationship was more complex. The research was published in Adaptive Human Behavior and Physiology.
Testosterone and cortisol are two important hormones produced and used by the body. Testosterone is a steroid hormone primarily produced in the testes in men and the ovaries in women. It plays a key role in developing male characteristics, muscle mass, and libido. Testosterone also influences psychological traits such as aggression, confidence, and competitiveness. Elevated testosterone can support risk-taking and assertiveness, but excessive levels may impair emotional regulation.
Cortisol is a steroid hormone produced by the adrenal glands. It is released in response to stress to help regulate metabolism, blood sugar, and the immune system. Cortisol helps the body manage stress, but prolonged elevated levels can lead to negative effects like anxiety, fatigue, and immune suppression. Chronic high cortisol can negatively affect memory, concentration, and mood, contributing to feelings of burnout and depression.
Study author Benjamin G. Serpell and his colleagues noted that levels of these hormones fluctuate throughout the day, as does the strength of opinions a person holds. They wondered whether the strength of opinions might be associated with hormone levels. To explore this, they conducted a series of studies examining the association between opinions on political topics such as the United States–Mexico barrier and the United Kingdom’s decision to leave the European Union (referred to as the “Wall” and “Brexit”).
The first study aimed to describe changes in cortisol, testosterone, and opinions over the course of a day. Following this, the researchers conducted an experiment in which they used physical exercise to alter hormone levels. In the final experiment, they used a psychological stimulus—viewing a sad video—to achieve similar changes.
The participants included 30 healthy men recruited from the general community. Fifteen were younger, with an average age of 24 to 25 years, while the other 15 were older, with an average age of 55 years. All participants reported being physically active and were broadly aware of both the “Brexit” and “Wall” politics. However, none said that these issues particularly affected them personally.
In the first study, participants provided saliva samples at three time points during the day (9:00 AM, 12:00 PM, and 3:00 PM) over three separate days. For the second study, 25 of these men performed a short bout of intense exercise on a cycle ergometer, an activity expected to elevate testosterone levels. Saliva samples were collected five minutes before the exercise and 15 minutes after, and participants rated their political opinions on the two topics at each time point.
In the third study, 20 participants watched a one-minute video of a sad, crying girl accompanied by audible sobbing. This video was expected to lower testosterone levels. Saliva samples were taken before and 15 minutes after viewing the video, and participants rated their opinions as in the earlier studies.
Participants expressed their political opinions by rating their agreement on a scale from 1 (strongly oppose) to 7 (strongly support) in response to two questions: (1) What do you think about Donald Trump’s immigration policy in terms of building a wall on the Mexican border (i.e., Wall)? and (2) Do you support Britain’s decision to leave the European Union (i.e., Brexit)?
The first study showed that both hormone levels and the strength of political opinions fluctuated throughout the day. Both hormone levels and opinions were stronger at 9:00 AM than at 12:00 PM or 3:00 PM. Younger men also had higher testosterone levels than older participants.
The exercise conducted in the second study increased both hormone levels and the strength of opinions, with one exception: cortisol levels in older men at 9:00 AM remained unchanged. In contrast, viewing the sad video in the third study decreased testosterone levels and weakened the two political opinions. In both the exercise and sad-video interventions, cortisol levels increased.
“This work identifies that opinion stability, in men, varies in a manner potentially linked to relatively small physiological fluctuations in testosterone concentration and, to a lesser extent, cortisol. These links also appear to be strongly individual in nature,” the study authors concluded.
The study makes a valuable contribution to the scientific understanding of the links between hormone levels and political opinions. However, it is important to note that the observed associations were relatively weak overall and less clear in the case of cortisol. Additionally, the study design does not allow for definitive causal conclusions about the relationships between hormone levels and political opinions.
The paper, “Fluctuations in Cortisol and Testosterone Map to Fluctuations in Opinion Strength in Healthy Men,” was authored by Benjamin G. Serpell, Blair T. Crewther, Phillip J. Fourie, and Christian J. Cook.
