Nonpolitical Images Evoke Neural Predictors of Political Ideology

Abstract

SummaryPolitical ideologies summarize dimensions of life that define how a person organizes their public and private behavior, including their attitudes associated with sex, family, education, and personal autonomy [1, 2]. Despite the abstract nature of such sensibilities, fundamental features of political ideology have been found to be deeply connected to basic biological mechanisms [3–7] that may serve to defend against environmental challenges like contamination and physical threat [8–12]. These results invite the provocative claim that neural responses to nonpolitical stimuli (like contaminated food or physical threats) should be highly predictive of abstract political opinions (like attitudes toward gun control and abortion) [13]. We applied a machine-learning method to fMRI data to test the hypotheses that brain responses to emotionally evocative images predict individual scores on a standard political ideology assay. Disgusting images, especially those related to animal-reminder disgust (e.g., mutilated body), generate neural responses that are highly predictive of political orientation even though these neural predictors do not agree with participants’ conscious rating of the stimuli. Images from other affective categories do not support such predictions. Remarkably, brain responses to a single disgusting stimulus were sufficient to make accurate predictions about an individual subject’s political ideology. These results provide strong support for the idea that fundamental neural processing differences that emerge under the challenge of emotionally evocative stimuli may serve to structure political beliefs in ways formerly unappreciated.

Predicting the knowledge–recklessness distinction in the human brain

“…Although typical fMRI analyses are descriptive in nature and lack predictive power, new methods are emerging that try to find multiregional brain activity patterns that collectively predict a specific cognitive condition or individual characteristic (14)(15)(16)(17)(18)(19)(20). This is a particularly challenging task, given that, with fMRI data, the number of predicting variables is generally much higher than the number of observations, and hence there is a risk of producing either computationally intractable or strongly overfit models (15,21,22).…”

“…A new method has been suggested that tries to tackle this problem by using elastic-net (EN) regression. EN regression uses a mix of L1 and L2 regularization to prevent overfitting, while at the same time ensuring that the final model includes all of the relevant brain regions (14,15,21). This new method could potentially be applied to predict the MPC's "culpable" mental states based on a person's fMRI data.…”

What in the World Is Moral Disgust?

“…At stake is a normative and practical issue-of whether a typical human reaction justifies us in drawing moral conclusions, something that, whether we like it or not, we all have a tendency to do. In particular, disgust plays a prominent role in the thinking of political and moral conservatives [Graham et al 2009;Ahn 2014]. Lord Devlin [1968] famously wrote that deeply felt and widespread disgust is a reliable indicator of the limits of what can be tolerated in any society in order to preserve basic social conventions.…”

Association between the dopamine D4 receptor gene exon III variable number of tandem repeats and political attitudes in female Han Chinese

“…Starting with a study of Madsen [6] showing a role of serotonin in dominance behaviour, biology has increasingly become a focus of explanation in understanding ideas related to political and other social attitudes. Among dispositional factors related to broad biological processes that have captured recent attention are neural structures [7][8][9][10] and cognitive processes [11] including physiological response to threats [12], facial expression processing [13] and sensitivity to disgust.…”