Evolutionary and Contemporary Fears Trigger Similar Physical Stress Responses According to New Psychophysiological Study

New research shows modern threats like firearms trigger physiological reactions similar to ancient fears, though evolutionary threats remain more intense.

By: AXL Media

Published: Mar 18, 2026, 2:48 PM EDT

Source: Information for this report was sourced from PLOS

The Adaptive Nature of Human Fear Responses

A study led by Eva Landová at Charles University in the Czech Republic has provided new insights into the physiological mechanisms that prepare the human body to respond to danger. Fear is traditionally viewed as an adaptive emotion designed to minimize harm through a cascade of emotional and cognitive reactions. To understand if these systems prioritize evolutionary threats over modern ones, researchers compared the reactions of 119 participants to images of venomous snakes, heights, firearms, and airborne diseases. The findings, published in the open-access journal PLOS One, reveal that the human body remains highly sensitive to both ancient and contemporary stressors.

Measuring Stress Through Skin Resistance

The research team utilized skin resistance measurements, which track changes in sweating, to quantify the intensity of a participant's physiological reaction. When an individual encounters a threatening stimulus, their sweating increases, which in turn decreases the skin's resistance to electrical currents. Participants were presented with photos of various threats alongside control images of neutral objects like leaves. The data showed that all threat categories elicited a significantly higher sweating response than the control images, suggesting that the body’s alert system is broadly tuned to identify and react to modern hazards as efficiently as ancestral ones.

The Intensity Disparity Between Heights and Firearms

While all threats triggered a reaction, the intensity of the response was not uniform across all categories. Ancestral threats, specifically heights and venomous snakes, prompted the most intense skin resistance responses compared to firearms and airborne disease indicators, such as medical staff in masks or individuals sneezing. Interestingly, while the frequency of reactions was similar across snakes, firearms, and disease, the physical impact of heights stood out as the most common and intense trigger. This indicates that while the body recognizes modern threats, certain evolutionary dangers still hold a unique grip on our physiological hardware.