Dr. David DeSteno on Huberman Lab: Why Prayer Cuts Cortisol

DeSteno emphasizes that God’s existence is not a scientifically useful question because we cannot manipulate God to run experiments or establish causality. The absence of empirical evidence is not evidence of absence here, because no controlled tests are possible. However, scientists can and do study the behavioral and health consequences of religious beliefs and practices, where data are very clear and often robust.

Epidemiological work (e.g., Tyler VanderWeele at Harvard) shows that people who actively engage with religion over 15–20 years have about 30% lower all-cause mortality and ~25% lower deaths from cancer and cardiovascular disease. These benefits persist even when controlling for community participation; religious community has larger effect sizes than secular clubs. Private practices like prayer and meditation also correlate with reduced anxiety and depression, especially among young adults.

Meditation significantly increased compassionate helping in DeSteno’s lab: only ~15% of non-meditators gave up a chair to someone in visible pain versus ~50% of meditators. In another paradigm, meditators refused to inflict pain on someone who angered them, while still recognizing the wrongdoing. Motor synchrony—moving, chanting, or singing in unison—causes people to feel more connected and increases willingness to help by about 30%. Religious rituals often bundle breathing, movement, narrative, and community, making them “symphonies” of life-hacks rather than isolated tricks.

Reciting structured prayers (rosary, sutras, mantras) reliably slows breathing and lengthens exhalation, increasing vagal tone, lowering heart rate, and dampening cortisol. This body state signals “safety” upward to the brain via the vagus nerve while a person contemplates fears or worries, allowing them to process distressing content without overwhelming stress physiology. This mechanism likely underlies why private prayer can protect against anxiety and why religious engagement tracks with better mental health.

In DeSteno’s cheating experiments, ~85% of people lied to secure an easy task when they could do so privately, despite unanimously calling this lying immoral in theory. But when participants first engaged in a brief gratitude exercise (“count your blessings”), cheating dropped to about 2–15% depending on the setup—a massive behavioral shift. Similarly, inducing gratitude increased willingness to help strangers, with the intensity of gratitude tracking the amount of help. Religious life, which heavily emphasizes gratitude in prayers and liturgy, likely leverages these bottom-up emotional nudges to support honesty and cooperation.