The Effects of Psychological Biases and Social Media on Nuclear War Decisions


By Andrew Quist

In a recent paper, psychologist Paul Slovic and security scholar Herb Lin identify several psychological and social mechanisms that may lead to nonrational decision making concerning the use of nuclear weapons, including psychic numbing and the prominence effect. Slovic and Lin also write that the rise of social media has increased the risk that decision makers will make a mistake in ordering the use of nuclear weapons. Their paper is titled “The Caveman and the Bomb in the Digital Age,” and it was commissioned by the Stanley Foundation for a workshop on “Effects of the Global Information Ecosystem on the Risk of Nuclear Conflict.” A summary of the paper is below. You can read the full paper here.

Psychological factors influencing nuclear war decisions

Psychic numbing reduces the perceived importance of large numbers of lives. This bias acts upon national security decision makers by desensitizing them to the consequences of their decisions. Psychic numbing is evident in the fire-bombing of Tokyo, Dresden, and many other cities during World War II, as well as General Curtis Lemay’s desire, soon after the end of that war, to preemptively drop 750 atomic bombs on targets in the Soviet Union.

Public opinion concerning nuclear weapons also demonstrates psychic numbing. In an experiment conducted in 2015, a clear majority of Americans surveyed said they would approve of the use of nuclear weapons against the civilian population of Iran in a hypothetical war between the U.S. and Iran (Sagan & Valentino, 2017). There was no loss of public support for the use of nuclear weapons when the projected loss of lives among Iranian civilians increased from 100,000 to 2,000,000.

The prominence effect suggests that high priority objectives like national security draw attention away from less prominent goals like protecting foreign civilian lives. The prominence effect was likely operative in the Truman administration’s decisions to drop atomic bombs on Hiroshima and Nagaskai.

Psychic numbing and security prominence are typically accompanied by dehumanization and blaming of the victims, further allowing mass killing to proceed without challenge from normal feelings of abhorrence that one would expect to prevent such atrocities.

The impact of social media

Slovic and Lin write that along with biases due to psychic numbing and the prominence effect, the social media environment poses challenges for responsible decision making in times of crisis between nuclear-armed parties. Social media increases the velocity of information transmission, and the lack of fact-checking leaves social media platforms susceptible to disinformation and misinformation. Also, because social media postings tend to be short and rich in visual and emotion-laden content, they are likely to be processed with fast, intuitive thought rather than reflective, deliberate thought. These vulnerabilities pose challenges for people considering the use of nuclear weapons, as well as the people charged with carrying out those orders.

Possible solutions

Slovic and Lin suggest several ways to ensure that psychic numbing and other psychological mechanisms do not lead to nonrational decision making in times of nuclear crises, such as using decision analytic procedures, eliminating launch on warning options from nuclear war plans, and requiring that at least one party other than the president assent to decisions to use nuclear weapons.

Works Cited

Sagan, S. D., & Valentino, B. A. (2017). Revisiting Hiroshima in Iran: What Americans really think about using nuclear weapons and killing noncombatants. International Security, 42(1), 41–79.

Slovic, P., & Lin, H. (2018, September). The caveman and the bomb in the digital age. In Effects of the global information ecosystem on the risk of nuclear conflict. Workshop conducted at the Center for International Security and Cooperation, Stanford University, Stanford, CA. Available at