Source: CCO Public Domain / Pixabay

When I first heard about the twin towers on September 11, 2001, I was in shock. I was in my house about an hour north of NYC and was watching cartoons (that got interrupted) with my then-11-month-old daughter at the time. I had to turn off the TV. As a relatively sensitive person, I was shocked, scared, and out in ways that I’d never been before.

The more recent Paris attacks and the numerous similar attacks that seem to be part of “the new normal” (e. ., peace rally in Ankara, the bus in Tunisia, the trains of Madrid, etc.) are often carried out with precisely the goal of creating “terror”—creating adverse psychological consequences for large numbers of people.

Terrorist Acts Exploit our Evolved Psychology

The big-ticket terrorist acts—the ones that hijack the news stations for days on end and that cause regular people to change their travel plans and work schedules out of —are partly effective because they exploit deeply evolved features of human psychology. The stress, fear, and horror that such acts bring about on a large scale represent an exploitation of the evolution of the human mind.

Super-Normal Stimuli and Evolved Behaviors

Decades ago, famed ethologist Niko Tinbergen (1953) documented what he called “super-normal stimuli” in studying herring gull chicks and their interactions with their parents. His research started by asking why adult herring gulls have small red patches on their beaks. Through careful experimental methods, Tinbergen came to find that the red patch served as a stimulus for helpless hatchlings. One simple rule that hatchlings seem to have down is this: If you see red, put out your beak. Well this rule has an adaptive effect for herring gull hatchlings—their parents’ beaks (that include the red stimuli) are where the food is. So striking toward red stimuli was “selected” as an adaptive behavioral trait—it led to effective eating.

In now-classic research on this topic, Tinbergen manipulated the amount of red on various artificial beaks—and came to find that there seemed to be a “the-more-red-the-better” rule built into these creatures. Beaks with 10 times the amount of red found in natural adult beaks led to an increase in interest and on the part of hatchlings. These very red artificial beaks, then, can be thought of as super-normal stimuli. Super-normal stimuli essentially have exaggerated features of stimuli that evolved for some adaptive purpose.

In humans, we see effects of super-normal stimuli all the time. Just as herring gull hatchlings evolved to prefer pecking at red stimuli, humans evolved to prefer foods that are high in sugar content. This preference evolved because under low-resource conditions (which were common ancestrally), it was adaptive and would lead to eating foods that could help one survive famine conditions. But now we have things like milkshakes from McDonald’s. A milkshake is, in essence, a super-normal stimulus. It includes sugar content that is magnitudes more concentrated than any sugar-rich food would have been under ancestral conditions. A McDonald’s milkshake is like one of Tinbergen’s super-red artificial beaks. It works because it exploits the fact that we evolved a simple rule of “prefer sugary foods” due to such a rule being adaptive for our ancestors.

Much in the way of human vices, in fact, can be thought of in terms of the large-scale production of super-normal stimuli that exploit human evolved psychology. McDonald’s and the junk-food industry in general is but one example. clearly represents another example—including sexual stimuli in large quantities that totally exploit evolved -relevant psychology. Facebook, Instagram, and other forms of social media also can be thought of as comprising a battery of super-normal stimuli—exploiting the evolved human motives for connection and social approval.

Terrorist Acts as Super-Normal Stimuli

Under ancestral conditions, nothing quite like the Paris attacks ever could have happened. While terrible things, including acts of violence, have always been part of the human story (see Pinker, 2011), the small-scale societies of our pre-agrarian ancestors didn’t have the population numbers or the technologies that underlie events such as the Paris attacks or 9/11.

Humans have strong negative reactions to blood and gore (see Bildhauer, 2013)—and these reactions make sense from an evolutionary perspective. Not only do blood and gore possibly signal loss of significant others in one’s life, but they also signal possible threat to oneself, and they signal the possibility of large-scale pathogen prevalence in one’s area. For various reasons, then, we have evolved to have adverse, stressed reactions to the sight of blood and gore.

Partly capitalizing on the evolutionarily novel reality of modern media, large-scale acts of terror exploit this tendency for humans to be stressed by blood and gore—creating sensationalist, super-normal versions of such stimuli. In events such as the Paris attacks or 9/11, huge numbers of people are exposed to images of blood and gore that are well-beyond what our ancestors would have ever experienced. These images are, thus, super-normal stimuli—they affect us due to our species’ evolutionary history with such stimuli. In the case of such acts of terror, they represent an evolutionarily novel superdose of such stimuli—leading to stress, fear, and on a scale that is much larger than would have ever been the case under ancestral conditions. In short, those who design and implement such acts of terror are hijacking our evolved psychology by creating super-normal stimuli that lead to unnatural adverse psychological outcomes on a large scale.

Bottom Line

When something terrible happens, humans go into the mode of attributional reasoning—trying to figure out why and how this terrible thing could have possibly happened. In thinking about the recent acts of terror in places such as Ankara and Paris, it occurs to me that the people behind these atrocities are exploiting natural features of the human mind. Acts of terror create large-scale states of terror and stress because such acts and their widely disseminated results represent stimuli that are considerably beyond what our ancestors would have experienced in their normal lives. From an evolutionary perspective, then, the reality of terrorism can be thought of as yet another example of how evolutionary mismatch between ancestral and current conditions adversely affects our modern lives.

References and Acknowledgment

Bildhauer, B. (2013). Medieval European conceptions of blood: Truth and human integrity. Journal of the Royal Anthropological Institute, 19(S1), 57-76.

Pinker, S. (2011). The Better Angels of our Nature. New York, NY: Viking

Tinbergen, N. 1953. The Herring Gull's World. London: Collins.

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This piece would not be possible without the work of my awesome student, Nate Postol. Nate is an undergraduate honors student at SUNY New Paltz and is a member of the SUNY New Paltz Lab. He has been working on a top-shelf thesis related to super-normal stimuli for several semesters now - and my conversations with Nate provided much in the way of inspiration for this article.