Humans did not evolve to live in large-scale societies1. Being nomadic for the lion’s share of human evolutionary history, ancestrally modern humans had important ecological constraints on group size. If you are a nomad, you can’t really move an army of 100,000 people across the mountains every few months to chase game. Before the advent of agriculture, approximately 10,000 years ago, humans lived in small-scale societies. And our minds evolved to match these prevailing social-ecological conditions4.

In a small-scale society, you know everyone. And you can expect to interact with the same individuals for the long run. In such an environment, our ancestors evolved mental capacities that were shaped by evolutionary forces to thrive in such small-scale societies. Reciprocal altruism, or the tendency to help others with an implicit expectation of receiving help back at some point, emerged as a foundational aspect of the social, emotional, and cognitive worlds of our ancestors5.

Further, under these prevailing conditions of human evolution (what some might call the EEA, or the Environment of Evolutionary Adaptedness), communication with others in one’s tribe was necessarily direct and was predominantly face-to-face. Written forms of communication didn’t emerge until well after the advent of agriculture – let alone telecommunications or internet-based communications. So for the bulk of human evolutionary history, intra-species communication in humans was of the face-to-face variety. And such communication rarely included strangers.

My how times have changed! Think about the kinds of communications that are typical today. Yes, we communicate on cell phones. Our kids communicate through video games. Facebook, online chat rooms, Snapchat, etc. etc.

Generally speaking, adults in our world today are wary about the rise of this kind of communication, with cell phone use and time spent online showing regular correlations with a variety of mental health problems6. But from the perspective of evolutionary mismatch, the problem is even worse.

How Modern Forms of Communication Differ from Ancestral Forms of Communication

An evolutionist looking at a modern problem often asks the question of mismatch, which is essentially the question of how things differ now from the way things were while our ancestors were evolving in pre-agrarian conditions. Table 1 explicates a few ways that modern forms of communications differ from ancestral forms of communications:

Comment by Anonymous

So I write a regular blog post for Psychology Today titled Darwin’s Subterranean World. And like any blogger, I usually read the comments that people leave on my posts. Some comments are more thoughtful than are others. And some comments are nicer than are others.

Based on this experience, here is a tell-tale sign that a nasty comment is about to follow: When a comment is left by “Anonymous.” When I see that, I brace myself! Regularly, these comments are nasty, often completely out of line. Often, they are equal parts incoherent rant and personal attack.

Intuitively, we can understand why. Someone who is posting anonymously to a blog probably will never meet the blogger in person. Probably has little investment in the blogger’s personal success. Further, unless the blogger is some kind of supercomputer hacker, the anonymous commenter is probably never going to “get caught.” So the possibility of retribution is very unlikely.

Of course, evolved human conditions were not like this at all! However, the “anonymous blog comment” is, as we all know, just the tip of the iceberg. These days, people are regularly, across a broad array of platforms, communicating with others in anonymous, deindividuated ways. This is a highly mismatched, unnatural way for humans to communicate with one another, and for a variety of reasons, it brings out the worst in us.

The Nasty Face of Deindividuated Behavior

Deindividuated behavior is essentially behavior that takes place under conditions when one’s individual identity is diminished. Being in a large group, using a pseudonym, hiding behind a mask – there are all kinds of ways that one’s identity might be downplayed or even fully concealed under modern conditions.

For years, social psychologists such as Zimbardo (2007) and Diener (1976) have documented the fact that people are not exactly at their best when they are in a state of deindividuation. People are less likely to be kind, more likely to be aggressive, and more likely to engage in a broad array of anti-social actions under deindividuated conditions. For this reason, evolutionary psychologist A. J. Figueredo (2006) referred to large cities, in which people are often engaging with strangers under deindividuated conditions, as breeding grounds for psychopathic behavior.

Want people to be on their worst behavior? Then put them in a deindividuated state and have all of their communications with others be fully anonymous.

Bottom Line

From the perspective of evolutionary mismatch, modern forms of social communication are more than a little problematic. Under ancestral conditions, nearly all communication was of the face-to-face variety. And it almost always included communication among individuals who have long-term bonds with one another. These days, a huge proportion of communication is of the hidden-behind-a-screen variety. And it often takes place between people who will only communicate with each other once in a lifetime. Any student of evolutionary social psychology will tell you that this is a recipe for trouble.

This understanding of modern social communication and evolutionary mismatch has implications for policy and change. All of our institutions include communications of many varieties. Cultivating face-to-face contact in communication processes in our institutions, educational, governmental, and beyond, could help address the issues delineated here. Similarly, reducing deindividuation and anonymity in communication platforms, such as those found on social media and online gaming, may well help encourage prosocial behavior among our young people.

The future belongs to all of us. We ignore our evolved nature to our own detriment.

Read the full Evolutionary Mismatch series:

  1. Introduction: Evolutionary Mismatch and What To Do About It by David Sloan Wilson
  2. Functional Frivolity: The Evolution and Development of the Human Brain Through Play by Aaron Blaisdell
  3. A Mother’s Mismatch: Why Cancer Has Deep Evolutionary Roots by Amy M. Boddy
  4. It’s Time To See the Light (Another Example of Evolutionary Mismatch) by Dan Pardi
  5. Generating Testable Hypotheses of Evolutionary Mismatch by Sudhindra Rao
  6. (Mis-) Communication in Medicine: A Preventive Way for Doctors to Preserve Effective Communication in Technologically-Evolved Healthcare Environments by Brent C. Pottenger
  7. The Darwinian Causes of Mental Illness by Eirik Garnas
  8. Is Cancer a Disease of Civilization? by Athena Aktipis
  9. The Potential Evolutionary Mismatches of Germicidal Ambient Lighting by Marcel Harmon
  10. Do We Sleep Better Than Our Ancestors? How Natural Selection and Modern Life Have Shaped Human Sleep by Charles Nunn and David Samson
  11. The Future of the Ancestral Health Movement by Hamilton M. Stapell
  12. Humans: Smart Enough to Create Processed Foods, Daft Enough to Eat Them by Ian Spreadbury
  13. Mismatch Between Our Biologically Evolved Educative Instincts and Culturally Evolved Schools by Peter Gray
  14. How to Eliminate Going to the Dentist by John Sorrentino
  15. Public Health and Evolutionary Mismatch: The Tragedy of Unnecessary Suffering and Death by George Diggs
  16. Is Shame a Bug or a Feature? An Applied Evolutionary Approach by Nando Pelusi
  17. The “Benefits,” Risks, and Costs of Routine Infant Circumcision by Stephanie Welch
  18. An Evolutionary Perspective on the Real Problem with Increased Screen Time by Glenn Geher
  19. Did Paleolithic People Suffer From Kidney Disease? by Lynda Frassetto
  20. The Physical Activity Mismatch: Can Evolutionary Perspectives Inform Exercise Recommendations? by James Steele


  1. Diener, E., Fraser, S. C., Beaman, A. L., and Kelem, R. T. (1976). “Effects of Deindividuation Variables on Stealing Among Halloween Trick-or-Treaters,” Journal of Personality and Social Psychology, 33, 178-183.
  2. Dunbar, R. I. M. (1992). “Neocortex Size as a Constraint on Group Size in Primates,” Journal of Human Evolution, 22(6), 469–493.
  3. Figueredo, A. J., Vásquez, G., Brumbach, B. H., & Schneider, S. M. R. (2006b). “The Heritability of Life History Strategy: The K-factor, Covitality, and Personality,” Social Biology 51(3-4), 121-43.
  4. Geher, G. (2014). Evolutionary Psychology 101. New York: Springer.
  5. Trivers, R. (1985). Social Evolution. Menlo Park, CA: Benjamin/Cummings.
  6. Twenge, J. (2017). Why Today’s Super-Connected Kids Are Growing Up Less Rebellious, More Tolerant, Less Happy–and Completely Unprepared for Adulthood–and What That Means for the Rest of Us. New York: Simon and Schuster.
  7. Zimbardo, P. (2007). “The Lucifer Effect: Understanding How Good People Turn Evil,” The Journal of The American Medical Association. 298 (11): 1338–1340.

Published On: February 24, 2020

Glenn Geher

Glenn Geher

Glenn Geher is Professor of Psychology as well as Founding Director of Evolutionary Studies at the State University of New York at New Paltz. Glenn has taught several courses at the undergraduate and graduate levels – including Statistics, Social Psychology, and Evolutionary Psychology – and has won the New Paltz Alumni Association’s Distinguished Teacher of the Year Award, along with Chancellor’s Awards for both Teaching and Research Excellence from the State University of New York. First and foremost, Glenn is a teacher, and his primary goal is to educate and support his students and work to facilitate their success as they develop across their careers.


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