This article accompanies a This View of Life Podcast with PsychTable co-founders Niruban Balachandran and Daniel Glass. Listen here.

In 1992, the evolutionary psychologists Leda Cosmides and John Tooby predicted, "Just as one can now flip open Gray's Anatomy to any page and find an intricately detailed depiction of some part of our evolved species-typical morphology, we anticipate that in 50 or 100 years one will be able to pick up an equivalent reference work for psychology and find in it detailed information-processing descriptions of the multitude of evolved species-typical adaptations of the human mind, including how they are mapped onto the corresponding neuroanatomy and how they are constructed by developmental programs."

Classification systems like the one Cosmides and Tooby envisaged indicate the maturity of a scientific discipline because they enable the organization and labeling of entities under observation (i.e., taxa). Like chemistry’s Periodic Table of Elements, zoology’s Linnean classification system, and psychiatry’s Diagnostic and Statistical Manual of Mental Disorders, the evolutionary behavioral sciences were still in need of a taxonomy of evolved psychological adaptations (EPAs)—which are defined as cognitive, emotional, behavioral, or perceptual traits that were functionally designed by the process of evolution by selection—such as the eyeblink, thirst, and startle responses.

However, by the start of the 21st century, evolutionary behavioral scientists had already proposed and amassed an international stock of hundreds of EPAs. Furthermore, other factors signaled that the timing was right for establishing a classification system for EPAs: an abundance of affordable global computing power, the explosion in web-based scientific collaboration and social networking, increasingly testable hypotheses, exciting new research methods from advanced neuroimaging to behavioral genetics, and the international emergence of a core of young, transdisciplinary researchers. Therefore, finding it unnecessary to wait until 2042 or 2092, Niruban proposed and published a taxonomy of human EPAs in 2011. We then teamed up in 2012, co-founding and announcing the launch of together. It was a terrific moment.

Psychology, neurobiology, anthropology, behavioral ecology, sociology, human ethology—these disciplines all aim to understand the workings of the human mind, brain, and behavior. Yet despite common empirical objectives, each branch of knowledge has its own collection of academic departments, journals, terminologies, methodologies, and research traditions—an epistemological Tower of Babel. Despite the global drive toward interdisciplinarity in empirical research, cross-pollination and collaboration in universities and higher education institutions can be surprisingly rare.

The consilience of the evolutionary and behavioral sciences has provided researchers with a powerful approach to understanding human nature. Nevertheless, since the evolutionary behavioral sciences lack a centralized, authoritative classification system to organize, evaluate, and present the accumulated body of knowledge, unfortunately, the most cutting-edge research on the human mind tends to be locked away behind online paywalls—balkanized across journal articles, papers, and books of varying quality, prominence, and accessibility. Therefore, an open-science, collaborative approach to can yield better research, teaching, and student learning outcomes. In addition, an open-science approach can address perennial empirical challenges such as reproducibility, impact factor manipulation, p-value hacking, hypothesis generation, and didactic utility.

As E.O. Wilson wrote, “To maintain the species indefinitely, we are compelled to drive toward total knowledge, right down to the levels of the neuron and the gene. When we have progressed enough to explain ourselves in these mechanistic terms, and the social sciences come to full flower, the result might be hard to accept.” Therefore, to address this imperative, our goals are fourfold:

  1. Increase awareness of the role evolution has played in shaping our minds, brain, and behavior.
  2. Create a simple and intuitive taxonomy of proposed and supported EPAs.
  3. Help identify gaps in current EPA research.
  4. Provide a reference tool for scientists, students, and laypeople studying human behavior.

One way to help accomplish the above objectives is to provide PsychTable users with ways to evaluate the strength of evidence for EPAs—namely, their evidentiary depth and breadth. For PsychTable, evidentiary depth is described as the quality of the research studies marshaled as evidence for the evolutionary roots of a given EPA. For example, Schmitt and Pilcher propose that a “minimal” level of evidentiary depth might be the appropriate ranking for single research studies with one mode of measurement, poor methodological control, and unrepresentative sampling. At the other end of the research-quality spectrum, they propose that “exemplary” levels of evidentiary depth might be the appropriate ranking for lines of evidence with dozens of research studies with multiple modes of measurement, the highest levels of control, and true representative sampling.

For PsychTable, evidentiary breadth is described as how many lines of evidence a hypothesized EPA has. To offer one example, in his book The Expression of the Emotions in Animals and Man, Charles Darwin himself happily observed that his grinning baby boy "understood a smile and received pleasure from seeing one, answering it by another, at much too early an age to have learned anything by experience." A genuine smile reflects one of the most rewarding feelings that humans can experience in their lifetimes, and in order to discover its evolutionary roots, for example, we can now ethnographically observe the extent to which a smile is a cross-cultural human universal, document its occurrence in indigenous hunter-gatherer societies, discover its neurochemical substrates, observe how smiling occurs in neonates independent of socialization or learning, examine its cross-species homologies in primates and conspecifics, and map a genuine smile’s musculature through the Facial Action Coding System (FACS). As Cosmides and Tooby predicted, when research methods sufficiently advance, not only will we be able to map EPAs’ developmental programs, but we will also be able to trace how EPAs fall into complex brain systems with overlapping, embedded, nested, and shared processes among them. Eventually, will reflect these and other cognitive complexities.

As for our most recent progress to date, we have published two peer-reviewed research papers about in scientific journals here and here, with a third currently under review. In addition, we have formed a superbly talented team and have made available a working set of user-experience wireframes here, which capture the website’s projected look and feel. We have also earned extensive support and endorsements from a wide range of scientists and academic organizations and have built an extensive international network of researchers and students who are awaiting the site’s launch so they may begin using it. Finally, we have so far crowdfunded approximately $2,316 out of $10,000 in order to hire the highly experienced web designers and developers needed to create a robust and intuitive web interface. To help us crowdfund toward this target, interested TVOL readers can donate to here.

Over the past few decades, the international evolutionary behavioral science research community has managed to adroitly revolutionize numerous fields of scientific inquiry. Evolution has also empowered us to test hypotheses about human nature in creative and exhilarating ways. is, therefore, an open-science taxonomy devoted to uncovering the richness and complexity of our evolved human behavior. We hope it will help contribute to a fuller understanding of ourselves and our world. As W.D. Hamilton put it, “The tabula of human nature was never rasa, and is now being read.”