Behavioral modernity


Behavioral modernity refers to a suite of behavioral and cognitive traits associated with Homo sapiens, reflecting capacities such as abstract and symbolic thought, planning depth, cumulative culture, and complex social learning. These traits are often inferred archaeologically through evidence including symbolic artifacts, ritualized behavior, music and dance, sophisticated hunting strategies, and advanced lithic technologies such as blade production. Rather than representing an absolute boundary between Homo sapiens and other hominins, behavioral modernity is increasingly understood as a mosaic of traits that emerged gradually and were expressed variably across time and populations.

Evolution

possessed much of the necessary neural architecture by at least ~300 thousand years ago, but early populations were small and fragmented, limiting the persistence and transmission of complex behaviors. As a result, archaeological signals of symbolism, art, and advanced technologies appear sporadically in Africa between ~150–75 kya, reflecting intermittent expression, even though the cognitive capacity was probably present. Widespread, continuous manifestations of these behaviors became archaeologically visible only after populations grew denser and social networks expanded, appearing across continents, one instance being during the Upper Paleolithic in Europe.
In this view, behavioral modernity is primarily cultural and learned, shaped by high-fidelity social learning, cumulative culture, and demographic thresholds, while resting on an evolved cognitive substrate that predates its full material expression. Differences between Homo sapiens and other hominins are therefore understood as differences of degree, stability, and cultural accumulation, not the presence or absence of a single cognitive mutation.
Underlying these behaviors and technological innovations are cognitive and cultural foundations that have been documented experimentally and ethnographically by evolutionary and cultural anthropologists. These human universal patterns include cumulative cultural adaptation, social norms, language, and extensive help and cooperation beyond close kin.
Within the tradition of evolutionary anthropology and related disciplines, it has been argued that the development of these modern behavioral traits, in combination with the climatic conditions of the Last Glacial Period and Last Glacial Maximum causing population bottlenecks, contributed to the evolutionary success of Homo sapiens worldwide relative to Neanderthals, Denisovans, and other archaic humans.
There are many other theories on the evolution of behavioral modernity. These approaches tend to fall into two camps: cognitive and gradualist. The Later Upper Paleolithic Model theorizes that modern human behavior arose through cognitive, genetic changes in Africa abruptly around 40,000–50,000 years ago around the time of the Out-of-Africa migration, prompting the movement of some modern humans out of Africa and across the world.
Other models focus on how modern human behavior may have arisen through gradual steps, with the archaeological signatures of such behavior appearing only through demographic or subsistence-based changes. Many cite evidence of behavioral modernity earlier namely in the African Middle Stone Age. Anthropologists Sally McBrearty and Alison S. Brooks have been notable proponents of gradualism—challenging Europe-centered models by situating more change in the African Middle Stone Age—though this model is more difficult to substantiate due to the general thinning of the fossil record as one goes further back in time.

Definition

To classify what should be included in modern human behavior, it is necessary to define behaviors that are universal among living human groups. Some examples of these human universals are abstract thought, planning, trade, cooperative labor, body decoration, and the control and use of fire. Along with these traits, humans possess much reliance on social learning. This cumulative cultural change or cultural "ratchet" separates human culture from social learning in animals. In addition, a reliance on social learning may be responsible in part for humans' rapid adaptation to many environments outside of Africa. Since cultural universals are found in all cultures, including isolated indigenous groups, these traits must have evolved or have been invented in Africa prior to the exodus.
Archaeologically, a number of empirical traits have been used as indicators of modern human behavior. While these are often debated a few are generally agreed upon. Archaeological evidence of behavioral modernity includes:
Several critiques have been placed against the traditional concept of behavioral modernity, both methodologically and philosophically. Anthropologist John Shea outlines a variety of problems with this concept, arguing instead for "behavioral variability", which, according to the author, better describes the archaeological record. The use of trait lists, according to Shea, runs the risk of taphonomic bias, where some sites may yield more artifacts than others despite similar populations; as well, trait lists can be ambiguous in how behaviors may be empirically recognized in the archaeological record. In particular, Shea cautions that population pressure, cultural change, or optimality models, like those in human behavioral ecology, might better predict changes in tool types or subsistence strategies than a change from "archaic" to "modern" behavior. Some researchers argue that a greater emphasis should be placed on identifying only those artifacts which are unquestionably, or purely, symbolic as a metric for modern human behavior.
Since 2018, recent dating methods utilized on various cave art sites in Spain and France have shown that Neanderthals performed symbolic artistic expression, consisting of red "lines, dots, and hand stencils" found in caves, prior to contact with anatomically modern humans. This is contrary to previous suggestions that Neanderthals lacked these capabilities.

Theories and models

Late Upper Paleolithic Model or "Upper Paleolithic Revolution"

The Late Upper Paleolithic Model, or Upper Paleolithic Revolution, refers to the idea that, though anatomically modern humans first appear around 150,000 years ago, they were not cognitively or behaviorally "modern" until around 50,000 years ago, leading to their expansion out of Africa and into Europe and Asia. These authors note that traits used as a metric for behavioral modernity do not appear as a package until around 40–50,000 years ago. Anthropologist Richard Klein specifically describes that evidence of fishing, tools made from bone, hearths, significant artifact diversity, and elaborate graves are all absent before this point. According to both Shea and Klein, art only becomes common beyond this switching point, signifying a change from archaic to modern humans. Most researchers argue that a neurological or genetic change, perhaps one enabling complex language, such as FOXP2, caused this revolutionary change in humans. The role of FOXP2 as a driver of evolutionary selection has been called into question following recent research results.
The African Middle Stone Age period gives us some of the earliest evidence of Behavioral Modernity. In Southern Africa, groups of people would bypass closer deposits of rich, deep-red ochre in favor of mining more distant ones. After mining, pieces of ochre would show evidence of grinding to make a powder, which indicates that ochre was being ground for a reason other than simply for decoration. In North Africa, similar early evidence of behavioral modernity can be seen in the 82,000-year-old Taforalt cave where the perforation of marine shells was for the construction of necklaces. It was noted that the cave was very inland, which implies the presence of a trade network in the area where people were able to acquire shells of the coastal Nassarius species. People wore the beads along with the necklace, and evidence of wear showed that the bead was a personal ornament, which indicates behavioral modernity. In Africa, the evidence presents behavioral modernity in the form of symbolism, personal ornamentation, and the movement of trade in necklace beads. All this occurred in Africa 10s of thousands of years before these behaviors appeared in Europe. These results dispute older models that relocated the origin of modern behavior to the Upper Paleolithic period and the 'sudden' appearance of the behaviors to Africa.
Building on the FOXP2 gene hypothesis, cognitive scientist Philip Lieberman has argued that proto-language behaviour existed prior to 50,000 BP, albeit in a more primitive form. Lieberman has advanced fossil evidence, such as neck and throat dimensions, to demonstrate that so-called "anatomically modern" humans from 100,000 BP continued to evolve their SVT, which already possessed a horizontal portion capable of producing many phonemes which were mostly consonants. According to his theory, Neanderthals and early Homo sapiens would have been able to communicate using sounds and gestures.
From 100,000 BP, Homo sapiens necks continued to lengthen to a point, by around 50,000 BP, where Homo sapiens necks were long enough to accommodate a vertical portion to their SVT, which is now a universal trait among humans. This SVTv enabled the enunciation of quantal vowels: ; ; and . These quantal vowels could then be immediately put to use by the already sophisticated neuro-motor-control features of the FOXP2 gene to generate more nuanced sounds and in effect increase by orders of magnitude the number of distinct sounds that can be produced, allowing for fully symbolic language.
Goody draws an analogy between the development of spoken language and that of writing: the shift from pictographic or ideographic symbols into a fully abstract logographic writing system, or from a logographic system into an abjad or alphabet, led to dramatic changes in human civilization.
Contrasted with this view of a spontaneous leap in cognition among ancient humans, some anthropologists like Alison S. Brooks, primarily working in African archaeology, point to the gradual accumulation of "modern" behaviors, starting well before the 50,000-year benchmark of the Upper Paleolithic Revolution models. Howiesons Poort, Blombos, and other South African archaeological sites, for example, show evidence of marine resource acquisition, trade, the making of bone tools, blade and microlithic technology, and abstract ornamentation at least by 80,000 years ago. Given evidence from Africa and the Middle East, a variety of hypotheses have been put forth to describe an earlier, gradual transition from simple to more complex human behavior. Some authors have pushed back the appearance of fully modern behavior to around 80,000 years ago or earlier in order to incorporate the South African data.
Others focus on the slow accumulation of different technologies and behaviors across time. These researchers describe how anatomically modern humans could have been cognitively the same, and what we define as behavioral modernity is just the result of thousands of years of cultural adaptation and learning. Archaeologist Francesco d'Errico, and others, have looked at Neanderthal culture, rather than early human behavior exclusively, for clues into behavioral modernity. Noting that Neanderthal assemblages often portray traits similar to those listed for modern human behavior, researchers stress that the foundations for behavioral modernity may in fact, lie deeper in our hominin ancestors. If both modern humans and Neanderthals express abstract art and complex tools then "modern human behavior" cannot be a derived trait for our species. They argue that the original "human revolution" theory reflects a profound Eurocentric bias. Recent archaeological evidence, they argue, proves that humans evolving in Africa some 300,000 or even 400,000 years ago were already becoming cognitively and behaviourally "modern". These features include blade and microlithic technology, bone tools, increased geographic range, specialized hunting, the use of aquatic resources, long-distance trade, systematic processing and use of pigment, and art and decoration. These items do not occur suddenly together as predicted by the "human revolution" model, but at sites that are widely separated in space and time. This suggests a gradual assembling of the package of modern human behaviours in Africa, and its later export to other regions of the Old World.
Between these extremes is the view—currently supported by archaeologists Chris Henshilwood, Curtis Marean, Ian Watts and others—that there was indeed some kind of "human revolution" but that it occurred in Africa and spanned tens of thousands of years. The term "revolution," in this context, would mean not a sudden mutation but a historical development along the lines of the industrial revolution or the Neolithic revolution. In other words, it was a relatively accelerated process, too rapid for ordinary Darwinian "descent with modification" yet too gradual to be attributed to a single genetic or other sudden event. These archaeologists point in particular to the relatively explosive emergence of ochre crayons and shell necklaces, apparently used for cosmetic purposes. These archaeologists see symbolic organisation of human social life as the key transition in modern human evolution. Recently discovered at sites such as Blombos Cave and Pinnacle Point, South Africa, pierced shells, pigments and other striking signs of personal ornamentation have been dated within a time-window of 70,000–160,000 years ago in the African Middle Stone Age, suggesting that the emergence of Homo sapiens coincided, after all, with the transition to modern cognition and behaviour. While viewing the emergence of language as a "revolutionary" development, this school of thought generally attributes it to cumulative social, cognitive and cultural evolutionary processes as opposed to a single genetic mutation.
A further view, taken by archaeologists such as Francesco d'Errico and João Zilhão, is a multi-species perspective arguing that evidence for symbolic culture, in the form of utilised pigments and pierced shells, are also found in Neanderthal sites, independently of any "modern" human influence.
Cultural evolutionary models may also shed light on why although evidence of behavioral modernity exists before 50,000 years ago, it is not expressed consistently until that point. With small population sizes, human groups would have been affected by demographic and cultural evolutionary forces that may not have allowed for complex cultural traits. According to some authors, until population density became significantly high, complex traits could not have been maintained effectively. Some genetic evidence supports a dramatic increase in population size before human migration out of Africa. High local extinction rates within a population also can significantly decrease the amount of diversity in neutral cultural traits, regardless of cognitive ability.