Behavioral Modernity vs. Complexity: What Stone Tools Teach Us

European paleoanthropologists developed the behavioral modernity metaphor in the 1970s, when it became clear that the archaeological record for human origins in Europe 45,000 years ago differed from that found with older “archaic” humans in Africa and Asia. Since then, archaeologists have defined behavioral modernity strategically, varying diagnostic criteria to draw attention to one or another kind of evidence. Many have cited the use of projectile weaponry as evidence for modern human behavior and cognition, but changes in projectile weaponry do not correlate with any major inflection point in human evolution. This should surprise no one, because the projectile technology-behavioral modernity link rests on little or no prior theory. Archaeologists developed it after-the-fact to explain early evidence for projectile technology. Rather than focusing on behavioral modernity, paleoanthropologists should focus on behavioral complexity. Complexity is a metaphor, too, but it is also a statistically-measurable property of any quantitative evidence. The stone tool record begins to exhibit increasingly complex variability after 0.2-0.3 million years ago, during a period correlated with Homo sapiens origin and dispersal. This complex variability most likely reflects an evolving relationship between technology and spoken language –an uniquely derived human behavior, that intensified as humans became Earth’s only obligatory tool-using primate.