Final answer:
Behavioral modernity, characterized by cognitive traits and sophisticated cultural behaviors, is mainly associated with Homo sapiens, which appeared about 200,000 years ago. Earlier hominins like Homo erectus and Homo naledi had some modern traits but did not show the full range of behaviors associated with modern humans.
Step-by-step explanation:
The term behavioral modernity refers to a suite of behavioral and cognitive traits that distinguishes the Homo sapiens species from other hominins. While some hominins like Homo neanderthalensis used tools and may have worn clothing, suggesting some degree of behavioral complexity, the full suite of behavioral modernity is typically associated with Homo sapiens. These traits include symbolic thought, artistic expression, and the development of sophisticated tools. This defines a phase in the evolution of Homo sapiens known as "anatomically modern humans," which arose approximately 200,000 years ago in Africa.
Earlier hominins, such as Homo erectus and Homo naledi, exhibited a combination of ancient and modern traits. From the neck down, their fossil remains show adaptations for bipedalism, with foot morphology nearly indistinguishable from modern human feet. Yet from the neck up, these hominins had larger jaws and teeth, sloping foreheads, and small brains compared to modern humans. Although they were efficient walkers, they did not exhibit the full range of behavioral modernity seen in later Homo sapiens.
It's also important to note that while Australopithecus species were bipedal, their brain sizes and body proportions were more akin to great apes than modern humans. The fossil footprints found in Laetoli, Tanzania, dated to 3.6 million years ago, suggest that bipedalism was present among these earlier hominins, but it is with the emergence of Homo sapiens that we see the clear evidence of behavioral modernity.