This image was taken from Stanley Kubrick's 1968 film, 2001: A Space Odyessey.

THE EARLY STONE AGE (~3 Ma)

The Creation of Tools and Evolution of Early Hominids

Stone tools have been used by primates for millions of years, but the Lomekwi artifacts represented a marked shift in the cognitive abilities of the very hominids whose lineage would eventually lead to Homo sapiens. It's well-known by primatologists that chimps and other primates crack nuts with stone hammers and capture ants with wands and probes [1]. This intriguing primate ability to use tools can also clue us in to how our ancient ancestors acted, considering our homonin lineage likely diverged "from those leading to chimpanzees, bonobos, and gorillas at around 8–6 Ma" [2]. Given this family history, it shouldn't be surprising that our ape-like ancestors would resemble our closest hominid cousins that are still around today. More to the point, these ancestors from 3.3 Ma created the much-discussed Lomekwi artifacts which were quite primitive, as are the tools used by modern chimps. That being said, the Lomekwian industry was still more advanced than anything a chimp has ever produced as it included tools which have been carved and shaped using other materials. This complexity could be due to the fact that the hands of some hominids in the Lomekwi era (like the Australopithecus africanus) allowed for more technological versatility– from precisely manipulating small tools to throwing a fastball. Meanwhile, chimp hands are unable to do these things because their wrists lock “to prevent overextension during knuckle walking” [3].

The Oldowan Artifacts

Australopithecines in the Oldowan continued to make technological advancements that not only helped them gather food, but also changed the shape of their bodies over time and forced them to rely more on teamwork to survive. The Olodwan stone artifacts, created around 2.5 Ma, were more advanced than the Lomekwi ones since they included lumps of stone that were sharpened for butchery and marrow extraction purposes. Not only that, but the tools were clearly used for more than just hunting. These prehistoric engineers were interested in creating instruments that would help them cut up plants rather than just meat (refer back to [3]). More importantly, the creation of tools in the ESA spurred the evolution of australopithecines as they began relying more on technology and teamwork to survive in the “competitive and unpredictable environments of the African savanna” [4]. Intriguingly, this reliance on technology changed the bodies of these ancient primates, as seen with the Australopithecus africanus whose hands adapted over time thereby allowing them to manipulate small tools.

The Acheulean Artifacts

Hominids in the Acheulean were much more intelligent than their Oldowan predecessors, as demonstrated by their technological advancements and newfound ability to harness fire. Acheulean hominids (i.e. Homo erectus), who lived around 1 to 1.5 Ma, had greater cognitive abilities than the australopithecines in the Oldowan as they created large cutting tools like spears as well as handaxes with standardized shapes, all in different sizes. This correlated with increased brain size [5], and it begs the question: did hominids become smarter becuase they were using tools, or did they begin using tools as they gained intelligence through some other means? For example, this was also the time that they discovered how to systematically use fire, thereby "substantially" improving the nutritional qualities of the meat and plants they were eating. Thus, it could be that their improved diet would assist in the development of their intelligence which would then allow them to make more advanced tools. Overall, this mystery presents a chicken or the egg scenario in which we must determine whether tool use preceeded evolved mental capacities, or vice versa. But putting this dilemma aside, what finally marked the shift between the ESA and MSA was the use of "heavy-duty" woodwork when creating axes, picks, and lances with thick cores [6].

THE MIDDLE STONE AGE (~300 ka)

Technological and cultural evolution accelerated when MSA hominids did away with bulky and cobbled-together tools while favoring more refined technologies. Not only did the stone toolkit in the MSA introduce a large variety of blade technology, but it was also of better quality than anything from the Acheulean industry [7]. This was a time of accelerated technological and cultural evolution which was spurred by "Neanderthals, late archaic humans, and anatomically modern humans” (refer back to [6]). Large cutting tools and other bulky weapons were quickly replaced with smaller tools that had more stable and robust cores. They introduced stone-tipped spears, knives, and scrapers— technologies that were light years beyond what was produced in the Acheulean and what the surrounding primates were doing at the time (ibid.).

THE LATER STONE AGE (~35 ka)

The humans of the LSA used a great assortment of materials to create novel tools, and they engaged in many activities that are reminiscent of how modern humans express themselves. During this era, humans created more harpoons, a variety of projectiles, awls, needles, and even ornaments using a diverse range of materials— from ivory and antlers to shells and stones. Such polished artifacts were rare in the MSA, but commonplace in the LSA [8]. These tools were quite efficient and uniform in size, thereby suggesting that their creators were far more organized than previous generation. While these tools were mainly used for hunting and gathering [9], some were developed to assist in transportation. Cordage, for example, was probably invented to sail to new continents like Australia [10]. On top of this, the LSA was characterized by activities that are similar to how modern humans express themselves, including the production of art; self decoration involving ochre and beads; religious beliefs and rituals; the formation of strategic social alliances; sophisticated architecture; and so on (refer back to [8] and [9]). But more on this later.

1. For more information on the use of tools among primates, see Ambrose, "Paleolithic Technology and Human Evolution," pp. 1748-9.
2. Kiura, "Stone Age Cultures of East Africa," p. 70.
3. Ambrose, "Paleolithic Technology and Human Evolution," p. 1749.
4. ibid., p. 1750.
5. Ambrose, "Paleolithic Technology and Human Evolution," p. 1750; Kiura, "Stone Age Cultures of East Africa," p. 73.
6. Ambrose, "Paleolithic Technology and Human Evolution," p. 1751.
7. Kiura, "Stone Age Cultures of East Africa," p. 73.
8. Ambrose, "Paleolithic Technology and Human Evolution," p. 1752.
9. Kiura, "Stone Age Cultures of East Africa," pp. 73-4.
10. Wong, "The Caveman's New Clothes," p. 34.