The Later Stone Age (or LSA) is a period in African prehistory that follows the Early Stone Age and Middle Stone Age. All three periods are often confused with the Lower Paleolithic, Middle Paleolithic, and Upper Paleolithic. In the 1920s, it became clear to archaeologists that the existing chronological system of Upper, Middle, and Lower Paleolithic was not a suitable correlate to the prehistoric past in Africa.
The terms Early, Middle, and Later Stone Age were developed to address this issue. Some scholars, however, still view these two chronologies as parallel, arguing that they both represent the development of behavioral modernity. The Later Stone Age is associated with the advent of modern human behavior in Africa, although definitions of this concept and means of studying it are up for debate. The transition from the Middle Stone Age to the Later Stone Age is thought to have occurred first in eastern Africa between 50,000 and 39,000 years ago. It is also thought that Later Stone Age peoples and/or their technologies spread out of Africa over the next several thousand years.
Originally, the Later Stone Age was defined as several stone industries and/or cultures which included other evidence of human activity, such as ostrich eggshell beads and worked bone implements, and lacked Middle Stone Age stone tools other than those recycled and reworked. LSA peoples were directly linked with biologically and behaviorally modern populations of hunter/gatherers, some being directly identified as San "Bushmen." This definition has changed since its creation with the discovery of ostrich eggshell beads and bone harpoons in contexts which predate the LSA by tens of thousands of years. The Later Stone Age was also long distinguished from the earlier Middle Stone Age as the time in which modern human behavior developed in Africa. This definition has become more tenuous as evidence for such modern human behaviors is found in sites which predate the LSA significantly.
The LSA follows the Middle Stone Age and begins about 50,000 years ago. The LSA is characterized by a wider variety in stone artifacts than in the previous MSA period. These artifacts vary with time and location, unlike Middle Stone Age technology which appeared to have been relatively unchanged for several hundreds of thousands of years. LSA technology is also characterized by the use of bone tools. The LSA was associated with modern human behavior, but this view was modified after discoveries in MSA sites such as Blombos Cave and Pinnacle Point.