Abstract: Experimental study is a fundamental method in lithic analysis to understand the strategy behind exploitation of raw materials, technological process, and past lithic functions. It is particularly useful to conduct experiments with raw materials from the cultural strata and neighboring areas of the archaeological site. In this paper, replication and use experiments of choppers were done at the Yuzui Paleolithic Locality 2 during the excavation season. In terms of replication we made 100 choppers from local gravels (from the cultural strata N=50; and from nearby site surfaces N=50). Then, we using the replicated choppers we cut fresh boughs according to raw material, chopper size and cutting edge angle. We then compared experimental results with artifacts.This work produced several interesting conclusions. First, sandstone was not a useable raw material for chopper manufacture, flint was much better. Interestingly, ancient peoples used more hornfel and quartzite, which were relatively abundant in the local area.Second, our replication experiments suggest that the anvil technique is fairly effective in chopper manufacture，but many site artifacts showed examples of free-hand percussion. The difference in technique probably related to the larger muscle strength of ancient people. Third, the use experiment indicated that there was an optimal axis of force and holding posture ，as well as an optimal length of cutting edge. Examination of archaeological choppers confirmed our observation of this optimal holding posture and cutting edge with the used length of cutting edges usually no more than 6 centimeters.
Based on this research, we further discuss the meaning of so-called chopper tradition and the functional interpretations of choppers. As a type of expedient tool, the chopper is characterized by a form of simple technology. As shown at the Yuzui Paleolithic Locality 2, free-hand percussion was used rather than anvil technique. The priority in ease in acquiring raw materials indicated that choppers were not a type of tool with a long use life. At same time, this tool had an limited temporal and spatial distribution from the earliest Paleolithic into the late Neolithic. Because of this distribution, we do not believe that it can be called a lithic tradition. Its dominance in south China and southeast Asia was very likely associated with rich resources of organic tools such as bamboo, hard wood and bone, as Pope argued. Other lithic tools were replaced by these organic tools as they were not preserved in the sites, which then led to chopper-dominated lithic assemblages.

Key words: Lithics; Chopper tradition; Yuzui Locality 2; Experiment