Prehistoric stone tool knapping was an expert skill. This experiment was a cognitively demanding test of modern day knappers using an adaptation of the classic Chase and Simon paradigm from chess expertise (where chess experts/novices are briefly exposed to chess positions and later asked to recall the patterns). Here, pieces of flint debitage were used instead of chess pieces, and it was a recognition test rather than recall. Expertise was measured by social status and questionnaire. Three participant groups were tested (archaeology professionals, students, and nonexperts) in 15 trials each, each comprising four tasks: (1) sorting task, (2) exposure, (3) sorting task, and (4) recognition task. The sorting task (interference) required participants to sort flint debitage by size into different buckets. In the exposure task, the experimenter showed the participant three types of rock (flakes, miscellaneous rocks, cores) seriatim for 2 seconds each. The recognition task required that the participant attempt to identify previously seen rocks on three tables (flakes, miscellaneous, and cores tables). Experts performed significantly better than students and non-experts. Post-session interviews revealed a diversity of strategies, suggesting that increased expertise enhanced perception. This result parallels chess expert studies, and template theory in chess might apply to knappers.