Before revision:  By looking for heuristics that depend upon knowledge of group-level facts , we can back-infer the types of knowledge individuals possess . Summary measures  then place groups within a taxonomy, providing a  "social assay" of group-level knowledge.
After revision:  By looking for heuristics that depend upon knowledge of group-level facts , we can back-infer the types of knowledge individuals possess . Summary measures of these heuristics then place groups within a taxonomy, providing a "social assay" of group-level knowledge.