Assume that Latané and Darley want to demonstrate the external validity of their 1968 experiment on bystander intervention. To do this, they conduct a study in which participants solve crossword puzzles alone, or in large or small groups. While the participants are working on the puzzles, they overhear a woman fall from a ladder and cry out, "Oh, my leg! I can't move it!" The researchers then observe and record the number of participants who attempt to help. The study described here represents a________ of the original "seizure" study.