Ninety-six elementary-school children and 96 college students viewed a slide sequence of a crime, followed by target-present or target-absent photo identification in sequentially or simultaneously presented lineups. Prior to photo identification, half the subjects received a practice lineup. Children had a higher rate of choosing than adults, resulting in more foil identification errors in both target- present and target-absent lineups. Without prior practice, sequential presentation as compared to simultaneous presentation reduced errors in target-absent lineups for adult witnesses and showed a similar but nonsignificant reduction for child witnesses. With prior practice, sequential presentation lost the advantage over simultaneous presentation in target-absent error reduction. Practice reduced target-absent errors in simultaneous-presentation lineups for both age groups. The author notes that the results of the present study, where witnesses were briefly exposed to a stranger rather than to a familiar adult for an extended time period, are more relevant to identification of a criminal in a robbery situation than to a child abuse situation. 2 tables and 28 references