Effects of Lineup Member Similarity on Criterion Placement in Simultaneous and Sequential Lineups Heather D. Flowe E

1. Effects of Lineup Member Similarity on Criterion Placement in Simultaneous and Sequential LineupsHeather D. Flowe & Ebbe B. EbbesenUniversity of California, San Diego

2. Acknowledgments Anneka Besemer Crystal Fecht Marimer Santiago Jinny Burns And a small army of research assistants

3. Mistaken Identification

4. Relative versus Absolute Responding Relative Face that is relatively the most similar to the culprit chosen Absolute Test face is strictly compared to culprit in memory

5. Do previously seen faces affect sequential IDs? Implication of absolute model is that lineup foils will not affect accuracy. Thus, similarity structure of the lineup should have little consequence in ID decisions. However, though direct visual comparisons impeded by sequential procedures, is it possible that meta-comparisons in working are memory made?

6. Effects of Similarity on Positive ID Criterion Placement In the verbal learning literature, similarity of distractors on final recognition task influence criterion placement (Benjamin, 2005; Benjamin & Bawa, 2004).

7. Effects of Similarity on Positive ID Criterion Placement Similarity manipulations and lineup identifications (Clark & Davey, 2005): Target IDs reduced when foil similar to perp is presented before the target (experiment 1) In target removed lineups, both simultaneous and sequential participants shifted their choice to a foil (experiment 1 & 2) Next best alternative chosen at a higher rate in removed lineups if presented later in the sequence (experiment 2)

8. Does foil similarity affect criterion placement in simultaneous and sequential lineups? Does order of the suspect in the lineup affect identifications depending on foil similarity? Experiment 1

9. Does foil similarity affect criterion placement in simultaneous and sequential lineups? Low compared to high similarity foils decrease the judgment standard, thereby increasing overall choice rates and positive identifications of the suspect. Experiment 1

10. Does order of the suspect in the lineup affect identifications depending on foil similarity? If suspect placed late rather than early in the lineup, high similarity lineups will lead to fewer positive IDs of suspect. In low similarity lineups, positive IDs will be greater if suspect is placed late rather than earlier in the sequence. Experiment 1

11. Experiment 1Design and Procedure

12. Experiment 1Face Stimuli

13. ResultsIs accuracy affected by presenting foils? Both hits and false alarms were reduced when foils were introduced, regardless of whether the lineup was presented simultaneously or sequentially.

14. ResultsSuspect Choices In simultaneous lineups, rate of picking target and look-a-like is higher if the foils are low rather than high in similarity. In sequential lineups, rate of picking look-a-like is higher if the foils are low rather than high in similarity.

15. ResultsFoil Choices Rate of picking foils did not differ depending on whether or not they matched the study face. Lineup presentation procedure did not affect rate at which foils were chosen.

16. ResultsLineup Rejections Sequential participants rejected the lineups at a higher rate overall than simultaneous participants. Rejections significantly higher overall for matched compared to random lineups.

17. ResultsOrder Effects Matched lineups: Sequential participants “missed” the target more often when presented late in the sequence (Early M=.48 versus Late M=.36) Random lineups: Suspect choices higher if presented later rather than earlier in the sequence (Early M=.24 versus Late M=.30)

18. Experiment 1Conclusions

19. Future Directions Are sequential witnesses affected by the similarity of the first face to the culprit, or only after several faces in the sequence have been predicted? How similar to the culprit does the innocent suspect have to be in order for the similarity effects to hold? Are the effects we reported stronger if foil-culprit similarity is increased further?

20. Conclusion Simultaneous and sequential witnesses affected by similarity characteristics of the lineup in much the same way. Future work examining lineup member similarity should take into account the position of the suspect in the lineup, as order effects may arise as a result of similarity manipulations.

22. Extras

23. Experiment 2 When the target is removed, how is the distribution of choices affected? Is the most popular foil the same lineup member in both procedures?

24. Experiment 2Predictions When the target is removed, how is the distribution of choices affected? Under the relative judgment model, removing the target should shift choices to the next best lineup member. An absolute model predicts that lineup rejections will increase when the target is removed.

25. Experiment 2Predictions Is the most popular foil the same lineup member in both procedures? If so, suggests that the test faces are considered in a similar manner in simultaneous and sequential lineups.

26. Experiment 2Design and Procedure

27. Experiment 2Design and Procedure

28. Experiment 2Full versus Removed LU Results

29. Experiment 2Ranking Results

30. Experiment 2Conclusion

31. Implications for Lineup Construction How should distractors be selected? Luus and Wells (1991) Matching foils to suspect photo creates lineup in which foils are too similar to the suspect If suspect is guilty, hits will be compromised If suspect is innocent, false alarms elevated However, results inconsistent across studies; most suggest false alarms increase in description matched lineups.

32. Expected Effects of Constructing Lineups Based on Match Photo Strategy on LU Members Feature Distributions

33. Implications for Lineup Construction Results of Experiment 1 might lend some insight: If description matched produce low similarity levels and suspect matched produce high similarity levels, criterion placement lower than in description compared to suspect matched lineups. Hits reduced in suspect matched False alarms increased in description matched