A multinomial model for lineups – request for extension

• Applicant: Professor Dr. Axel Buchner
• Subject Area: General, Cognitive and Mathematical Psychology
• Term: since 2021
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 456214986

The aim of the first project phase was to validate the newly developed multinomial model for lineups (from now on: 2HT-EIM for two-high threshold eyewitness identification model). The 2HT-EIM contains four parameters that are estimated on the basis of judgments in lineups: one parameter for the detection of the presence of the perpetrator (dP) in the lineup and one for the detection of the absence of the perpetrator (dA), one parameter for the selection of ‘conspicuous’ perpetrators or wrongly suspected persons in unfair lineups (b for biased selection) and one parameter for choices based on guessing processes (g for guessing-based selection). To date, four online validation experiments from the project proposal have been conducted and published (Winter, Menne, Bell & Buchner, 2022). Also, eight published datasets have been reanalyzed for validation purposes and the analyses have been published (Menne, Winter, Bell & Buchner, 2022b). In addition, four more online experiments have been conducted using the morphing manipulation suggested in the project proposal to generate unfair lineups. The manuscript documenting these four experiments has been submitted for publication (Menne, Winter, Bell & Buchner, 2022a).Following the successful validation of the 2HT-EIM in the first phase of the project (Menne et al., 2022b; Winter et al., 2022), the model shall now be used to answer new scientific questions for which it is so far unclear what processes underlie the effects on observable behavior. Specifically, there are four goals for this endeavor. The first goal is to answer the question of how context reinstatement with multiple suspects in lineups affects the detection and guessing processes underlying observable judgments. The second goal is to answer the question of how practice lineups affect the detection and guessing processes. The third goal is to answer the question of how stimulating memory-related metacognitions affects detection and guessing processes. Finally, the fourth goal is to answer the question of what effects the position of a suspect in a lineup has on detection and guessing processes. Two experiments are planned for each of these four goals.

• DFG Programme: Research Grants
• Co-Investigator: Dr. Raoul Bell