The impact of multiple show-ups on eyewitness decision-making and innocence risk
If an eyewitness rejects a show-up, police may respond by finding a new suspect and conducting a second show-up with the same eyewitness. Police may continue finding suspects and conducting show-ups until the eyewitness makes an identification (Study 1). Relatively low criterion-setting eyewitnesses filter themselves out of the multiple show-ups procedure by choosing the first suspect with whom they are presented (Studies 2 and 3). Accordingly, response bias was more stringent on the second show-up when compared with the first, but became no more stringent with additional show-ups. Despite this stringent shift in response bias, innocence risk increased with additional show-ups, as false alarms cumulate (Studies 2 and 3). Although unbiased show-up instructions decreased innocent suspect identifications, the numbers were still discouraging (Study 4). Given the high number of innocent suspects who would be mistakenly identified through the use of multiple show-up procedures, using such identifications as evidence of guilt is questionable. Although evidence of guilt is limited to identifications from a single show-up, practical constraints might sometimes require police to use additional show-ups. Accordingly, we propose a stronger partition between evidentiary and investigative procedures.
|Keywords||Decision-making, Eyewitness identification, Innocence risk, Police practices, Show-ups|
|Journal||Journal of Experimental Psychology: Applied|
Smith, A, Bertrand, M. (Michelle), Lindsay, R.C.L. (R. C.L.), Kalmet, N. (Natalie), Grossman, D. (Deborah), & Provenzano, D. (Daniel). (2014). The impact of multiple show-ups on eyewitness decision-making and innocence risk. Journal of Experimental Psychology: Applied, 20(3), 247–259. doi:10.1037/xap0000018