Science Buddies: "Ask an Expert"

Hi,
I am doing the project on Testing for Bias in a Photo Lineup and I am confused as to how the procedure relates to a real suspect lineup. When a real lineup is conducted, instead of viewing a description, a witness would actually see the suspect. Why wouldn't a mock witness in this project do the same as a real one?

Hi,

I read through the description of the project, and your witnesses will be seeing the actual photo of the suspect as well as a few additional photos. In a real crime, a witness would see the suspect, and then be interviewed by police about what the subject looked like. In your project, this would be like the description that the "witness" will write down after looking at a photo. The police would then use this description (i.e. male, brown hair, tall) to hopefully identify the suspect. At the lineup, the witness would see multiple people, including the suspect, all of whom ideally should fit the general description initially provided by the witness. So in the case of your experiment, after the witness has seen a photo and given a fairly general description, you would go through your photos and pick 5 additional photos that fit this very general description. Then you would present these 6 photos to the witness and ask them to identify the suspect they saw before. You wouldn't want your lineup to be all girls with the only male the suspect, because than it is obvious which one the witness saw before. Similarly, if the witness described a suspect with blonde hair, but you only choose pictures of people with brown hair, then the "suspect" is obvious.

This experiment actually does a fairly good job relating to a real suspect lineup.

I hope this helps, and please feel free to post again here if you have more questions!
JMP