Delays reduce culprit-presence detection but do not affect guessing-based selection in response to lineups

Area of Science:

• Cognitive Psychology
• Forensic Science
• Eyewitness Identification

Background:

• Police lineups are crucial for eyewitness identification but are often conducted after varying delays.
• Crime-to-lineup delays may negatively impact the accuracy of identifying both the presence and absence of a suspect.
• Such delays could potentially influence eyewitnesses to resort to guessing when making selections.

Purpose of the Study:

• To investigate the impact of different crime-to-lineup delays on eyewitness identification accuracy.
• To examine how detection of culprit presence and guessing-based selection change over time.
• To determine the optimal timing for conducting police lineups to maximize memory-based detection.

Main Methods:

• Participants viewed a staged crime video.
• They subsequently completed simultaneous photo lineups after immediate, one-day, one-week, or one-month delays.
• Data on culprit-presence detection and guessing-based selection were analyzed across delay conditions.

Main Results:

• A significant decrease in the probability of detecting the culprit's presence was observed as delay increased.
• This decline followed a power function, with the most rapid decrease occurring at shorter delays.
• The probability of guessing-based selection remained constant across all delay intervals.

Conclusions:

• The accuracy of eyewitness identification significantly diminishes with increasing crime-to-lineup delays.
• Eyewitnesses do not compensate for reduced detection accuracy by increasing their guessing rate.
• Conducting police lineups as soon as possible after a crime is critical for maximizing accurate, memory-based culprit detection.