Estimator Variables
Definition
Factors present at the time of the crime that affect encoding accuracy but cannot be retrospectively controlled, including weapon focus, cross-race effect, lighting, and retention interval.
- Field
- Eyewitness memory research
- Controllable after the fact
- No, fixed at time of the crime
- Examples
- Weapon focus, cross-race effect, lighting, retention interval
- Contrasted with
- System variables, which investigators can control
Common questions
How do estimator variables differ from system variables in eyewitness research?+
Estimator variables are fixed at the moment of the crime and cannot be changed afterward, such as lighting or stress level, while system variables are procedural choices investigators make later, such as lineup instructions or presentation method, which can be reformed to reduce error.
Why does weapon focus reduce eyewitness accuracy?+
Attention narrows onto a visible weapon during a threatening encounter, drawing cognitive resources away from encoding the perpetrator's face, which later weakens the witness's ability to identify the person accurately.
Can estimator variables be used to challenge an identification in court?+
Yes. Because they cannot be fixed after the fact, experts often testify about estimator variables present in a case, such as poor lighting or a long retention interval, to help a jury weigh how much confidence an identification deserves.
Related terms
- Cross-Race Effect
- The empirical finding that own-race identifications are more accurate than cross-race identifications (Meissner and Brigham meta-analysis, 2001), with practical implications for lineup...
- Misinformation Effect
- The incorporation of misleading post-event information into the original memory trace, documented by Loftus and Palmer (1974) and subsequent studies. Distinguished from...
- Post-Identification Feedback Effect
- The inflation of witness confidence, perceived viewing quality, and retrospective memory detail following confirming feedback from an investigator. Documented by Wells and...
- R V. Turnbull Warning
- A mandatory judicial warning in English and Welsh Crown Court proceedings when the case depends substantially on identification evidence, requiring the jury...
- Reconstructive Memory
- The psychological model of memory as a constructive process shaped by schemas, expectations, and post-event information, rather than a fixed recording. Foundational...
- System Variables
- Factors in the identification process that are within the control of the criminal justice system, including lineup administration, instructions, and feedback policies....
- Weapon Focus Effect
- The reduced encoding of a perpetrator's face when a weapon is present, attributable to attentional narrowing toward the threat-relevant stimulus (Steblay meta-analysis,...