Factors that influence accuracy

Improves Recall

Impairs Recall

Yerkes-Dodson Law

Christianson & Hubinette (1993)Found that when they questioned 58 real witnesses who had been threatened (high anxiety) they were more accurate in recall than onlookers (low anxiety)

Deffenbacher et al (2004)Meta-analysis showed anxiety decreases recall

Accuracy is better under moderate arousal

LOFT

LOFTUS 1979

2 

2 Groups of students watched a slideshow of events1 slide was differentParticipants asked to identify person

Group 1 - Person gets a cheque outGroup 2 - Person gets a gun out

FINDINGS

- Participants in group 1 were 39% accurate- Participants in group 2 were 11% accurate

Average fixation time- Gun - 3.72 secs- Cheque - 2.44 secs

WEAPON DISTRACTED ATTENTION FROM MAN

Valentine & Coxon

Effec

Effect of leading questions on different age groups

Quasi Experiment

3 groups compared - Children, Young Adults, Elderly

IV = AgeDV = Accuracy of EWT in response to leading & non-leading questions

Each 

Each group watched same video of a kidnappingAsked a series of leading & non-leading questions

FINDINGS- Children mislead more by leading questions- Elderly & Children gave more incorrect answers to non-leading questions

CONCLUSION - Age can affect accuracy of EWT

Anastasi & Rhodes

"Peop

"People have better recall of people their own age" - Could be a problem - Studies use images of similar ages

- Participants from different age groups rated 48 photos for attractiveness. - Then shown another 48 (24 the same) - Who had they seen before? 

FINDINGS- Young and Middle Aged (18-25 & 35-45) more accurate- All age groups more accurate in identifying those from same age group

Effect of Age on Confidence of Witness

Effect of Delay on Accuracy of Young & Older Witnesses

Yarmey- Found no significant difference in accuracy between young & old participants when asked to recall a person they had just spoken to.- Younger + Middle Aged more confident than older.

Memon et al- Found that when delay between incident and recall was short, there is no difference in accuracy of recall between young & old. - When recall is delayed by a week, older recall was worse

High Validity - Can be generalised to similar situations Studies useful for the police

Field experiments - lack of control of variables Lab experiments - low ecological validity Ethical issues - protection from harm/distress

Anxiety

Weapons Focus

Age of Witness

Age & Delay

Evaluation