Factors that influence accuracy

Page 1

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 events

1 slide was different

Participants asked to identify person

Group 1 - Person gets a cheque out

Group 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 = Age

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

Each

Each group watched same video of a kidnapping

Asked 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