Factors affecting the accuracy of eyewitness testimony: misleading information, including leading questions and post-event discussion; anxiety.

What is Misleading Information?

• Incorrect information given after an event.
• Distorts memory of original event.

What is a Leading Question?

• Question that suggests a desired answer.
• Can distort eyewitness recall.

Loftus and Palmer — Aim

• Investigated whether leading questions affect eyewitness testimony.
• Studied whether wording of questions changes speed estimates.

Loftus and Palmer — Procedure

• 45 students watched 7 film clips of car accidents.
• Participants estimated speed of cars after each clip.
• Asked: “About how fast were the cars going when they ____ into each other?”
• Different verbs used included:     * smashed     * collided     * bumped     * hit     * contacted.

Loftus and Palmer — Findings

• “Smashed” produced highest speed estimates.
• “Contacted” produced lowest speed estimates.
• Mean estimate for “smashed” was around 40.8 mph.
• Mean estimate for “contacted” was around 31.8 mph.
• Leading questions distorted eyewitness recall.

Loftus and Palmer — Second Study Procedure

• 150 participants watched a car accident film.
• Asked speed question using either:     * smashed     * hit     * no verb/control group
• One week later participants asked if they saw broken glass.

Loftus and Palmer — Second Study Findings

• Participants in “smashed” condition most likely to report broken glass.
• No broken glass was actually present.
• Supports substitution explanation because memory was altered.

What is Response Bias Explanation?

• Wording of question influences participant response.
• Memory itself is not changed.

What is Substitution Explanation?

• Leading question changes memory of the event itself.

What is Post-Event Discussion (PED)?

• Discussion with others after witnessing an event.
• Can distort memory recall.

What is Memory Conformity?

• Witness changes memory to match another person’s account.

What is Informational Social Influence in PED?

• Witness assumes other people are correct.
• Changes memory to be more accurate.

What is Normative Social Influence in PED?

• Witness agrees with others to avoid conflict or fit in.

Gabbert et al. — Procedure

• Participants watched different versions of same crime.
• Discussed event together afterwards.

Gabbert et al. — Findings

• Participants often included details gained from other witnesses.
• Supports effects of post-event discussion.

What is Anxiety in EWT?

• Emotional arousal experienced during witnessing an event.
• Can affect accuracy of recall.

What is Weapon Focus?

• Attention focused on weapon reduces recall of other details.

Johnson and Scott — Procedure

• Participants overheard argument.
• Saw either man carrying pen or bloody knife.

Johnson and Scott — Findings

• Recall poorer in knife condition.
• Supports weapon focus effect.

What is the Easterbrook Hypothesis?

• Anxiety narrows attention.
• Focus placed on central detail while peripheral details forgotten.

Yuille and Cutshall — Procedure

• Interviewed real witnesses of a shooting in Canada.

Yuille and Cutshall — Findings

• Witness recall remained highly accurate months later.
• Suggests anxiety may improve recall in real situations.

What is the Yerkes-Dodson Law?

• Moderate anxiety produces highest performance and recall.
• Very low or very high anxiety reduces accuracy.
• Shown as an inverted U-shaped relationship.

EWT Evaluation — Real World Application

• Research used in police interviews and legal system.
• Helps improve eyewitness procedures.

EWT Evaluation — Artificial Research

• Many studies use lab experiments and videos.
• May lack emotional realism of real crimes.

EWT Evaluation — Supporting Research for PED

• Gabbert et al. supports memory conformity and effects of PED.

EWT Evaluation — Anxiety Findings Are Mixed

• Some studies show anxiety harms recall while others show it improves recall.
• Relationship between anxiety and EWT may not be straightforward.