Background to the study

In real-life crimes, victims often experience high levels of fear, which differs from the calm conditions in many lab experiments. For ethical reasons, researchers cannot deliberately cause extreme stress in participants, but understanding its impact is essential. This study aimed to explore how anxiety in a realistic, everyday setting might reduce the accuracy of eyewitness recall, bridging the gap between artificial experiments and real-world experiences.

Aims of the study

The primary aim was to investigate whether placing participants in an anxiety-inducing situation would lead to increased stress levels, and if this stress would impair their ability to recall details accurately. Specifically, the researchers wanted to test eyewitness memory in a scenario that involved personal threat, without participants knowing in advance that their memory would be assessed.

Participants

The study involved 56 volunteers, consisting of 29 females and 27 males, with an average age of 31 years. Participants were recruited at the London Dungeon, a tourist attraction, and offered a reduced admission price in exchange for completing questionnaires.

Procedure

Key steps in the procedure:

1. Informed consent and baseline measurement - Participants gave informed consent upon arrival. Their average baseline heart rate was measured immediately.
2. Anxiety induction in the labyrinth - Participants entered the Horror Labyrinth, a dark maze with mirrored walls and Gothic features intended to disorient visitors. An actor, dressed in a dark robe with pale, wounded-looking make-up (referred to as the 'scary person'), stepped out to block each participant's path. The actor was alerted to target specific participants, ensuring an encounter during their approximately seven-minute slow walk through the crowded labyrinth. Heart rate was measured again during this phase to capture changes due to the experience.
3. Anxiety questionnaires (about 45 minutes later) - Participants completed a state anxiety questionnaire with 20 statements (e.g., 'I was tense' or 'I felt frightened'), rated on a scale to indicate how they felt in the labyrinth. They then filled out a trait anxiety questionnaire with 20 statements (e.g., 'I feel nervous and restless' or 'I have disturbing thoughts'), rated to describe their general feelings.
4. Memory recall tasks - Participants answered questions about the 'scary person', including free recall (open-ended descriptions) and cued recall (specific prompts like age, height, or clothing).
5. Identification and confidence rating - Finally, participants viewed a nine-person photograph line-up, with the 'scary person' randomly placed among them. They selected a photo and rated their confidence in the choice on a scale of 0 to 100 per cent.

Heart rate changes were correlated with state anxiety scores.

Results

Key findings:

• Heart rate changes - The average baseline heart rate was 74.7 beats per minute (bpm), increasing to 86.9 bpm in the labyrinth.
• Anxiety levels by gender - Females reported higher state anxiety (mean score of 52.8) than males (45.3). There was no gender difference in trait anxiety, with an overall mean of 36.8 (males: 36.3; females: 37.3).
• Impact on recall accuracy - Participants with lower state anxiety were more accurate in recalling details about the 'scary person'. Conversely, higher state anxiety was linked to reduced accuracy. Males were generally more accurate than females in recall tasks.
• Identification and confidence - Those who correctly identified the 'scary person' from the line-up expressed higher confidence in their choice.

Conclusions and implications

The study concluded that physiological arousal, such as an elevated heart rate, is strongly associated with subjective feelings of anxiety. Females experienced higher state anxiety in the anxiety-inducing situation compared to males, suggesting that gender and emotional state should be considered when evaluating witness testimony.