Valid emotion-induction clips must be short, single-topic, and shown only once.

Evidence

In the second phase, participants viewed a documentary film clip (Summers, 2008) that focused on a Muslim woman who was the victim of a bomb attack. This film clip met Rottenberg et al.’s (2007) recommendations for film clip usage in emotion research by being homogenous in content (specific focus of the film was on a Muslim woman), free of carryover effects (no other film clips were shown), and long enough to increase signal boost, yet decreasing the effects of habituation, sensitization, and fatigue (the film clip was 72 s long). — Sherman A. Lee, Chelsea A. Reid, Stephen D. Short, Jeffrey A. Gibbons, Ruth Yeh, and Matthew L. Campbell, Fear of Muslims, 124

Categorization

• XREF: Connects to broader media-effects and emotion-induction methodology literature on stimulus selection and habituation.
• SHARE: The 72-second rule for emotion-induction film clips is exactly the kind of methodological trivia a psych-methods friend would enjoy.