Factors affecting an individual’s ability to identify people aurally are of forensic importance.This paper investigates how topic, dialect, gender, age, and hearing statusaffect detection of an imitated voice. Two imitations of the same person, but ondifferent topics, were used as familiarization voices. One topic was associated withthis person, and the other was not. Using discrimination sensitivity (d-prime) it wasfound that topic had a significant impact on d’, as did age (but only when the topicwas not associated with the imitated person). Dialect, gender and hearing statuswere not significant. The older group of listeners was less convinced by the imitationsand in particular the one not associated with the person being imitated. These resultsimply that the validity of earwitness evidence is negatively affected by age and topic.