Respondents, who had either seen or not seen a sample of the iconic gestures that encoders produce when narrating a story, answered questions about the original story and it was found that the overall accuracy score for respondents who saw the iconic gestures in addition to hearing the speech was 56.8% compared to 48.6% for speech only. This was a highly reliable effect and suggests that iconic gestures are indeed communicative. Character viewpoint gestures were also significantly more communicative than observer viewpoint gestures particularly about the semantic feature relative position , but the observer viewpoint gestures were effective at communicating information, particularly about the semantic features speed and shape . There were no significant correlations between the amount of information that gestures added to speech and the amount they conveyed in its absence, which suggests that the relationship between speech and gesture is not fixed but variable. The implications of this research for our fundamental conception of iconic gestures are considered.