In Study 1, 193 children, half in New York City and half in Recife, Brazil, heard hypothetical dilemmas about whether to keep a promise or tell the truth. An adult interviewer suggested the alternative to the child's initial choice. Younger children (5 to 8 year olds) were more suggestible than older children (10 to 12 year olds), US more than Brazilian children; and suggestibility occurred more frequently from promise to truth than vice versa. In Study 2, children in each country were interviewed either by an older adult or by a ‘teenager’. Suggestibility was greater when the interviewer was an adult than a teenager in the US, but not in Brazil. Findings are discussed in terms of developmental trajectories, from heteronomy to autonomy, and authority relations within cultures. Copyright © 2004 John Wiley & Sons, Ltd.