Interviewing children and adults: The effect of question format on the tendency to speculate

In formal interviews it is important that interviewees indicate when they d o not know the answer, rather than speculate. In this study we investigated whether question format affected the tendency to speculate. One hundred an d twenty-eight 5- to 9-year-olds, and 23 adults, were told two short storie s, and were then asked questions about the stories, Half of the questions w ere answerable based on the information provided; the other half were not a nswerable. Within these categories, half of the questions were closed quest ions (i.e. only required a yes/no response), and half were wh-questions (i. e. requested particular details to be provided). All participants performed at ceiling with the answerable questions. With the unanswerable questions, there was an effect of format. The majority of children and adults correct ly indicated that they did not know the answer when asked unanswerable wh-q uestions. However, the majority of children, and just over one-fifth of adu lts, provided a response (i.e. 'yes' or 'no') to the closed unanswerable qu estions. The implications for interviews, particularly within a forensic co ntext, are discussed. Copyright (C) 2001 John Wiley & Sons, Ltd.