Interviewees often face pressure to give an answer to a question even when there isn’t enough information available. It is typical for interviewers to force interviewees to answer questions by rephrasing questions or fishing for guesses. This attitude extends to society at large, where, for many people, saying “I don’t know” is tantamount to saying “I am stupid.”
Recent experiments, however, suggest that the approach of demanding an answer despite a lack of confidence reduces the overall accuracy of responses. Conversely, encouraging interviewees to say “I don’t know” and to elaborate on their doubt leads to richer answers and more meaningful data collection.
In a study of this subject1, 78 undergraduate students were shown a video of a violent burglary and police chase and told they would have to answer questions about it later. After the video, all participants were asked to freely recall what they saw in the video, after which they were required to complete 20 minutes of logic problems to distract them. The participants were then randomly assigned to one of three groups and asked to answer 24 questions about the video they had watched:
- In the “Don’t Know” (DK) group, participants were encouraged to answer “I don’t know,” to any of the questions they were unsure of. If the participants answered “I don’t know” to a question, they were asked to clarify whether they meant “the information might have been present, but I can’t remember” or “the information was not present.”
- In the No DK group, participants were asked not to answer “I don’t know” unless it was absolutely necessary.
- In the No instruction group, participants were instructed to answer the questions, with no directions on answering “I don’t know.”
The results of the study indicated that the participants who were encouraged to answer “I don’t know” gave fewer incorrect answers and just as many correct answers as the other participants. The amount of correct responses given from the group was not lower than others, which indicates that the group did not arbitrarily answer “I don’t know” to avoid answering at all.
The control and no-DK group did not significantly differ, which suggests that people tend not to say “I don’t know” unless they are specifically encouraged to do so, even when the questions are purposefully unanswerable.
A second study was done to test and expand on these findings. A second group of 76 undergraduates were recruited. The design was identical to the first experiment, except that the delay between the video and the questionnaire was changed from 25 minutes to 7 days. The results of this study were similar to the first study, with the DK group performing the best.
One of the most significant aspects of this study was that it showed, when participants were encouraged to clarify what they meant by “I don’t know,” the quality and accuracy of the responses increased.
Interviewers should take these findings into account when conducting interviews. Encouraging people to express uncertainty is a more fruitful and realistic approach to asking questions.
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1. Scoboria, A., & Fisico, S. (2013). Encouraging and clarifying “don’t know” responses enhances interview quality. Journal of Experimental Psychology: Applied, 19(1), 72.