The rapid increase in smartphone surveys and technological developments open novel opportunities for collecting survey answers. One of these opportunities is the use of open-ended questions with requests for oral instead of written answers, which may facilitate the answer process and result in more in-depth and unfiltered information. Whereas it is now possible to collect oral answers on smartphones, we still lack studies on the impact of this novel answer format on the characteristics of respondents' answers. In this study, we compare the linguistic and content characteristics of written versus oral answers to political attitude questions. For this purpose, we conducted an experiment in a smartphone survey (N = 2402) and randomly assigned respondents to an answer format (written or oral). Oral answers were collected via the open source ‘SurveyVoice (SVoice)’ tool, whereas written answers were typed in via the smartphone keypad. Applying length analysis, lexical structure analysis, sentiment analysis and structural topic models, our results reveal that written and oral answers differ substantially from each other in terms of lengths, structures, sentiments and topics. We find evidence that written answers are characterized by an intentional and conscious answering, whereas oral answers are characterized by an intuitive and spontaneous answering.
