## 2 Materials and Methods  
### Dataset  
In our study, we used statements from a project on deception detection with 400 participants aged 18-60 (F = 226; Mage = 30.58, SD = 9.63). Overall, 4.5 percent of the subjects completed primary school, 46.5 percent had secondary education, and 49 percent had higher education. The native language of all respondents was Polish. The subjects were recruited using social media and internet advertising portals. We excluded all volunteers with psychological education and those who had any experience/training in detecting lying. Each participant was first asked to complete a short questionnaire. Based on its results, we determined which of two polarizing topics the respondent has a clearly defined position on. Topics included various social, political, economic, and sports issues (full list in Table 1). They were then asked to generate four statements. Two of them (focused on one topic) were expressed in spoken communication and recorded, and the other two were typed in an internet chat window. One statement on a particular topic was always consistent with the participant's real position, whereas the other presented an opposing viewpoint. In the case of written statements, the respondents were asked to spend at least 5 min, and in the case of oral statements, 2 min, to generate the statement. The maximum time for speaking/writing was not limited.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline  & \multicolumn{2}{c}{**Written**} & \multicolumn{2}{c}{**Transcriptions**} \\ \hline
**Topic** & **N** & **\%** & **N** & **\%** \\ \hline Vaccinations should/ should not be compulsory & 134 & 17.6 & 92 & 12.5 \\ \hline Polish energy should be based mainly on coal/ renewable and non-emission sources & 81 & 10.6 & 55 & 7.4 \\ \hline People should/should not eat meat & 76 & 10 & 78 & 10.6 \\ \hline Smartphones and social media positively/negatively affect interpersonal relationships & 54 & 7.1 & 55 & 7.4 \\ \hline Abortion should/ should not be legal & 91 & 11.9 & 94 & 12.7 \\ \hline [PERSON] exists/does not exist & 43 & 5.6 & 50 & 6.8 \\ \hline [PERSON] is/is not the best Polish football player & 60 & 7.9 & 53 & 7.2 \\ \hline [PERSON]’s treatments are/are not effective and help people heal/can harm the sick & 30 & 3.9 & 50 & 6.8 \\ \hline Poland should/should not accept more immigrants than today & 62 & 8.1 & 40 & 5.4 \\ \hline GM food is/is not safe and useful, and we should/should not invest in these kinds of crops & 34 & 4.5 & 34 & 4.6 \\ \hline The political situation in Poland is going in the right/wrong direction & 32 & 4.2 & 54 & 7.3 \\ \hline In general, most people can/cannot be trusted & 32 & 4.2 & 50 & 6.8 \\ \hline [PERSON] is/is not the most effective personal trainer in Poland & 30 & 3.9 & 31 & 4.2 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Number of statements by topic.  
We gathered 1600 statements (utterances) in total, four from each participant: two real ones (one typed and one spoken) and two false ones (one typed and one spoken). Participants were asked several standardized questions while giving statements so that each one contained the same elements, such as their stance, arguments for that position, and summary. Several statements were not registered due to technical reasons, and after rejecting statements from participants who did not understand the instructions or were not Polish, we finally obtained 757 typed utterances and 730 spoken and transcribed ones.