## 2 Theoretical Background
### Deception in Computer-Mediated Communication (CMC)  
Deception happens every day and in all forms of interaction, through face-to-face communication or through certain media such as mobile phones, computers, television, etc. A common assumption is that detecting deception in face-to-face interaction is an easier task given that a person has much more information at their disposal, unlike verbal \"online\" communication, which lacks non-verbal signs such as gestures, body posture, facial expressions, etc. In addition, as mentioned in previous research in asynchronous computer-mediated communication, the sender has more time, which makes it \"easier for senders to construct and/or harder for receivers to detect relative to face to-face interactions\" [3]. Nevertheless, in a study conducted on a group of people who participated in face-to-face interactions and computer-mediated communication, it was determined that human performance in detecting deception in computer-mediated communication exceeded that in face-to-face interaction and that the truth bias and deception rate in both cases did not differentiate [11]. However, human prediction accuracy still did not exceed chance. [PERSON] and colleagues [2] believe that the sender in CMC distances himself from the message that \"reduces their accountability and responsibility for what they say, and an indication of negative feelings associated with the act of deceiving\". Likewise, one of the important indicators of why people are better at detecting deception via computers is precisely the fact that they lack certain information about the other person, so they are much more suspicious and will suspect deception sooner. Research in CMC examines the influence of Linguistic Style Matching (LSM) and Interpersonal Deception Theory (IDT) on the linguistic characteristics of conversations during honest and fake conversations [2; 12]. The LSM theory explains how people in a conversation adapt each other's linguistic style to match their partner's. According to the LSM theory, deception in a conversation can be detected by analyzing the verbal characteristics of the interlocutor (who is unaware of the deception) and not exclusively those of the speaker (who is lying) given that their linguistic styles match [12]. In the study conducted during synchronous computer-mediated communication, correlation was recorded in the linguistic style of the interlocutors. More precisely, the correlation was achieved when using first, second, and third person pronouns and negative emotions. An interesting conclusion was that the linguistic profiles of both interlocutors coincided to a greater extent during false communication compared to true communication, especially in a case when the speaker was motivated to lie [12]. There is a possibility that speakers deliberately use LSM when trying to deceive in order to appear more credible to the partner, which is what the IDT theory deals with. IDT studies the context of the speaker (who is lying) and the interlocutor (who is not aware of the deception) and the changes in their linguistic styles through honest or false communication, with the difference that it understands these changes as strategic behavior that the speaker uses to facilitate the deception process [13]. \"Deceivers will display strategic modifications of behavior in response to a receiver's suspicions, but may also display non-strategic (inadvertent) behavior, or leakage cues, indicating that deception is occurring \" [2]. On the other hand, interlocutors in the case of non-strategic behavior may become suspicious and ask more questions, thus forcing the speaker to change his linguistic style and adapt to the interlocutor. So far, the best known method of detecting deception precisely is the use of a polygraph, which provides insight into a series of autonomous and somatic psycho-physiological activities that are invisible to the human eye, but which strongly signal deception.