## 2 Related Work  
Non-verbal communication is defined as the behavior of the face, body, or voice, without linguistic content, i.e., everything except words [22]. Non-verbal communication involves, for example, facial expressions, gestures, voice tonalities, and speaking time, among many others. The work of [15] approaches the assessment of non-verbal collaboration, but just considering non-verbal elements of spoken interactions. Despite this limitation, this work serves as an initial foundation for our proposal, which aims to extend its spoken interaction-based approach to body posture analysis. This section considers works regarding using body posture and time in collaborative contexts. Postures may provide information related to the sentiments and intentions of a person or indicate power and social status [23]. For instance, the respect and disposition towards the participants during the interaction may be identified by the individual's posture [23]. In this sense, a closed and inflexible posture is less attractive than an open and relaxed posture. Identifying postures during collaboration may be important complementary information about the participants and may help to better understand the entire learning process [24]. [PERSON] et al. [25] investigated how posture influences the generation of novel ideas in the context of creativity by proposing two studies. The first study used a sample of 102 students divided into two balanced groups. Each subgroup completed one of two creative tasks, and they requested the students to adopt randomly open and closed postures while describing their ideas. The findings support the hypothesis that posture influences creative task performance but did not conclude that open postures facilitating effects are specific to creativity. The second study involved 20 students, and they added additional dimensions to the analysis, incorporating different physiological measures and a logical task not requiring creativity. The results showed that postures specifically influence the performance of creative tasks. [PERSON] et al. [26] incorporate the component of emotions in the participants. The method is very similar to that proposed by [PERSON] et al., but here the emotions are induced by watching videos, and the participants are standing. The authors show that participants exhibited the greatest associative flexibility in the open-positive posture and the greatest persistence in the closed-negative posture. These findings show that compatibility between body posture and emotion is beneficial for creativity. This work makes us reflect on how an individual's posture might influence the ability to solve collaborative problems with a creative component or how it can affect the creativity of other team members. Moreover, [PERSON] et al. [27] investigate how the behavior of visible leaders empowers women in leadership tasks. They hypothesize that women tend to imitate the empowered posture of successful women. Experiments showed that, in groups, women adopted the postures of the female leaders when these were famous models (but not when women were exposed to non-famous models). The above suggests that finding mimicry between postures may be a reflection of leadership among interlocutors. From the MMLA perspective, understanding collaboration and communication among students has been studied from different points of view. [PERSON] et al. [28] developed a framework to capture multimodal data (video, audio, clickstream) from pairs of programmers while they were working together to solve a problem in order to predict their level of collaboration. [PERSON] et al. [29] studied how delivering feedback to students regarding collaboration can affect productive small learning group interactions. This feedback can be by a traditional method (verbally delivered interventions) or multimodal (real-time). One of their findings is that simple verbal interventions can help participants pay attention to specific aspects (e.g., how much they talk and how much space they provide to their partner).