The eyes are of utmost importance in our daily life. Not only do they serve the purpose of constantly gathering information about the environment but where we direct our gaze also has a strong signalling function in social situations. With continued population growth and people living closer and closer together in cities, social situations characterized by a shortage of personal space a are a daily phenomenon for most human beings. In such situations, non verbal behavior including where we allocate our attention is how we generally communicate with others.
We hypothesized that social attention would be modulated by different communication roles and the amount of people present. Since there are currently hardly any ecologically valid methods to explore social attention in naturalistic social situations we conducted an experiment and had n=37 subjects (female=25, age=22.240.23) individually seated in a dyadic (1 person sitting close) social setting and a group (4 persons sitting close) social setting while assessing their gazing behavior with a mobile eye-tracking device. We devided the social interaction in a phase where people would sit quitely together and a communication phase where people would speak to each other about every day topics. Participants role in a social interaction as well as whether they were interacting with one or four persons strongly affected their gaze patterns. We found that irrespective of crowding, participants showed more social attention when engaged in an active communication compared to when sitting silently. When sitting silently, particpants devoted more of their attention towards other people when being in a group with four others than in a dyadic situation with only one person close by. Furthermore, while communicating, participants showed more social attention while listening to others speak compared to when actively speaking themselves. Participants also showed more social attention when interacting with one person compared to when interacting with four others. The strong signal function of gaze behavior can explain why more social attention is generally devoted to others while also conversing with them compared to while merely sitting silently close to them. Assuming there is an optimal or appropriate amount of social attention to be displayed during a conversation, the demands for this amount of attention to be met are a lot higher in a dyadic compared to a conversation with four other people, explaining the difference in social attention while conversing in the two crowding dimensions. Since sitting silently in close proximity to others can be a very ambigous situation, it is likely that people needed to gather more important social signals in a higher crowded situation with more people present compared to the same situation with only one person, in order to reduce ambiguity by “scanning” the intentions of others. The fact that participants show more social attention while listening compared to when speaking during a conversation is explainable by the additional cognitive load that occurs while under the eye contact of others, which has been shown to interfere with verb generation. Furthermore, watching someones lips can help decode verbal information.
The results enlighten the complex nature of how overt visual attention operates in a naturalistic social setting. This study also highlights the fruitful application of mobile eye-tracking as a promising methodical approach for future research on attention in real world settings.