How does the introduction of instant-messaging services affect in-person communication throughout age groups?

In this social report, I will try to explore the behavioral changes that the introduction of mobile instant messenger (MIM) had to face-to-face communication.

Since the introduction and massive success of MIM on smartphones, the amount of impersonal communication through WhatsApp, Facebook Messager & co. far exceeds numbers in the age of SMS texting.

Studies like: Smartphone usage in the 21st century:who is active on WhatsApp? show an exponential growth of MIM such as overall mobile phone usage. Further studies show that communicative behaviour can be used to compensate personal deficiencies. (Why shy people use instant messaging: Loneliness and 

other motives) But do MIM substitute or just complement in-person communication? How do people from different age groups communicate in different situations?

I will explore this through both field research (survey amongst students of the University of St.Gallen) such as desk research (Beyond WhatsApp: Older people and smartphones) The evidence from the survey will further be explored in-depth by the creation of focus groups.