  We present the results of two studies on how individuals interact with each
other during a international, interdisciplinary scientific conference. We first
show that contact activity is highly variable across the two conferences and
between different socio-demographic groups. However, we found one consistent
phenomenon: Professors connect and interact significantly less than the other
participants. We interpret this effect as non-tenured researchers using
conferences to accumulate social capital, while established researchers already
have such capital. We then show that groups mix well during conferences, but
note that a language-based homophily is always present. Finally, we show that
the dynamics of the contacts across days is also similar between conferences.
First day connections are established, then filtering occurs during the
following days. The connection turnover between consecutive days proves to be
large ($\sim 50 \%$), and related to the intensity of interactions.
