  First contact with another civilization, or simply another intelligence of
some kind, will likely be quite different depending on whether that
intelligence is more or less advanced than ourselves. If we assume that the
lifetime distribution of intelligences follows an approximately exponential
distribution, one might naively assume that the pile-up of short-lived entities
dominates any detection or contact scenario. However, it is argued here that
the probability of contact is proportional to the age of said intelligence (or
possibly stronger), which introduces a selection effect. We demonstrate that
detected intelligences will have a mean age twice that of the underlying
(detected + undetected) population, using the exponential model. We find that
our first contact will most likely be with an older intelligence, provided that
the maximum allowed mean lifetime of the intelligence population, $\tau_{\rm
max}$, is $>e$ times larger than our own. Older intelligences may be rare but
they disproportionality contribute to first contacts, introducing what we call
a 'contact inequality', analogous to wealth inequality. This reasoning
formalizes intuitional arguments and highlights that first contact would likely
be one-sided, with ramifications for how we approach SETI.
