@Xibanya 1st instance I can find is 2010 paper. Of course common usage differs.
"Importantly then, costly signalling holds that both the conservation of
religion and its apparent irrationality can be accounted for by a single
model, one that combines moral policing with virtue signalling."
Religious culture and cooperative prediction under risk: Perspectives from social neuroscience
J Bulbulia, U Schjoedt