Not by signalling alone: Music's mosaicism undermines the search for a proper function.

Mehr et al. seek to explain music's evolution in terms of a unitary proper function - signalling cooperative intent - which they cash out in two guises, coalition signalling and (allo)parental attention signalling. Although we recognize the role signalling almost certainly played in the evolution of music, we reject "ultimate" causal explanations which focus on a unidirectional, narrow range of causal factors.