found that selection for more elaborate songs can drive the evolu-
tion of the capacity to learn throughout life (Creanza, Fogarty, &
Feldman, 2016; Robinson, Snyder, & Creanza, 2019). We propose
that this evolutionary paradigm in songbirds –that selection on a
learned trait can drive evolution of the brain –provides a possible
example of the phenomenon depicted in Savage et al. (Fig. 2, left
panel): Musical features can act as an intermediary between social
functions and their neurobiological underpinnings.
Savage et al. describe musicality as a “cognitive toolkit.”How
might the framing of musicality as a set of tools affect our under-
standing of its evolution? Our lab modeled the evolution of bird-
song features as culturally transmitted functional traits, similar to
tools, wherein learners aim to imitate proficient tutors (Hudson &
Creanza, 2021). Like other fitness-altering cultural traits, func-
tional signals based on rhythmicity or pitch modulation could
have gradually become more complex if learners preferentially
choose tutors with complex signals. Over time, the cultural devel-
opment of functional signals could elevate the minimum cogni-
tive baseline to recognize and reproduce these signals, thereby
influencing brain evolution to favor attention to and learning
capacity for these acoustic features. In this context, elements of
musicality might have been under selection for purposes other
than the umbrella explanation of “social bonding.”Savage et al.
describe the neural synchronization between auditory and
motor brain regions during rhythm perception to explain the ori-
gins of dance, but only briefly mention other functions of coordi-
nated behavior. Could rhythmic movement have functioned as a
fitness-enhancing tool? Rhythmicity allows for synchronization
of actions between individuals and for individuals to accurately
predict the actions of others. It is thus conceivable that the devel-
opment of rhythmicity would have facilitated a large repertoire of
coordinated behaviors that could have impacted group survival.
Finally, both target articles discuss the hypothesis that musical-
ity evolved through sexual selection, concluding that it is inade-
quate to explain the evolution of musicality. However, this
hypothesis is framed from an intraspecific mate selection perspec-
tive, where females choose males with the most attractive musical
displays. Studying the evolution of birdsong and its role in species
recognition suggests another perspective: in our evolutionary past,
could musicality have served an interspecific function, mediating
the interactions between the ancestors of Homo sapiens and other
hominin lineages? Although musicality appears to be uniquely
human among extant species, Mehr et al. conjecture that the
basic elements of musicality are ancestral to all primates –just
as song is to all songbirds. Did musicality contribute to species
recognition when our ancestors formed groups or selected
mates, perhaps before the emergence of language? We are unable
to know how much musical predisposition we shared with our
evolutionary cousins –those we interbred with, and those we
didn’t. However, considering songbirds as a model system sug-
gests that the evolutionary implications of musicality need not
be limited to interactions within our own species.
Financial support. This study was supported by the NSF (NC & KS, grant
number BCS-1918824); and Vanderbilt University (KS & NC).
Conflict of interest. None.
Araki, M., Bandi, M. M., & Yazaki-Sugiyama, Y. (2016). Mind the gap: Neural coding of
species identity in birdsong prosody. Science (New York, N.Y.),354, 1282–1287.
Benichov, J. I., Benezra, S. E., Vallentin, D., Globerson, E., Long, M. A., & Tchernichovski,
O. (2016). The forebrain song system mediates predictive call timing in female and
male zebra finches. Current Biology,26, 309–318.
Benichov, J. I., & Vallentin, D. (2020). Inhibition within a premotor circuit controls the
timing of vocal turn-taking in zebra finches. Nature Communications,11, 221.
Colombelli-Négrel, D., Hauber, M. E., Robertson, J., Sulloway, F. J., Hoi, H., Griggio, M.,
& Kleindorfer, S. (2012). Embryonic learning of vocal passwords in superb fairy-wrens
reveals intruder cuckoo nestlings. Current Biology,22, 2155–2160.
Creanza, N., Fogarty, L., & Feldman, M. W. (2016). Cultural niche construction of
repertoire size and learning strategies in songbirds. Evolutionary Ecology,30, 285–305.
Hall, M. L. (2009). A review of vocal duetting in birds. Advances in the Study of Behavior,
40,67–121. doi: 10.1016/s0065-3454(09)40003-2.
Hoffmann, S., Trost, L., Voigt, C., Leitner, S., Lemazina, A., Sagunsky, H., …(2019).
Duets recorded in the wild reveal that interindividually coordinated motor control
enables cooperative behavior. Nature Communications,10, 2577.
Hudson,E.J.,&Creanza,N.(2021).Ornament,armament,or toolkit? Modelling how population
size drives the evolution of birdsong, a functional cultural trait. bioRxiv, 2021.04.29.442039.
Hudson, E. J., Creanza, N., & Shizuka, D. (2020). The role of nestling acoustic experience
in song discrimination in a sparrow. Frontiers in Ecology and Evolution,8, 99. doi: 10.
Hudson, E. J., & Shizuka, D. (2017). Introductory whistle is sufficient for early song rec-
ognition by golden-crowned sparrow nestlings. Animal Behaviour,133,83–88. doi: 10.
Marler, P., & Peters, S. (1977). Selective vocal learning in a sparrow. Science (New York,
Robinson, C. M., Snyder, K. T., & Creanza, N. (2019). Correlated evolution between rep-
ertoire size and song plasticity predicts that sexual selection on song promotes
open-ended learning. eLife,8, 44454. doi: 10.7554/eLife.44454.
Soha, J. A., & Marler, P. (2000). A species-specific acoustic cue for selective song learning
in the white-crowned sparrow. Animal Behaviour,60, 297–306.
Making music: Let’s not be too quick
to abandon the byproduct
School of Psychology, University of Nottingham Malaysia, Jalan Broga, 43500
Semenyih, Selangor Darul Ehsan, Malaysia.
It is premature to conclude that music is an adaptation. Given
the danger of overextending the adaptationist mode of explana-
tion, the default position should be the byproduct hypothesis,
and it should take very strong evidence to drag us into the adap-
tationist camp. As yet, the evidence isn’t strong enough –and
the proposed adaptationist explanations have a number of unre-
Mehr et al. and Savage et al. have both put forward interesting and
very reasonable adaptationist accounts of music –or more pre-
cisely, of certain aspects of musicality and musical behavior. I’m
more sympathetic to such accounts than I was before. On balance,
though, I think it’s still premature to conclude that music is an
adaptation, and more plausible to think that it’s a byproduct.
There are three main reasons for this.
First, a lot of the evidence adduced in favor of adaptationist
explanations of music is equally amenable to a byproduct expla-
nation. The cross-cultural universality of music is consistent
with the claim that music is an adaptation –but it’s also
120 Commentary/Mehr et al.: Origins of music in credible signaling
consistent with the claim that it’s a byproduct of other adapta-
tions that are universal but not music-specific (e.g., emotional
responsiveness to the prosody in speech, which cultures might
independently “learn”to trigger with melodies). The complex
design evident in music could come from biological evolution –
but it could also come from cumulative cultural evolution; after
all, smart phones and bureaucracies exhibit complex design as
well, but are clearly not adaptations. Children take to music
early and easily –but they also take to iPads and TV; sometimes
ease of acquisition is a result of culture evolving for our minds,
rather than the other way around. Damage to certain areas of
the brain impairs the ability to make or appreciate music –but
none of these areas is involved exclusively in music, and it’s pos-
sible that the areas in question evolved primarily for their non-
musical functions (which are presumably also impaired by dam-
age to those areas). Music-like abilities in nonhuman animals
show that traits of that kind can evolve –but they don’t show
that they necessarily did evolve in our species, as human culture
can sometimes independently discover traits that evolved in
other animals: The fact that leaf-cutter ants engage in something
akin to agriculture doesn’t imply that human agriculture is an
adaptation; similarly, the fact that various nonhuman animals
produce auditory displays doesn’t imply that human music is an
adaptation. In short, much of the evidence is ambiguous. Given
the danger of overextending the adaptationist mode of explana-
tion, the byproduct approach seems like the safer default position
in lieu of more decisive evidence.
Second, the byproduct approach has a number of advantages over
its adaptationist rivals. Uncontroversial adaptations, such as arms
and the basic motivations, are found in all typically developing
human beings and are reasonably similar across cultures, subcultures,
and historical periods. Music, in contrast, varies greatly from place to
place and from time to time, and many people spend little time mak-
ing or consuming it. These facts are easier to square with a byproduct
explanation than an adaptationist one. Even if one argues that certain
core features of music are found in every culture, it remains the case
that plenty of individuals within those cultures devote little time to
music, whereas almost every individual has arms and the basic moti-
vations. And even if one argues that, in traditional cultures, almost
every individual devotes substantial time to music, the fact that
many individuals in modern cultures do not is still surprising on
an adaptationist account –after all, even in modern cultures, every
typically developing human being uses language frequently, and it
would be surprising on an adaptationist account of language if this
were not the case.
Third and finally, the adaptationist accounts ofmusic proposed in
this dual treatment face a number of challenges that byproduct expla-
nations do not. If stronger social bonds are adaptive, as Savage et al.
argue, why not select directly for a tendency to bond more strongly,
rather than a tendency to make and enjoy rhythmically patterned
pitch-sequences and to bond with others who do the same?
Regarding Mehr et al.’s account, does it seem plausible that raiding
parties would be less inclined to attack a group that kept perfect
time than an equivalently fierce group whose rhythms were slightly
off, or that such a strategy would be particularly useful? Keeping
time isn’t important in chimpanzee territorial displays, so the closest
animal analogy doesn’t support the idea. Is music-making prowess a
reliable way to assess a group’s potential as allies? People could make
beautiful music together but be hopeless at hunting, making tools, or
doing anything else that might make an alliance valuable. Why not
assess the valuable abilities directly, rather than assessing people’s
musical chops? If rhythm evolved for territorial signaling, why
aren’t men notably more rhythmical than women, given that men
have historically done the bulk of the territorial displaying and
defense? If melody evolved for infant-directed song, why aren’t
women notably more melodic than men, given that women have his-
torically done the bulk of the infant care? Although some studies sug-
gest such differences (e.g., Miles, Miranda, & Ullman, 2016), the
broader literature is mixed and it’s certainly not obvious that the
sexes differ much in these domains. Is infant-directed song a reliable
signal of commitment in anyevolutionarilymeaningful way? It “tells”
the baby that it has the parent’s undivided attention at that particular
moment, while the parent is singing the song. However, the fact that it
has their attention in a context where it isn’t especially costly to the
parent doesn’t guarantee that the parent will prioritize the baby if
and when difficult trade-offs need to be made –for example, if the
parent has to choose to invest either in the baby or in one of the
baby’s siblings. A peacock can’t grow a decent tail unless it’sin
good condition; in contrast, it’s easy enough to sing a baby a song
then withdraw support later on, if one’s circumstances change.
I don’t claim that these difficulties are necessarily insurmount-
able, and I concede that some of the evidence presented in favor
of an evolved contribution to human musicality is at the very least
suggestive. However, the difficulties do hint that it’s premature to
accept an adaptationist account at this stage –and if I had to make
a bet today, my money would be on the byproduct approach.
Financial support. The author received no specific grant for this work from
any funding agency.
Conflict of interest. None.
Miles, S. A., Miranda, R. A., & Ullman, M. T. (2016). Sex differences in music: A female
advantage at recognizing familiar melodies. Frontiers in Psychology,7, 278–278.
Pre-hunt charade as the cradle of
Department of Sociology and Communication, Budapest University of
Technology and Economics, Egry J. u. 1., Budapest, 1111, Hungary;
Social Sciences (TK CSS) “Lendület”Research Center for Educational and
Network Studies (CSS-RECENS), Tóth Kálmán u. 4, Budapest, 1097, Hungary
Evolutionary Systems Research Group, Centre for Ecological Research,
Klebelsberg Kuno u. 3, Tihany 8237, Hungary.
Human language and human music are both unique communi-
cation systems that evolved in the human lineage. Here, I pro-
pose that they share the same root, they evolved from an
ancestral communication system yet to be described in detail. I
suggest that pre-hunt charade was this shared root, which helped
organize and coordinate the hunt of early hominins.
Commentary/Mehr et al.: Origins of music in credible signaling 121