Play and Mate Preference
Testing the Signal Theory of
Adult Playfulnesss
Garry Chick
Careen Yarnal
Andrew Purrington
The overwhelming majority of play research concerns juveniles. However, a fullunderstanding of the phenomenon requires knowledge of play and playfulness
across the life spans of those animals, including humans, who play in adulthood.
The authors investigate a theory of play based on Darwin’s concept of sexual selection that may account for the existence of play among adult humans. The authors
hypothesize that playfulness becomes a highly desired characteristic in potential
long-term mates but also that the reasons for desiring playful mates differ for males
and females. The authors suggest that for males, playfulness in females signals youth
and, hence, fecundity; for females, playfulness in males signals nonaggressiveness.
They test these hypotheses using mate-preference data. Key words: adult play andplayfulness; play and mate preference; play evolution; sexual selection
If a wild animal habitually performs some useless activity, natural selection
will favour rival individuals who devote the time and energy, instead, to surviving and reproducing. Nature cannot afford frivolous jeux d’esprit. Ruthlessutilitarianism trumps, even if it doesn’t always seem that way.
—Richard Dawkins, The God Delusion

Play is quintessential jeux d’esprit, but because nearly all, if not all,mammals, many birds, and members of numerous other species play (Burghardt2005), it also presents one of evolution’s most vexing problems. Play appears
to be not only nonutilitarian but is often downright dangerous. It seemingly
wastes time and energy, opens players to injury and occasionally even to death,and leads, at times, to a lack of vigilance that may expose them to predation(Bekoff and Byers 1998; Bjorklund and Pellegrini 2002; Fagen 1981; Pellegrini
and Bjorklund 2004; Symons 1978; for an alternate view see Martin and Caro
1985; Power 2000). So, why does play exist?
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American Journal of Play, volume 4, number 4 © The Strong
Contact Garry Chick at gchick@psu.edu

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In 1998 at a combined meeting of The Association for the Study of Play andthe Society for Cross-Cultural Research, one of us—Garry Chick—delivered akeynote address titled “What is Play For?” (Chick 1998, 2001). In it, he expressed
his worry about traditional theories of play (as described in, e.g., Ellis 1973) andtheir failure to explain adequately the existence of play. Most of these theories
are outdated and all but useless because they do not lead to testable predictions.
Additionally, and as important, they fail to address play and playfulness among
adults. (We regard play as the behavioral manifestation of playfulness that, inturn, is the propensity to engage in play.) In contrast, Chick proposed a theory,
based on Darwin’s concept of sexual selection, that is not only relevant to adultplay and playfulness but also permits the generation of testable hypotheses. Specifically, Chick postulated that play and the personal characteristic of playfulness,among adult humans, send signals, or messages, to the opposite sex of important
information regarding the signaler’s suitability as a long-term mate. Moreover,the content of the signals sent by males and by females differs. Through playand playfulness, males signal their nonaggressiveness while females signal their
youth and fecundity. This article presents and tests hypotheses based on Chick’s
signal theory of adult playfulness.

Proximate and Ultimate Cause
Chick’s proposal rested on an explicitly evolutionary perspective. Therefore, we
distinguish two types of explanation we believe apply to play and playfulness
to understand them from an evolutionary perspective. In biology, proximate
cause refers to something immediately responsible for some other action or
event. This contrasts with ultimate cause, generally a reference to an evolutionary explanation. In an influential 1961 paper, biologist Ernst Mayr wrote thatproximate and ultimate causes deal with how and why questions respectively.
For example, how do birds determine when to migrate? They migrate because
they have internal biological clocks that alert them to fly north (in the Northern Hemisphere) for reproduction and south for the winter. But, why did they
evolve such biological clocks and navigation skills in the first place? They did
so because otherwise they might freeze or starve in the northern winter. In thecases of insectivores (insect eaters) or frugivors (fruit eaters), their food supplies
disappear. Many raptors (meat eaters) and seedeaters do not migrate because
their food supplies remain relatively stable during winters. Therefore, seasonal

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migration depends on the availability of food, on protection from predators, andon mates and breeding locations (Mayr 1961). Disciplines such as physiology,
developmental biology, and molecular biology generally address how physical or behavioral traits function and thereby provide explanations in terms ofproximate cause. Evolutionary biology, behavioral biology, and some subfields
of ecology deal with the evolutionary history and adaptive functions of physicalor behavioral traits and, therefore, provide explanations in terms of ultimate
cause. Mayr argued that these two types of causes are distinct and that both arenecessary for a complete understanding of a phenomenon (but see Laland etal. 2011 for a revised view of the distinction in biology).

Proximate and Ultimate Cause in the Social Sciences
The notions of proximate and ultimate cause have had relatively little impact inmainstream social science (where ultimate cause is sometimes referred to as “distal
cause”). For both humans and other animals, many behaviors appear to derivefrom various motivations. Some of these motivations are biological, such as hunger, thirst, and sex. Each of these has both proximate and ultimate explanations.
Humans and other animals also perform tasks to receive external rewards,
such as money or food, or to avoid punishment. Under these conditions, people
or animals are often said to be “extrinsically motivated.” In addition, psychologists and social psychologists ascribe some actions to “intrinsic motivations,”
things that spark pleasure, feelings of achievement and self-worth, or personal
development, all presumably without external reward. The problem with attributing human behavior to extrinsic or intrinsic motivations is that both areproximate explanations and provide little information about why the motivations exist in the first place, which renders them incomplete. For example, ina brief comment on Chick’s sexual selection–based theory of play, DeKoven(2002) wrote “One more reaction I [had] to that article about ‘What is Play For?’[was that] the author covers everything in depth except the possibility that playmight be for fun.” DeKoven’s suggestion that play may exist because it is fun isa proximate explanation. Yes, play is for fun. But, why is it fun?
Play is fun for children and remains so for most adults. But, developmentally, we know that participation in physical play follows a curvilinear relationship with age, peaking in early adulthood. We also know that adult play in mostother playful animals declines even earlier—soon after adolescence—and evenmore dramatically. Although mothers, and occasionally fathers, play with theiroffspring, the overwhelming majority of play involving nonhuman animals

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occurs among juveniles (e.g., van Lawick-Goodall 1968; Bekoff and Byers 1981).
There are, however, a few significant exceptions such as some domesticated species—especially dogs—and, of course, humans.
We have bred dogs for guarding, retrieving, pointing, herding, and otherspecializations. Some breeds, such as Labrador retrievers, tend to be more playful in adulthood than herding and guard dogs, for example. Moreover, manyof the most playful breeds also exhibit pronounced neoteny, that is, they retain
juvenile characteristics such as droopy ears, short muzzles, heavy bodies, andrelatively short legs, especially compared to their wolf ancestors. In an illustration of how this may have happened, Russian biologists led by Dmitri Belyaev
began an experiment in selectively breeding the silver fox (Vulpes vulpes) in
1959. They chose animals for breeding based on their “flight distance” whichrefers to how close a human can approach an animal before it flees. (Basically, this is a measure of the animal’s tameness.) Belyaev and his colleagues
chose for breeding foxes with the shortest flight distances. After only the tenthgeneration, 18 percent of the foxes showed extremely tame behavior, much
like that of domestic dogs, and “by one month postnatal they become eager
to establish human contact, whimpering to attract attention and sniffing andlicking at humans, just like puppy dogs” (“Study of the Molecular Basis of
Tame and Aggressive Behavior in the Silver Fox Model,” n.d.). Domesticatedfoxes, then, are tame, want to interact with humans, show neonatal characters(e.g., droopy ears), and remain playful into adulthood (Trut 1999). It is possible, therefore, that when humans first selected wolves to tame, which led to
the first dogs, a suite of neonatal characteristics, including playfulness, werebyproducts of that process. We may also have selected dogs for playfulness,
specifically. Chick’s questions asked whether playfulness in adulthood emerged
through a process of self-domestication similar to the human domestication ofdogs and to the experiment with silver foxes. Other animals may practice suchself-domestication, as well. Hare, Wobber, and Wrangham (2011) hypothesizethat bonobo (Pan paniscus) behavior, compared to that of the chimpanzee, isthe result of self-domestication through the selection for nonaggressiveness.
Another hint is that, like Labrador retrievers, humans retain many neonatal characteristics compared to our closest evolutionary relatives—apes likechimpanzees and gorillas. These features include a rounded, vaulted cranium,
a juvenile face (flat, with small jaws and teeth, no brow ridges), forward positioning of the foramen magnum, delayed closure of the cranial sutures, anunrotated and unopposable big toe, and an extended period of playfulness

Play and Mate Preference(Bolk 1926). Apparently playfulness may be part of a suite of juvenile traits
retained into, and through, adulthood by some species. To better understandthe mechanism by which this could have happened, we must first briefly examine Charles Darwin’s theory of evolution by natural selection.

The Engines of Evolution
To explain both similarities and differences among animals and plants, Darwin
proposed three forces that drive evolutionary change. These are artificial selection, natural selection, and sexual selection. Artificial and sexual selection are
really subtypes of natural selection.
In chapter I of On the Origin of Species by Means of Natural Selection, “Variation under Domestication,” Darwin (1859) introduced selective breeding or
artificial selection. Artificial selection is the deliberate or, sometimes, accidental(Darwin called these “methodical” and “unconscious”) choice of humans tobreed plants or animals with particular, presumably desirable, characteristics
while those with undesirable characteristics are prevented from breeding—or, atleast, not encouraged to breed. Darwin detailed the breeding of racing pigeons,
popular for sport in Victorian England and a species with which he was particularly familiar. He noted that “One of the most remarkable features in ourdomesticated races is that we see in them adaptation, not indeed to the animal’sor plant’s own good, but to man’s use or fancy” (21). The breeding of modern
maize from teosinte (a wild grass), cauliflower, broccoli, kale, Brussel sprouts,
kohlrabi, and collard greens, as well as modern cabbage from ancient wild cabbage, or the great variety of modern dogs from their wolf ancestors illustrate
the power of artificial selection.
Darwin then introduced natural selection. He asked, “Can the principleof selection, which we have seen is so potent in the hands of man, apply undernature? I think we shall see that it can act most efficiently” (59). The theory of
evolution by natural selection assumes that individual members of any given
species vary among themselves. Stated simply, the principle of natural selection
says that if some aspect of this variation gives one member of a species an advantage, be it ever so slight, over another that helps it to survive and reproduce, itwill be naturally selected and passed on to descendants if the trait is heritable.
The descendants will resemble their parents, leading to the accumulation of thevariation and evolutionary change.

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Darwin also proposed sexual selection in The Origin of Species but gave
it book-length treatment in The Descent of Man, and Selection in Relation toSex (1871). Sexual selection comes in two varieties, competition and choice.
Competition occurs between members of the same sex, most often males, whoengage in contests that may include physical combat to collect and guard haremsof females, protecting nearly or totally exclusive sexual access to them. Size,
strength, aggressiveness, and weaponry (such as antlers, enlarged teeth, pincers,
or claws) are important in competition, and lesser males may never reproduce atall. Male competition may also involve possession of critical resources requiredby females, such as food or breeding sites.
Choice, the second variety of sexual selection, occurs between the sexes andis most often exercised by females. Through female choice, Darwin explained thegarish adornments characteristic of males of many species, especially birds. The
male peafowl’s (i.e., peacock) display is an exemplar of showy male decoration.
But bright coloration or other exaggerated characteristics may be cumbersome
and likely maladaptive from the point of view of exposure to predation. So, theyshould not exist. Darwin described sexual selection through female choice: “I
can see no good reason to doubt that female birds, by selecting during thousands of generations, the most melodious or beautiful males, according to theirstandard of beauty, might produce a marked effect” (1859, 66).
Experimental evidence supports the idea of female choice. Malte Andersson
and colleagues (1982; Andersson et al. 2002; Pryke and Andersson 2001, 2002)
studied female choice in the widowbird, a polygynous bird that nests in open
grasslands in Kenya. Widowbird males have bodies about the size of the North
American robin but also extremely long (approximately 50 cm.) tail feathers.
Females, on the other hand, have 7 cm. tails. Males attract females by flying low
over their territories with tail feathers fanned. After mating, females nest in tall
grass, and the males are not involved in rearing the young. Andersson (1982)
hypothesized that the elongated tail plays a role in mate attraction. He then led
an experiment wherein all of the males in an area were captured and treated in
one of four ways. Some were simply released as a control group to demonstratethat capture itself did not influence mating success. Birds in the second control
group had their tails cut but then replaced (glued back on). Andersson andcolleagues shortened the tails of birds in a third experimental group to about
14 cm. The researchers then used the leftover feathers to extend the tails of the
fourth group to about 75 cm. They found that females preferred the new longertailed males by a ratio of 4 to 1 over their short-tailed colleagues and about 3

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to 1 over the control birds. However, the longer tail feathers interfered with theflight characteristics of the second experimental group and probably placed it
at greater risk of predation. Hence, there are natural limits on the lengths (literally) to which males can go to attract females. Many other studies, both in thelaboratory and the wild, have also shown the power of sexual selection by female
choice (e.g., Endler 1983, 1986; Haines and Gould 1994).
Human males and females engage in both competition and displays to attract
mates, and both exercise choice. Competition comes in many forms, including
physical conflict, but also in displays with behavioral and material components.
Men may provide women with expensive gifts or equip themselves with expensive cars or clothing to demonstrate their skill at acquiring goods and necessities.
Women may wear garments or use makeup designed to enhance their looks andmake themselves appear younger, healthier, and more desirable (see Puts [2010]
for an excellent summary and analysis of research on sexual selection in humans).

Children’s Play
From an ultimate causal perspective, juvenile play must have future benefits for
playful animals at least as great as its immediate costs. Otherwise, it would never
have remained a behavioral trait of so many animals. The benefits of play common to all animals may include enhancing motor skills, learning social skills, anddeveloping cognitive abilities (Bekoff and Byers 1998; Burghardt 2005; Pellegrini
and Smith 1998; Smith 1982). Young humans may learn how to take on roles,
manipulate language, solve problems, and become more creative through play
(Lancy 1996; Rubin, Fein, and Vandenberg 1983).
Bock (2005) and his colleague (Bock and Johnson 2004) have developed
a perspective on children’s play based in evolutionary behavioral ecology. They
hypothesize that the forms and frequency of play mirror adult productive tasks inparticular ecological circumstances (Bock 2002, 2005). For example, in traditional
foraging societies, adult males do most of the hunting. Therefore, play relevantto the development of hunting skills—such as learning to track, snare, and spear
prey—should not only occur but should be more common among boys than girls(Bock 2005; Bock and Johnson 2004). Similarly, because many researchers thinkrough-and-tumble play serves as practice for fighting (Fry 1990; Groos 1898; Pellegrini 2002; Smith 1982) and find it more common among boys than among girls,
it should appear more frequently and take up more time in more belligerent socio-

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ecological cultures (Fry 2005) and in traditional hunting cultures (Bock 2005). Bockhypothesized that pretend play, often viewed as preparatory for adult competence
through practice and role playing, may be prevalent where direct practice would becostly or dangerous (e.g., where real food might be spoiled by unskilled preparationor where hunting could involve confrontation with dangerous predators). As such,it should be gender specific in order to complement adult roles in given social andecological contexts (Bock 2002, 2005; Bock and Johnson 2004).
Based on this theorizing, Bock made several predictions about children’s
work and play in traditional settings. For example, the amount of time devoted
to play and to work should vary inversely with age: older children work more
and play less. This means, first, that time allocated to the development of productive adult skills through play should decline in proportion to the degree ofadult competence achieved. Second, children will play more at activities that beara relationship to the subsistence strategy (e.g., foraging, agriculture) in which
the child will participate as an adult. Third, children will spend more time inplay forms that are related to gender-specific productive skills in the subsistence
ecology in which they will participate as adults. Bock and Johnson (2004; Bock2005) found strong support for these hypotheses in extensive time allocation,
economic, demographic, and experimental data gathered in a community in the
Okavango Delta of Botswana in the early to mid-1990s. In addition to the evidence for his hypotheses, Bock (2002) found that trade-offs between immediate
and future productivity significantly determined children’s play. Where children’s
work was economically viable, they worked. Where it was not, they played, but
their play generally reflected activities relevant to their household subsistence
economy. Time allocation research by Gurven and Kaplan (2006) among the
Machiguenga and the Piro of the Western Amazon basin in Brazil and Peru and
by Kramer (2005) in a Mayan village in the Yucatan produced similar results.
So, a perspective based in evolutionary human ecology seems to explain muchabout children’s play in terms of its ultimate causation: it is economically usefuland usually so in the long term. However, the work by Bock and his colleagues
applies only to children’s play. What of play among adults?

Adult Play
Adult play and playfulness present problems from an ultimate causal perspective because they do not appear to fit the same reasoning we apply to chil-Play and Mate Preference

dren’s play. Presumably, most of the skills that children need to be competent
adults have been learned by the time they reach adulthood or, at least, learning them in the context of play has given way to learning them in the context
of adult activities. The research by Bock and others (Bock 2002, 2005; Bockand Johnson 2004; Kramer 2005; Gurven and Kaplan 2006) indicates that assoon as children are productive at work, play with models of productive tasks
declines and disappears. With respect to adults, it is difficult to see how any
possible future benefits of play could outweigh its immediate costs (but see
Palagi [2006] for evidence of immediate benefits in the bonobo). Nevertheless,
adult humans do play, commonly into old age (e.g., Yarnal et al. 2008, 2009;
Yarnal and Qian 2011).
Adult play often simply extends children’s play. For instance, children
begin to play games with rules around the age of five or six (Piaget 1962; Elkind2007) and may continue these activities into late adulthood. Examples include
ball games—such as baseball, softball, soccer, and basketball—card games, andboard games. These may become more complex as cognitive skills increase
with age (e.g., Go Fish or Old Maid gives way to poker or bridge; Candy Landor Uncle Wiggily is replaced by Monopoly or chess). Adults engage in other,more cognitively sophisticated, activities compared to children such as wordplay, including puns and jokes that involve linguistic and rhetorical manipulations. “Horseplay” is a form of rough-and-tumble play often undertaken byadolescents and adults. Similarly, children’s play like cowboys and Indians orcops and robbers translates into adult play forms such as paintball. Adults engage
in presumably more sophisticated forms of sex play than children do, including
the aptly named “foreplay.”
According to The Entertainment Software Association (2012), the average
video game player is thirty-seven years old. Forty-two percent of video gameplayers are female, and a higher percentage of video game players are women(37 percent) than boys under eighteen (13 percent). Twenty-nine percent ofAmericans over the age of fifty play video games. Similarly, adults, including
older adults, commonly play with model machines, such as model airplanes,
cars, boats, and trains (Chick 2004), as well as real machines including bicycles,
snowmobiles, motorcycles, personal watercraft (e.g., the Jet Ski), and all-terrain
vehicles (Chick and Hood 1996). Older adult women also engage in a variety ofplay activities. For example, the Red Hat Society is a social play group for womenages fifty and over with more than thirty-eight thousand members in chapters
ranging in size from twenty to two hundred. Red Hatters don outrageous red

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hats, vivid purple outfits, “spiky heels and all manner of gee-gaws” to “strut
their stuff,” “hoot and holler” and publically demonstrate that “we ain’t deadyet” (Yarnal 2006). Some women play at bowling (Heuser, 2005), line dancing(Brown 2007), cruising (Yarnal 2004), and masking (Yarnal, et al. 2009). Adults,
like many other mammals, not only play with each other but also play with
their children—that we continue to do so when our offspring reach adulthood
separates us from other species.
Chick (1998, 2001) suggested both male and female adult humans prefer mates who are playful because playfulness signals desirable attributes inpossible mates. Earlier, Sigmund (1993) thought we may have bred “ourselves
into playmates” (207). He proposed we did so by preferring playful children
and, therefore, providing more care for them than for their less playful siblings.
Progeny choice refers to the way we select core over marginal offspring either
by neglecting weaker or otherwise low-quality young or by permitting sibling
rivalry to kill off siblings (Forbes and Mock 1998). Siblicide is phylogeneticallywidespread. It occurs among plants, insects, and mammals, though researchers
have probably studied it most among birds with respect to what they call “optimal clutch size” (Lack 1947; Mock, Drummond, and Stinson 1990). Because
selection through progeny choice is not random, it can increase the average
quality of offspring (Forbes and Mock 1998). Although parental preference
for, and enhanced care of, more playful children may occur, Sigmund (1993)
provided no evidence for it. Moreover, even if parents favor playful progeny,
selection for a trait in children does not mean it will be retained in adulthood.
On the contrary, juvenile playfulness declines precipitously with sexual maturity
in nearly all playful species.
Michael Ghiselin (1974, 1982) proposed that play, as well as art, science,
religion, and morals, are the products of artificial selection. He observed thatpeople who are playful are less likely to do harm to each other: “We seek theircompany and cherish them, and this may reasonably be expected to increase their
Darwinian fitness” (1982, 165). We agree with Ghiselin’s proposal and regard it
as a corollary to our own position. However, we believe the messages encodedin male and female playfulness differ while Ghiselin implies they should be thesame; therefore, we predict that selection pressures on males and females also
differ (cf. Trivers 1972) while he does not.
Finally, as we noted earlier, theories without testable hypotheses are oflittle value. Fortunately, sexual selection in humans has attracted considerable
attention in mate-preference research.

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Mate-Preference ResearchStudies of mate preferences have been around for a more than half a century(Hill 1945; McGinnis 1958; Hudson and Henze 1969) and have been conductedprimarily with college-aged adults. Early work was largely atheoretical, but recent
research has usually been based on Robert L. Trivers’s (1972) parental-investment theory. Trivers theorized that, since the female investment in offspring,
including ovulation, pregnancy, lactation, and child care, is almost always far
greater than that of males, females should choose mates who are willing and able
to provide the most resources for raising a family. This may include securing
food, protecting territories, or defending both the female and the young against
aggressors. Females would look for external indicators of this willingness andability in potential mates. Trivers also hypothesized that the sex with the greater
parental investment would also be the choosier in selecting mates and that, again,
this should be more characteristic of females.
Chick (1998, 2001) proposed that both females and males favor playfulness
in potential mates because it offers a relatively unambiguous signal of reproductively important information. For females, Chick (1998, 2001) hypothesized,
playfulness in males signals they are less likely to harm their mates and their offspring. That is, playful males are less dangerous than serious males (cf. Ghiselin1974, 1982). For males, female playfulness signals something entirely different:
it indicates youth and health, each a sign of fecundity.

Male Preferences in Mates
Because women’s ability to bear children declines over the course their lives, men
should seek youthful women as age and appearance strongly predict fertility
in females (Buss 1989). Standards of beauty differ across cultures, but humans
rarely if ever regard asymmetric features or features that indicate advanced age
or disease signs of beauty. According to Buss: “Features of physical appearance
associated with youth—such as smooth skin, good muscle tone, lustrous hair,and full lips—and behavioral indicators of youth—such as high energy and asprightly gait—have been hypothesized to provide the strongest cues to female
reproductive capacity (Symons 1979; Williams 1975). Sexual attraction andstandards of beauty are hypothesized to have evolved to correspond to thesefeatures. On this account males failing to prefer females possessing attributes thatsignal high reproductive capacity would, on average, leave fewer offspring thanwould males who do prefer to mate with females displaying these attributes” (2).

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Hence, as Buss (1985, 1989; Buss and Barnes 1986) hypothesized, males
would be more interested than females in the physical attractiveness of potential
mates while females would consider earning capacity in possible mates to be
more important than would males. Buss found support for these hypotheses,
and several other studies (Buunk et al. 2002; Hatfield and Sprecher 1995; Khallad
2005; Lippa 2007; Shackelford, Schmitt, and Buss 2005) provide similar results
across a variety of populations using a variety of methods.

Female Preferences in Mates
Male fertility depends less clearly on age and thus may be generally more difficult to assess on the basis of physical appearance. Therefore, again, the physicalappearance of males should be less important to females than female appearance is for males (Buss 1989). While this may be so, research suggests that maleappearance nevertheless has some importance for human females. Women findmen with athletic bodies, especially a V-shaped torso, more attractive than thosewith average physiques (Dixon et al. 2003, Li et al. 2006, Jonason 2007). Men
may bias exercise regimens to enlarge the upper body to obtain a V-shaped torso
favored by women (Jonason 2007).
Sexual-selection theory indicates that males compete for mating opportunities and females choose those who demonstrate superior resources in termsof material well-being but also that females consider genetic quality in making
such choices. Physical competition through play, games, and sport is an obvious
way in which human males demonstrate physical (and often strategic) qualities
such as speed, endurance, and strength (Manning and Taylor 2001). Males seemto believe that acumen in sports is important for mate choice and that athletic
ability is attractive to females (Walters and Crawford 1993). Schulte-Hostedde
and his colleagues (2008) suggest, if game and sports participation offers honest
signals regarding male quality, a number of hypotheses can be proposed. For
example, “participants in sport should have more sexual partners than nonparticipants, and the level of sport performance should also predict the numberof sexual partners” (114). Faurie, Pontier, and Raymond (2004) found that male
French students who competed in sports reported having more sexual partners
than did nonparticipants and, among athletes, performance levels correlated
positively with reported numbers of sexual partners. Caution is advised here
because Faurie and her colleagues provide only self-reported data, not behavioral data. It could be that better athletes are bigger liars than lesser men. The
number and extent of extramarital dalliances by a few well-known professional

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athletes supports the hypothesis, but data of high reliability and validity are rare.
The type of sports also may affect male displays of quality. Team sports
may permit the display of some positive qualities, such as cooperation andsociability, better than individual sports. In addition, team sports permit
comparison with a greater number of others than does individual sports participation (Schulte-Hostedde, Eys, and Johnson 2008). But female choice may
also include other criteria.
Females face serious problems when choosing a mate based on criteriaother than male appearance, resources, and genetic quality—both infanticide
and the physical abuse of females are common in many mammals. Male lions,for example, typically kill all of the suckling cubs in a pride after deposing apreviously dominant male. This serves to eliminate the progeny of another male
but also insures that females come into estrus quickly so that the newly dominant male or males can sire offspring. Male lions do not typically retain their
dominant position for long, so the only way to ensure that their genes pass tothe next generation is to reproduce quickly. Packer and Pusey (1983) estimatedthat about one-fourth of all lion cubs are victims of infanticide. Infanticide has
also been observed among various species of monkeys as well as among gorillas and chimpanzees. While infanticide has not been observed in orangutans,Wrangham and Peterson (1996) indicate “Most female orangutans are raped
regularly.” Battering females is relatively common among chimpanzees, although
not among gorillas: “Every female chimpanzee gets battered, some are raped, anda few have their infants killed. Many or even most gorilla mothers experience
infanticide—but they aren’t battered” (151).
Infanticide among humans is rare. Nevertheless, biological fathers are muchless likely than stepfathers to kill their children (e.g., Buss 1989; Harris et al.
2007). Daly and Wilson (1998) argued that an American child with one biological parent and one stepparent is approximately one hundred times more likely
to suffer infanticide than a child who lives with both biological parents. Temrin,
Buchmayer, and Enquist’s study (2000) based on data from Sweden contradicts
this view. However, a reanalysis, corrected for age differences in children livingwith a stepparent, shows that the Swedish data agrees with those from North
America, albeit more weakly (Daly and Wilson 2001). Evidence from modern
industrial societies, including Australia (Tooley et al. 2006) indicate that unintentional fatal accidents are higher for children living with a stepparent thanwith biological parents and, in the United States, that more financial resources
are spent on genetic offspring than on stepchildren (Anderson, Kaplan, and Lan-

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caster 1999). Marlowe (1999) found lower levels of male care for stepchildren
than biological children among the Hadza, a foraging society in Tanzania, as well.
According to Kyriacou et al. (1999), “Domestic violence is the most common cause of nonfatal injury to women in the United States.” Further, “thelifetime risk of severe injury as a result of domestic violence has been estimatedto be 9 percent for women, with a lifetime risk of up to 22 percent for any typeof injury from domestic violence. The risk of death from domestic violence isalso substantial; one third of the homicides of women in the United States arecommitted by a spouse or partner” (1892). The situation in other countries isa little better in some places but much worse in others. Results from a World
Health Organization study of domestic violence covered more than twenty-four
thousand women, aged fifteen to forty-nine, from fifteen sites in ten countries
around the world (Bangladesh, Brazil, Ethiopia, Japan, Peru, Namibia, Samoa,
Serbia and Montenegro, Thailand, and Tanzania). In thirteen of the fifteen sites,
35 percent to 76 percent of the women had been either physically or sexuallyassaulted since the age of fifteen. In every setting but one, a current or previous
partner, rather than a stranger or other individual, had perpetrated the assault(Garcia-Moreno et al. 2005).
Females of many species, including humans, have good reason to fear forboth the safety of their children and for themselves from males with whom they
have intimate relationships. But, how are they to judge if males are dangerous?
If Ghiselin (1974, 1982) and Chick (1998, 2001) are correct, playfulness in males
may signal nonaggressiveness. Playfulness may be part of a suite of both physicaland behavioral changes resulting from self-domestication for nonaggressiveness(cf. Hare,Wobber, and Wrangham 2012).

Forms of Sexual Signaling
Humans and other animals exhibit a variety of signals regarding their value asmates. These include visual, olfactory, auditory, taste, and behavioral cues. We
have already mentioned birds—the males of many species, common cardinals
being one, exhibit elaborate coloration; others, like widowbirds, feature elongated tails. Some mammals, such as deer, moose, and elk, sport antlers, which
are generally sexual weaponry, used in combat with other males. The extinct
Irish elk (it was not exclusively Irish and was actually a deer, not an elk), had
antlers that could span twelve feet, weigh ninety pounds, and grew anew eachyear (Coyne 2009). All these characteristics provide visual signals of potency
to both other males and to females. Aurelio Malo and colleagues (2005), forPlay and Mate Preference

example, indicate that antler size is an honest signal of sperm quality and quantity in red deer. Sexual signals such as elaborate calls, songs, scents, and mating
displays are common among animals and almost always appear maladaptivein that they might draw predator attention and consume copious amounts ofenergy (Coyne 2009).
Among humans, visual and behavioral signals play a critical role in sexual displays although olfaction (sometimes stimulated by perfumes, colognes,
deodorants, and other fragrances) also helps. Women in many societies commonly
attempt to enhance their secondary sexual characteristics and youthful appearance
through structure enhancing undergarments or added coloration (from lipstick,nail polish, and rouge, for example). Men may wear jackets with shoulder pads toemphasize a V-shaped torso, but much of their sexual signaling is behavioral, particularly displays of wealth, prestige, and power. As Puts (2010) indicates, “Beauty,
fashion, and physical fitness are so important in the United States that they havebecome multi-billion dollar industries” (157). And indeed, physical appearances
are important worldwide in male selection. They are not, however, the only forms
of sexual signaling. Sundie et al. (2011) illustrated in three experiments that conspicuous consumption is a strategy used by men with short-term mating in mind
and that women accurately interpret it as the men intend it. The study concludes
that conspicuous consumption by males is not just a display of economic prowess
but part of a signaling system devoted to short-term mating.
While the physical appearance of a female can clearly signal her reproductive potential, a man’s ability to invest economically in offspring is less obvious,
though potent when recognized. In a comparative study of five widely dispersed
foraging groups (the Ache of the upper Amazon basin, the Hadza of East Africa,
the !Kung of southern Africa, the Lamalera of Indonesia, and the Meriam ofMelanesia), Smith (2004) found that success as a hunter correlates with demographics such as overall “fertility, number of mates, offspring survivorship, andlifetime reproductive success” (343). Indeed, he reported gains in reproductive
success (the number of surviving offspring) between 50 percent and 100 percent for successful hunters. Marlowe (2003) reported that Hadza women cite
“good hunter” as the single most valued trait in a potential mate while Wiessner(2002) found that better hunters among the !Kung had 50 percent higher fertility than poor hunters. The better hunters also had nearly double the numberof surviving offspring although their wives were neither more numerous nor
younger. Smith (2004) reported that skilled hunters in all groups enjoy prestige
and high social status.

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Playfulness as a Preferred Trait in Potential Mates
While many studies have addressed the importance of different characteristics
to men and women in their mating preferences, studies that include playfulness
are conspicuously absent (Chick 2001). Buss (1989) examined characteristics
linked to physical attractiveness, age, earning ability, ambition and industriousness, chastity, and health. Greiling and Buss (2000) explored factors that
may lead to infidelity in women including what characteristics they mightlook for in other men, but playfulness was not included among the traits theyquestioned participants about. Koyama, McGain, and Hill (2004) reexaminedthe difference in rankings of the traits from Buss (1998) and found that the
rankings did not significantly differ in cultures with more gender equality.
Schmitt (2005) studied the socio-sexuality of 14,059 people in forty-eightnations but did not address the topic of playfulness. McGraw (2002) examined the degree to which members of the opposite sex in several geographicallocations across the United States found varying personal characteristics to be
attractive. He intended to determine if the desirability of such traits as physicalattractiveness and resource-accruing ability differed based on the conditions
in one’s local environment, such as living in a more expensive city. Unfortunately, none of these studies included characteristics indicative of playfulness
among the traits examined.
Clearly not much research exists on playfulness as a desirable characteristicof potential mates in humans. To have some standard against which to compare
the desirability of playfulness as a trait in mates, we decided to replicate, in part,the study by Buss and Barnes (1986) using their list of thirteen possible characteristics of prospective mates that individuals might seek. We added playful,sense of humor, and fun loving to include the concept of playfulness in the list.
(We began with a list of thirty-five traits as part of a larger study. A factor analysisof this larger data set provides several factors, one of which consists of playful,sense of humor, and fun loving. We termed this factor “playfulness.” Our goalin this article is to see how these traits compare in desirability to the thirteen
used by Buss and Barnes.)
Males and females both value a sense of humor in potential mates (e.g.,
Daniel et al. 1985; Feingold 1992). However, experimentally manipulating humor
has resulted in the paradox that, while women prefer men who produce humor,
men show no corresponding interest in humorous women (Bressler and Balshine
2004; Lundy, Tan, and Cunningham 1998). Miller (2000, 2001) has hypothesizedthat both the ability to produce and to appreciate humor evolved by sexual

Play and Mate Preference

selection: the production of humor signals genetic quality, and its appreciation signals sexual interest. If this is the case, women may prefer men who can
produce humor while men may favor women who enjoy their humor (Bressler,
Martin, and Balshine 2006). Hence, a sense of humor appears to be an importantfeature in mate preference. However, we are unaware of any mate- preference
research considering playfulness in detail or examining fun loving at all. We
added fun loving because it seemed to capture some of the proximate qualitiesof play and playfulness.

Hypotheses
Our general hypothesis was simply that playfulness, a sense of humor, and funloving would be ranked high, specifically, in the top half, of the list of sixteen
traits. Because we wanted to make our study consistent with Buss and Barnes’s,
we did not include negative traits, such as aggressive, dominant, or physicallyabusive that might have permitted us to determine whether there is a difference
between males and females on these traits. We would have expected females
to rate them more negatively than males based on our conjecture that females
choose playful males because they are less likely to harm females and their children. However, two of the sixteen traits, kind and understanding and easygoing,
if rated higher by females than by males, are at least consistent with the ideathat females prefer mates who would not be aggressive toward them. Hence,
we hypothesize that females will rate these traits in a potential mate as moredesirable than males will rate them in females. We also anticipated that males
would rate physical attraction higher than females because it fits our conjecturethat males are interested in playful, youthful, fecund females and is consistent
with Buss and Barnes’s results. In addition, we hypothesize that healthy and good
heredity also suggest fecundity and, therefore, that males will rate them as moredesirable in females than females will in males.

The Research
SampleOur study included 254 undergraduate students as informants. All wereenrolled in a large introductory course on recreation and leisure. About half of

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the sample (n=132) completed an in-class paper survey during a fall semester
while the remainder (n=122) completed the same survey online in a subsequent semester. We first examined the results for the effects different administration methods might have on the students and the study, but we found nodifferences between the two groups. None of the students was younger thaneighteen or older than twenty-six (mean=20.32). Unfortunately, the gender
distribution was far from equal: 164 males and 89 females (one case missing).
Three students indicated they were married, but the remainder identified
themselves as single (seven cases missing). Eighty-three students were in
their fifth semester at the university, the median and modal response, with therange between the first and the ninth semester. The survey was distributed asa class participation assignment, worth five points on the participants’ final
grades if they returned completed surveys. The portion of students returningquestionnaires reached 85.7 percent.
In general, researchers must view data from university undergraduates withextreme caution, and this study is no exception. Henrich, Heine, and Norenzayan(2010) have called such samples “Western, Educated, Industrialized, Rich, and
Democratic” (WEIRD). Henrich and his associates claim that WEIRD subjects,
rather than being typical, are “particularly unusual compared with the rest of thespecies—frequent outliers” and that “members of WEIRD societies, including
young children, are among the least representative populations one could findfor generalizing about humans” (61). However, for this research, a sample ofundergraduates was attractive because the great majority of students (92 percent) were between the ages of eighteen and twenty-two, near their peak levelof interest in sexual partners.

Procedure
We used a modified version of a survey employed by Buss and Barnes to determine
mate preferences. They based their report (1986) on two studies they conducted.
In their first study, they asked ninety-two married couples to complete the MaritalPreferences Questionnaire (Gough 1973) and a battery of additional questions
designed to measure personality. The Marital Preferences Questionnaire asks about
a broad range of traits the subject might find desirable in a mate. It consists ofseventy-six alphabetically ordered items, such as adaptable, affectionate in nature,
dominant, intelligent, physically attractive, and witty. Buss ands Barnes instructed
respondents to rate the desirability of the traits on a 5-point Likert-type scale.

Play and Mate Preference

Buss and Barnes’s factor analysis of the data identified nine interpretablefactors. For their second study, Buss and Barnes then used these factor-analysis
results to develop a short list of traits and asked a second sample of fifty male andfifty female undergraduates to rank them. For the most part, Buss and Barnes
chose the items from their analysis with the highest factor loading from eachof the nine factors. However, they kept both intelligent and creative—althoughthese traits fell in the same factor—“because of their conceptual distinctiveness” (567). They also included good earning capacity and physically attractive
because these revealed large gender differences in their first sampling. Finally,
they included good heredity on the basis of literature that suggested its importance in mate preference.
These procedures resulted in thirteen items: kind and understanding,
exciting personality, intelligent, physically attractive, healthy, easygoing, creative, wants children, college graduate, good earning capacity, good heredity,
good housekeeper, and religious. As we indicated, we added fun loving, senseof humor, and playful to this list. Buss and Barnes asked those in their second
sample to rank order the thirteen characteristics. However, we asked students
to rate each of the sixteen characteristics using a scale from 1 to 10—with 1 as“not at all desirable,” 6 as “moderately desirable,” and 10 as “extremely desirable.” We did not provide anchoring descriptions for the other numbers. We
chose not to use rank ordering for two reasons. First, we felt that we would
get higher quality data by not doing so. That is, although our Likert-type
rating scales produced ordinal data, they offered informants the opportunity
to provide more interval-like responses than rank ordering, including tied
responses. Second, we felt that rank ordering sixteen items would be pressing
the cognitive limits of our informants. Rank ordering eight or even ten items
is fairly easy. Rank ordering sixteen is not.
Each questionnaire concluded with several demographic questions. We
asked the students to provide their gender so that we could analyze the responses
of males and females. We also asked each to note his or her major, semester
standing, desired ages at marriage, and desired ages of partner (how many years
younger, how many years older, or same age) and to rank his or her family
income and grades on a scale of below average, average, and above average.
Finally, the survey ended with an open-ended question asking how many children the informant would like to have. Buss and Barnes asked this question, so
we added it as a further basis of comparison with their study.

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Results
Figure 1 below shows the rank order of traits determined by Buss and Barnes
and the same traits, with the addition of playful, sense of humor, and fun loving, from our data. (We refer to our study in all figures as CYP—Chick, Yarnal,
and Purrington.) Because we used a 10-point rating scale, we transformed our
results to rank orders to permit comparison.
Figure 1 shows that playfulness ranks fifth overall but fourth as a trait
females desire in males. A sense of humor ranks first overall while fun loving
ranks third overall and third for males and females respectively. Our hypothesisthat these three traits should rank in the upper half of the full list of sixteen
finds ample support. To show that our sample and that used by Buss and Barnes
were similar, we correlated the rank ordering of the thirteen traits common toboth Buss and Barnes’s and our sample using Spearman’s rho. The correlation
between Buss and Barnes’s total sample and our total sample is .83 (n=13).
The high correlations between the rankings by males and females in Buss andBarnes’s sample and in our sample (figure 2) indicate that the two groups ranked

Buss and Barnes
BothFM
Playful

Both
5
1
3

Sense of humor
Fun loving
Kind and understanding
Exciting personality

12Intelligent
Attractive

3
4

Healthy
Easygoing

5
6

Creative
Wants children

78College graduate
Good earning capacity

910Good heredity
Good housekeeper

11
12

Religious

13

1
2
3

1
2
3

6
5

4
5

4
7

6
8

10
8

7
9

9
11

11
10

12
13

12
13

2
7
6
10
4
8
15
9
11
14
12
13
16

CYP
F

M

4

5

2
3
1

1
3

5
6
11
8
7
15
9
10
13
14
12
16

2
7
6
9
4
8
15
10
11
14
12
13
16

Figure 1. Rank orders of traits in Buss and Barnes and present study (CYP)Play and Mate Preference

Buss and Barnes
Females
Males
Buss and Barnes
Males

0.934

CYP
Females

0.866
13

0.857
13

0.004

0.003

0.835
13

0.890

CYP
Males

CYP
Females

13
0.000

0.006

13
0.001

0.947
16
0.000

Figure 2. Correlations (Spearman’s rho) between common items in CYP study
and Buss and Barnes (Sidak adjusted p values below number of cases)

the traits very similarly although the correlations within each sample are higher
than the correlations between the two samples. This may be because the datacollections took place more than twenty years apart and in different parts of theUnited States (ours in an Eastern university, theirs in a West Coast university).
Figure 3 provides the number of cases, minimum and maximum values,means, and the standard deviations for characteristics that females, males, andthe total sample find desirable in mates.
We found kind and understanding to be the highest ranked trait thatfemales sought in males, a result which duplicates Buss and Barnes. However, asense of humor, fun loving, and playful rank second, third, and fourth among
traits females sought in males. Males rate sense of humor first among the traits
they sought in females, with fun loving third, and playful, fifth. They also rate
kind and understanding very high, second among the sixteen characteristics.
Figure 3 shows that the three items we added to the Buss and Barnes list,
sense of humor, fun loving, and playful, rank first, third, and fifth, respectively,
among the sixteen items for the total sample. None was rated lower than 4on the 10-point scale while, among the other characteristics, only intelligent
received no scores below 4. The results clearly support our main hypothesisthat sense of humor, fun loving, and playful would rank in the upper half of
the attractive traits.

427

89
89
89
89
88
89
89
89
89

Healthy
Easygoing
Creative

Wants children

College graduate
Good earning capacity
Good heredity

Good housekeeper
Religious

1
1

1
1
1

1

3
2
1

4
6
5
6
3
5
3

Min2

7.19
5.74

7.85
6.91
6.60

8.00

8.10
8.12
6.51

8.39
9.00
8.78
9.11
8.34
8.21
7.63

Mean

164
164

164
163
164

163

163
164
163

163
164
164
164
164
164
164

n

1
1

1
1
1

1

4
5
1

4
4
5
2
5
5
4

Min2

6.83
5.57

7.24
6.71
7.23

8.04

8.65
8.28
6.17

8.48
9.01
8.70
8.74
8.30
8.37
8.15

Mean

2.08
2.76

2.56
2.22
2.02

2.08

1.29
1.40
2.13

1.19
1.12
1.17
1.28
1.37
1.35
1.39

Std. Dev.

254
254

253
253
254

253

253
254
253

252
254
254
254
254
254
254

n

1
1

1
1
1

1

3
2
1

4
4
5
2
3
5
3

Min2

6.96
5.61

7.44
6.78
7.01*

8.02

8.46*
8.22
6.28

8.44
9.00
8.72
8.87*
8.31
8.32
7.96*

Mean

2.05
2.76

2.51
2.20
2.15

2.23

1.45
1.51
2.17

1.24
1.11
1.15
1.22
1.41
1.36
1.50

Std. Dev.

Combined ratings1

Figure 3. Descriptive statistics for female ratings of preferred male characteristics, male ratings of preferred female
characteristics, and combined ratings for both genders

1.99
2.72

2.38
2.19
2.33

2.49

1.65
1.71
2.23

1.32
1.11
1.10
1.07
1.51
1.37
1.65

Std. Dev.

Male ratings1 of female

AMERICAN JOURNAL OF

1 Scale: 1 = Not at all desirable to 10 = Extremely desirable
2 All characteristics received a maximum rating of 10.
* Significant difference between males and females at the .05 level.

88
89
89
89
89
89
89

PlayfulSense of humor
Fun loving
Kind and understanding
Exciting personality
Intelligent
Physically attractivenFemale ratings1 of male428
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Play and Mate Preference

We also examined the hypothesis that males would prefer in females
those traits suggesting youthfulness and health more than females would prefer the same traits in males. We compared male with female ratings, using
a two-sample t-test (with unequal variances), for the degree to which they
preferred physically attractive mates (males = 8.15, females=7.63), healthymates (males=8.65, females=8.10), and those with good heredity (males=7.23,
females=6.60). The difference between males and females was significant forphysically attractive (t=2.51, df =155.92, p=.013, Cohen’s d=.402), healthy (t=2.723, df =148.28, p =.007, Cohen’s d =.447), and good heredity (t=2.149,
df =159.57, p =.033, Cohen’s d = .340). (We used Cohen’s d to measure effectsize for the t-tests. Cohen’s d is calculated by dividing the difference between
the two sample means by the standard deviation. Using the pooled standard
deviation is most common with independent samples. Cohen’s d ranges from0 to infinity with values between 0 and .2 indicating a small effect; those near.5, a moderate effect; and those of .8 and above, a larger effect.) Similarly, we
compared values for female preferences in males to test the hypothesis thatfemales prefer playful males because such males are less dangerous than nonplayful males. These traits include kind and understanding and easygoing. As
expected, females rated kind and understanding as more desirable than males
did (females=9.11, males=8.738; t =2.479, df =209.029, p =.014, Cohen’s d=.313). Female and male preferences did not differ with respect to easygoingas a preferred trait in a mate (females = 8.124, males = 8.28, t = 0.742, df =152.221, p = .460).
Finally, we examined the two traits that interested Buss and Barnes,
that is, good earning capacity, in addition to physically attractive, as indicatedabove. Buss and Barnes hypothesized that females would rank good earning
capacity in males higher than males would in females. Males, on the other
hand, should rank physical attractiveness in females higher than females would
rank the desirability of this trait in males. As indicted above, males rated goodearning capacity at 6.71 (sd = 1.22) while females rated the trait at 6.91 (sd= 2.19). While the rating for females appears to be slightly higher, the difference is not statistically significant (t = 0.684, df = 182.82, p = .495). As noted
above, males preferred physical attractiveness in females significantly higher
than females preferred it in males. Kind and understanding, healthy, physicallyattractive, and good heredity were the only traits rated significantly differently
by males and females.

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Discussion
A complete understanding of why humans—juveniles and adults—play requires
both proximate and ultimate explanations. These do not conflict but complement each other (Mayr 1961; Laland et al. 2011). The results we report here
support Chick’s (1998, 2001) hypothesis that adult playfulness results fromsexual selection and signals positive qualities to potential long-term mates. We
did not design our set of personal traits explicitly to test the hypotheses thatfemales prefer playful males because such males are less dangerous to them andtheir children or that males prefer playful females because playfulness connotes
fecundity. Nevertheless, males rated three traits characteristic of female fecundity
as significantly more desirable in females than females rated them in males, andfemales rated one of two traits characteristic of male nonaggressiveness as moredesirable than males rated them in females. Hence, we conclude that these firsttests of the signal theory of adult playfulness support or are, at least, consistent
with our hypotheses. However, there are several caveats to consider with respect
to the research and our conclusions.

“You Can’t Always Get What You Want”
The 1969 Rolling Stones’ song title expresses succinctly a major problem withmate-preference research that asks subjects to rate the desirability of certain traits
in potential mates. That is, there is no guarantee that individuals who claim toseek these traits actually find them. The fact that those sampled tended to ranksense of humor, fun loving, and playful at or near the top of the list of sixteen
characteristics does not mean that the mates they have selected or will selectactually exhibit these traits (cf. Perussé 1994). As Perussé recognized, “Mostresearch on mate choice in modern societies is based on data that may or may
not reflect actual mating behavior” (255). Mate-preference data, such as ours,
deal in ideals, not actual behavior.
Different methods also frequently seem to provide different results. For
example, Pillsworth (2008) first examined stated preferences for traits among theShuar, a group with a hunting and horticulture economy. She found that bothmales and females rated physical attractiveness at the bottom of a list of nineteen
personal traits. In a second study, informants were asked to rate twenty-eight
photographs of opposite-sex peers in terms of how desirable each would be as along-term romantic partner as well as in terms of eight characteristics, such as
physically attractive, intelligent, and hardworking. In this study, for both males andPlay and Mate Preference

females, Pillsworth found a significant correlation between the ratings of a target
individual’s physical attractiveness and his or her desirability as a sexual partner.
Her results showed, therefore, that Shuar men and women exhibit similar preferences for physical attractiveness in a long-term partner but also whether physicalattractiveness rates high or low depends on the method of data collection.
Other methods used in mate-choice and mate-preference research include
speed dating, where individuals meet several potential partners in succession anddecide which they would like to see again. Under these conditions, both men andwomen appear to base their decisions about possible partners almost entirelyon traits they observe. Kurzban and Weeden (2005), for example, found thatwomen do not use indicators of status or resources in their choices. Peter Todd
and his colleagues (2007) found that speed-dating choices differed substantiallyfrom participants’ stated preferences in partners. The authors suggest that thecognitive processes that underlie mate preferences may be quite different thanthose for mate choices.
On the other hand, Burriss, Welling, and Puts (2011) have shown, in a laboratory study, “that women’s preference for masculinity in unfamiliar men’s faces
is predicted by their partner’s self-rated masculinity” (1026). In turn, the way
men rated their own masculinity correlates strongly with the way their partners
rated it. The authors conclude, “This study shows that women’s preference for
masculinity is reflected in the masculinity of the men with whom they partner”(1026). They did not find a correlation between preferences and independent
ratings of facial masculinity, however, and infer that other variables, such as
body type, voice, height, or behavior may influence choice.
Finally, as noted above, the great majority of mate-preference studies are
based on WEIRD samples, often college students (Henrich, Heine, and Norenzyan 2010), with only a few from non-Western groups such as the Hadza of
Tanzania (Marlowe and Wetsman 2001), the Zulu of South Africa (Tovée et al.
2006), and the Shuar of Ecuador (Pillsworth 2008). Future research must involve
methods to address both stated mate preferences and actual mate choices anduse representative samples of individuals from cultural and ecological settings
around the world to avoid biases. Moreover, playfulness and related traits must
be examined in conjunction with a much larger set of possible individual characteristics, both positive and negative, in order to further test our hypotheses.

Other Motives for Adult PlayIn his 1973 cross-cultural study, Richard G. Sipes tested two competing theories

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P L AY s SPRING 2012of sports participation and warfare. He sought to explore what he termed “combative sport.” Combative sports may involve either individual contests, such as
wrestling, or group contests, such as American football, but must involve real or
potential body contact that is direct or that involves real or simulated weapons
or, if actual body contact is absent, the use of real or simulated weapons against
real or simulated humans.
One position, the Drive Discharge Model, posits that individuals build up
aggressive feelings over time that they can discharge through participation ineither warfare or combative sports. Sipes hypothesized that, if the Drive Discharge Model proved correct, there should be an inverse relationship between
the presence of combative sports and warfare because the aggressive tendencies
could be discharged through either.
The other position, termed the Culture Pattern Model, indicates that
there should be a direct correlation between the presence of combative sports
and warfare because such sports provide good training for war. Using a small
cross-cultural sample (n=20), Sipes found strong support for the Culture
Pattern Model.
Chick, Loy, and Miracle (1997) reexamined warfare-combative sports relationship with a substantially larger cross-cultural sample (n=110) and foundgeneral agreement with Sipes’s results. The strongest results they found, however, involved the presence of warfare and what they termed “sham combats,”
that is, mock combats and training activities, rather than between warfare andeither individual or team combative sports. Chick and Loy (2001), again usinga cross-cultural sample, found that childhood training in aggressiveness, fortitude, and competiveness among males serves a preparatory role for some sports
and warfare. So, participation in sports may prepare men for war, keep them
prepared, and provide more opportunities for learning aggression than are available to women (Archer 2009).
Males participation in sports may also reliably signal physical and, perhaps,
mental qualities to females in addition to competition for status (De Block and
Dewitte 2009; Faurie, Pontier, and Raymond 2004). In a cross-cultural study,
Deaner and Smith (2012) show these possibilities are sex specific to males. They
found that there are more sports for males, in general, and that hunting-related
and combative sports are almost exclusively male pursuits. Hence, adult maleparticipation in forms of competitive play such as sports—and especially combative sports—may provide training for other activities, including war, but may
also be seen by females as a marker of genetic quality and status. However, itPlay and Mate Preference

seems unlikely that either training for war or the signaling of genetic quality
by participating in sports occurs among females because of the large genderdifference in sports, particularly in hunting and combative sports (Deaner andSmith 2012).

Summary
While there are problems with mate-preference research based on ratings ofdesirable traits in long-term mates, we find our results encouraging. It seems
to us that signaling one’s virtues as a potential long-term mate through playfulness is not farfetched—nearly all our results support or are consistent with
the idea, and none contradict it. Otherwise, like elaborate tail feathers, enormous antlers, or displays that attract the attention of predators, adult playfulness is extremely difficult to explain. We believe that we bred playfulness into
ourselves, intentionally or otherwise, but not by preferring playful children,
as claimed by Sigmund (1993), nor primarily through artificial selection, as
suggested by Ghiselin (1974, 1982). The work of Belyaev and his colleagues
with foxes illustrates how easy it was to breed playful adults even when thetrait under selection—flight distance or tameness—does not overtly include
the propensity to play as adults. Selection for tameness results in neoteny and,in turn, neoteny appears to carry a suite of ancillary traits, including playfulness, with it. We do not feel that it is a major step to suggest that adult playis therefore a signal that conveys nonaggressiveness (tameness?) to females
when exhibited by males. And, because it is so characteristic of juveniles,
female play and playfulness communicate youthfulness, health, and, hence,
fecundity to males.
There are signals that indicate playfulness and the desire to play. These
include the play face, the play bow, and so on, but, if we are right, play itself is also
a signal among adults. Since we are proposing sexual selection as the explanation for why both males and females prefer playfulness in possible mates, we donot believe that our hypothesis is directly relevant to juveniles. While juveniles
are sure to prefer other playful juveniles, parents may prefer playful juveniles,
and so on, we think the reasons for doing so, described above, are not the sameas among adults. In an ultimate sense, play has helped make us who we are, as
adults; and in a proximate sense, it has made being an adult much more funthan it might have been otherwise.

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