Family Matters: Rethinking the Psychology of Human Social Motivation - Institut für Psychologie
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872986
research-article2019
PPSXXX10.1177/1745691619872986Ko et al.Family Matters
ASSOCIATION FOR
PSYCHOLOGICAL SCIENCE
Perspectives on Psychological Science
Family Matters: Rethinking the Psychology 2020, Vol. 15(1) 173–201
© The Author(s) 2019
Article reuse guidelines:
of Human Social Motivation sagepub.com/journals-permissions
DOI: 10.1177/1745691619872986
https://doi.org/10.1177/1745691619872986
www.psychologicalscience.org/PPS
Ahra Ko1 , Cari M. Pick1, Jung Yul Kwon1 , Michael Barlev1,
Jaimie Arona Krems2, Michael E. W. Varnum1 , Rebecca Neel3,
Mark Peysha4, Watcharaporn Boonyasiriwat5, Eduard Brandstätter6,
Ana Carla Crispim7, Julio Eduardo Cruz8, Daniel David9,
Oana A. David9, Renata Pereira de Felipe7, Velichko H. Fetvadjiev10,
Ronald Fischer10,11, Silvia Galdi12, Oscar Galindo13, Galina Golovina14,
Luis Gomez-Jacinto15, Sylvie Graf16, Igor Grossmann17, Pelin Gul18,
Takeshi Hamamura19, Shihui Han20, Hidefumi Hitokoto21,
Martina Hřebíčková16, Jennifer Lee Johnson22, Johannes A. Karl11,
Oksana Malanchuk23, Asuka Murata24, Jinkyung Na25, Jiaqing O26,
Muhammed Rizwan27, Eric Roth28, Sergio Antonio Salgado Salgado29,
Elena Samoylenko14, Tatyana Savchenko14, A. Timur Sevincer30,
Adrian Stanciu31, Eunkook M. Suh32, Thomas Talhelm33, Ayse K. Uskul34,
Irem Uz35, Danilo Zambrano36, and Douglas T. Kenrick1
1
Department of Psychology, Arizona State University; 2Department of Psychology, Oklahoma State University;
3
Department of Psychology, University of Toronto; 4The Coaching Institute, San Diego, CA; 5Faculty of Psychology,
Chulalongkorn University; 6Department of Economic Psychology, Johannes Kepler University Linz; 7Instituto
de Psicologia, Universidade de São Paulo; 8Department of Psychology, Universidad de los Andes; 9Department
of Clinical Psychology and Psychotherapy, Babeş-Bolyai University; 10School of Psychology, Victoria University
of Wellington; 11Behavioral Neuroscience Lab, Instituto D’Or de Pesquisa e Ensino, Rio de Janeiro, Brazil;
12
Department of Psychology, University of Campania Luigi Vanvitelli; 13Department of Psychology, Universidad
de los Andes; 14Institute of Psychology, Russian Academy of Sciences; 15Department of Social Psychology, Social
Anthropology, Social Work and Social Services, University of Malaga; 16Institute of Psychology, Czech Academy
of Sciences; 17Department of Psychology, University of Waterloo; 18Department of Psychology, Iowa State University;
19
School of Psychology, Curtin University; 20School of Psychological and Cognitive Sciences, Peking University;
21
Humanities, Fukuoka University; 22Department of Anthropology, Purdue University; 23Institute for Social Research,
University of Michigan; 24Center for Experimental Research in Social Sciences, Hokkaido University; 25Department
of Psychology, Sogang University; 26Department of Psychology, Aberystwyth University; 27The Delve Pvt Ltd,
Islamabad, Pakistan; 28Behavioral Sciences Research Institute, Universidad Católica Boliviana; 29Department
of Administration and Economics, Universidad de La Frontera; 30Department of Psychology, University of Hamburg;
31
Institute for Gerontology, Vechta University; 32Department of Psychology, Yonsei University; 33Booth School of
Business, University of Chicago; 34School of Psychology, University of Kent; 35Department of Psychology, TOBB
University of Economics and Technology; and 36Department of Psychology, Fundación Universitaria Konrad Lorenz
Abstract
What motives do people prioritize in their social lives? Historically, social psychologists, especially those adopting an
evolutionary perspective, have devoted a great deal of research attention to sexual attraction and romantic-partner
choice (mate seeking). Research on long-term familial bonds (mate retention and kin care) has been less thoroughly
Corresponding Authors:
Douglas T. Kenrick, Department of Psychology, Arizona State University, 950 S. McAllister St., Tempe, AZ 85287-1104
E-mail: douglas.kenrick@asu.edu
Michael E. W. Varnum, Department of Psychology, Arizona State University, 950 S. McAllister St., Tempe, AZ 85287-1104
E-mail: mvarnum@asu.edu174 Ko et al. connected to relevant comparative and evolutionary work on other species, and in the case of kin care, these bonds have been less well researched. Examining varied sources of data from 27 societies around the world, we found that people generally view familial motives as primary in importance and mate-seeking motives as relatively low in importance. Compared with other groups, college students, single people, and men place relatively higher emphasis on mate seeking, but even those samples rated kin-care motives as more important. Furthermore, motives linked to long- term familial bonds are positively associated with psychological well-being, but mate-seeking motives are associated with anxiety and depression. We address theoretical and empirical reasons why there has been extensive research on mate seeking and why people prioritize goals related to long-term familial bonds over mating goals. Reallocating relatively greater research effort toward long-term familial relationships would likely yield many interesting new findings relevant to everyday people’s highest social priorities. Keywords interpersonal relations, family, evolutionary psychology, motivation, goals, reward Which aspects of their social lives do people think are From the perspective of evolution by natural selec- most important? Which domains of their social lives do tion, reproduction is critical for all living organisms. people associate with meaningful and fulfilling lives? Obviously, one essential aspect of reproduction is find- What makes people happy as opposed to miserable? ing a sexual partner. If they were successful at nothing What are the most important social rules about? Along else, every one of our ancestors was successful at find- with a number of colleagues, we have been delving ing at least one sexual partner. into questions involving fundamental human social For decades preceding the advent of an evolutionary motives over the past 2 decades (Kenrick, Griskevicius, perspective in social psychology, researchers have Neuberg, & Schaller, 2010; Kenrick, Li, & Butner, 2003; devoted substantial attention to various facets of sexual Kenrick, Neuberg, Griskevicius, Becker, & Schaller, 2010; attraction and romantic-partner choice (Berscheid, Maner et al., 2005; Neel, Kenrick, White, & Neuberg, Dion, Walster, & Walster, 1971; Byrne, 1976; Byrne, 2016). We use the term fundamental very specifically Ervin, & Lamberth, 1970; Dutton & Aron, 1974; Snyder, here—to mean domain-specific motives that are likely Tanke, & Berscheid, 1977). Research in this area has to have been linked to universal and recurrent problems revealed a great deal about which characteristics people and opportunities faced by our human ancestors find desirable in romantic/sexual partners, for example, (Kenrick, Griskevicius, et al., 2010; Schaller, Kenrick, as well as how those characteristics vary for men versus Neel, & Neuberg, 2017; Schaller, Neuberg, Griskevicius, women and for those seeking short-term versus long- & Kenrick, 2010). Recently, we began investigating how term partners (e.g., Buss, 1994; Cunningham, Druen, & these fundamental social motives might be associated Barbee, 1997; Feingold, 1992; Fletcher et al., 1999; with psychological well-being and self-actualization Gangestad & Simpson, 2000; N. P. Li, Bailey, Kenrick, (Kenrick & Krems, 2018; Ko & Suh, 2019; Krems, Kenrick, & Linsenmeier, 2002; H. K. Perilloux, Webster, & Gaulin, & Neel, 2017) and how such associations might hold 2010; Reis et al., 1982; Simpson, Gangestad, Christensen, across different societies around the world (Varnum, & Leck, 1999). A glance at almost any modern social- Kenrick, Pick, & Ko, 2019). psychology textbook will likely reveal a chapter on In considering the question of which social motives attraction, with much of that chapter focused on sexual are fundamental to human beings, our research has been attraction and romantic love (e.g., Gilovich, Keltner, guided by ideas from evolutionary life-history theory Chen, & Nisbett, 2016; Kenrick, Neuberg, Cialdini, & (e.g., Kenrick, Griskevicius, et al., 2010). Given that Lundberg-Kenrick, 2019; Myers, 2013). In such text- humans’ social motives have been shaped by recurrent books, the discussion of sexual attraction is almost adaptive challenges and opportunities, the fundamental certain to include a consideration of the evolutionary social-motives approach focuses on qualitatively distinct significance of the various features that people find social goals that humans pursue to manage those chal- desirable. Indeed, if an evolutionary perspective is lenges and opportunities. The strategies involved in suc- included anywhere in a social-psychology textbook, it cessfully cooperating with friends, romantic partners, is most likely to be found in the discussion of sexual and family members, for example, are likely to be dif- attraction. ferent in important ways (Kenrick, Sundie, & Kurzban, In light of the importance that evolutionary social 2008). psychologists (including the corresponding author of
Family Matters 175
Table 1. Fundamental Social Motives Inventory: Selected Items
Subscale Sample item
Self-protection I think a lot about how to stay safe from dangerous people.
Disease avoidance I avoid people who might have a contagious illness.
Affiliation (group) I like being part of a team.
Affiliation (independence) I would prefer to spend time alone rather than being surrounded by other people.
Affiliation (exclusion concern) I would be extremely hurt if a friend excluded me.
Status seeking I want to be in a position of leadership.
Mate seeking I am interested in finding a new romantic/sexual partner.
Breakup concern I often think about whether my partner will leave me.
Mate retention It is important to me that my partner is emotionally loyal to me.
Kin care (family) Caring for family members is important to me.
Kin care (children) I like to spend time with my children.
Note: Subscale and sample items are from Neel, Kenrick, White, and Neuberg (2016).
this article) have placed on sexual attraction and pattern stood out. As shown on the lower half of the
romantic-partner choice, we were a bit surprised by a graph, people overwhelmingly ranked mate seeking as
pattern we observed in several of the data sets we have the least important motive (Fig. 1b, red bar). The upper
been collecting on the topic of fundamental social half of the graph, by contrast, indicates that the goals
motives. As one example, consider the results of a study linked to long-term familial bonds (mate retention and
in which 3,214 adults were asked to rate which social kin care; Fig. 1a, blue bars) stood out as the most
goals were most important in their lives (Ko, Krems, important goals in people’s current lives. Mate seeking,
Peysha, & Kenrick, 2019). These participants were first by contrast, was rarely chosen as most important (Fig.
asked to complete the Fundamental Social Motives 1a, red bar; see the Supplemental Material for the full
Inventory (Neel et al., 2016). Table 1 presents examples rank order of each of the goals).
of items on that scale. At first glance, there certainly seems to be some
After completing the Fundamental Social Motives discrepancy between the goals given priority by par-
Inventory, participants were shown a list of 10 different ticipants in this sample and the relative priorities that
goals roughly corresponding to those same motives, social and evolutionary psychologists have historically
and they were asked to rank those goals according to given to these different topics (e.g., Daly, Salmon, &
their importance in their current lives (using summary Wilson, 1997; Webster, Jonason, & Schember, 2009).
labels as shown in Table 2). Figure 1 shows the goals Figure 2 shows a word cloud from an article titled, “Hot
that participants ranked as highest in personal impor- topics and popular papers in evolutionary psychology”
tance (on the top; Fig. 1a) and those that they ranked as (Webster et al., 2009). The biggest topic is sex and the
lowest in personal importance (on the bottom; Fig. 1b). next is attractiveness.
When we examined how people ranked the impor- In a completely different research area—the study of
tance of these different goals in their lives, one striking positive emotions—authors of a recent review concluded
Table 2. List of Goals Participants Were Asked to Rank in Terms of Their Importance to Them
in Their Current Lives
Goal Description
Self-protection Staying safe from dangerous people
Disease avoidance Avoiding disease
Affiliation (group) Being part of a group or team
Affiliation Spending time with friends
Affiliation (exclusion concern) Being accepted and included
Status seeking Having others respect my status
Mate seeking Finding a new romantic/sexual partner
Mate retention Staying with a romantic/sexual partner long term
Kin care (family) Spending time with and helping parents, siblings, or other relatives
Kin care (children) Taking care of a child/children176 Ko et al.
a high coverage of sexual attraction compared with lower
coverage of long-term familial relationships (e.g.,
Most Important Goals Anderson et al., 2010; Griskevicius, Cialdini, & Kenrick,
2006; Kenrick & Cialdini, 1977; Kenrick & Gutierres,
30 1980; Kenrick, Gutierres, & Goldberg, 1989; Kenrick &
Keefe, 1992; Kenrick, Stringfield, Wagenhals, Dahl, &
Ransdell, 1980; N. P. Li & Kenrick, 2006; Maner et al.,
Percentage
20 2003; A. E. White, Kenrick, & Neuberg, 2013; but see
Ackerman, Kenrick, & Schaller, 2007). Our first thought
was that perhaps the sample whose results are depicted
10 in Figure 1 was not representative of the wider popula-
tion in ways that could uniquely affect the relative
unimportance they placed on mate seeking compared
0 with the especially high importance they placed on
mate retention and kin care. More than two thirds of
b these participants were women who were in a commit-
Least Important Goals ted relationship or had children. The average age of
participants in the sample was 47 years (SD = 11.83).
30 Further, the sample was drawn from a population of
people interested in life coaching.
To investigate the possibility that these results might
be unique to this particular sample, we revisited data
Percentage
20
from several previous studies of fundamental motives
conducted with broader American samples and also
10 examined more recent cross-cultural samples from 27
different countries. Figure 3a presents the means for
the different motives from the Amazon Mechanical Turk
0 (MTurk) sample used in the original study of individual
differences in fundamental social motives (Neel et al.,
2016; N = 1,560, mean age = 34.25 years, SD = 12.59).
.)
Affi Avo ion
n ( ce
Affi up)
n
ng
Kin Re ng
Kin are tion
(Ch ily)
)
ren
tus lus
tio liatio
lia idan
i
i
am
ct
Ma eek
k
o
n
ild
Sta (Exc
Ma See
Gr
Once again, it is noteworthy how relatively low mate
ea ote
e
F
t
S
(
Dis lf-Pr
te
seeking was rated (red) and how relatively high mate-
n
tio
te
re
se
C
Ca
Se
lia
retention and kin-care motives were (blue). People in
Affi
this broader sample again tended to score higher on
Fig. 1. Most important and least important goals. A sample of 3,214 mate-retention and kin-care motivations than on mate-
adults rated goals as (a) most important (i.e., top two goals) or (b) seeking and breakup-concern motivations. Breakup
least important (i.e., bottom two goals) in their current lives (Ko, concern was not measured in the life-coaching sample
Krems, Peysha, & Kenrick, 2019; for the complete set of rankings,
see Fig. S1 in the Supplemental Material available online). The red
and therefore was not included in the ranking of
bars indicate the mate-seeking goal, and the blue bars indicate goals motives shown in Figure 1, but we have highlighted it
linked to long-term familial bonds. here because both mate seeking and breakup concern
might be regarded as motives that are active when one
is in an uncertain or unfulfilled state with regard to a
that sexual desire has received a great deal of research long-term relationship. By contrast, mate-retention and
investigation, whereas nurturant love and attachment kin-care motives are likely to be active when one is in
love (emotions linked to kin care and mate retention) a long-term relationship that is perceived as stable,
have been less well studied (Shiota et al., 2017). committed, or permanent (in the case of kin relation-
This pattern captured our attention because mem- ships, particularly).
bers of our team have published articles in mainstream Figure 3b depicts the analogous results for a much
social-psychology and evolutionary-psychology jour- broader sample of 7,296 people in 27 countries (mean
nals and have authored a social-psychology textbook, age = 24.03 years, SD = 8.14; Varnum et al., 2019). Within
and the ratio of our own coverage of mate seeking as each of the 27 societies, we found the same pattern of
opposed to kin care and mate retention has certainly results (Fig. 3c): People around the globe rate kin-care
been in line with the historical biases of many other and mate-retention motives higher than they rate mate-
evolutionarily oriented social psychologists—relatively seeking motives.Family Matters 177
Fig. 2. Word cloud from Webster, Jonason, and Schember (2009). Republished under a CC BY-NC
3.0 license (https://creativecommons.org/licenses/by-nc/3.0/).
Potential Moderators and Boundary (children; for the Neel et al. data, d = 0.28; for the
Conditions? Sex, Age, and Relationship Varnum et al. data, d = 0.18) than did men. This is
consistent with other social-psychological findings
Status
(Buckels et al., 2015; Hofer, Buckels, White, Beall, &
After observing similar results across several diverse sam- Schaller, 2018; Neel et al., 2016). Nevertheless, those
ples, we considered several possible factors that might sex differences, though statistically reliable, appear
reverse the general pattern, leading some people to rate small in this context, because they are dwarfed by the
mate-seeking motives relatively higher than motives overall differences between mate-seeking and familial-
related to long-term familial bonds. Three obvious can- bonding motives. The effect sizes were indeed quite
didates were participants’ sex, their age, and whether large for paired comparisons between mate seeking and
they were single or in a committed relationship. kin care (family; for the Neel et al. data, d = 1.78; for
the Varnum et al. data, d = 1.54) and between mate
seeking and kin care (children; for the Neel et al. data,
Sex
d = 3.21; for the Varnum et al. data, d = 1.67).
A great deal of research on sexual attraction and mate
seeking has revealed robust sex differences in these
motivational domains. On average, men tend to express
College students
relatively more interest in casual sexual relationships College students have historically been the main popu-
and women tend to express relatively more interest in lation studied by psychologists (Henrich, Heine, &
long-term committed relationships (Buss & Schmitt, Norenzayan, 2010). This generalization is certainly true
1993; Clark & Hatfield, 1989; Gangestad & Simpson, for studies of sexual-attraction and mating motivation
2000; Kenrick, Groth, Trost, & Sadalla, 1993; N. P. Li (e.g., Griskevicius et al., 2006; Griskevicius, Goldstein,
et al., 2002; Schmitt, 2005). Figure 4 shows the focal et al., 2009; Griskevicius, Tybur, et al., 2009; Griskevicius
mate-seeking and breakup-concern goals (red) and et al., 2007; Sundie et al., 2011). However, college stu-
familial-bonds goals (blue) separately for men (no dents may differ from the larger population because
shading) and women (yellow shading) from the results they are at a life stage at which seeking a mate is espe-
of the Neel et al. (2016) MTurk sample (Fig. 4a) and cially important. Indeed, when we examined data from
from the Varnum et al. (2019) sample of 27 different an independent sample of American undergraduate
countries (Fig. 4b). In both studies, men were signifi- students (N = 497, mean age = 19.15 years, SD = 1.50;
cantly higher on mate-seeking motivation than were Ko & Barlev, 2019; Fig. 5), the students’ scores on the
women (for the Neel et al. data, d = 0.55; for the Varnum mate-seeking motive were significantly higher than
et al. data, d = 0.24), which is consistent with an abun- those seen in the other samples. If one compares the
dance of previous findings. Furthermore, women scored results in Figure 5 to those in Figure 3, one can see that
significantly higher on mate retention (for the Neel mate seeking is a stronger motivation in this college
et al. data, d = 0.41; for the Varnum et al. data, sample than among the more representative and, on
d = 0.31), kin care (family; for the Neel et al. data, d = average, older samples previously discussed. Neverthe-
0.47; for the Varnum et al. data, d = 0.35), and kin care less, even though mate seeking increased in importance178 Ko et al.
a b
MTurk Across 27 Countries
6 6
Self-Rated Motivations
Self-Rated Motivations
4 4
2 2
Affi Avo ion
Affi ion ( ce
Affi tion up)
Sta (Exc .)
.)
Br te S ing
Ma Con g
Kin Ret rn
Kin are tion
(Ch ily)
)
Affi Avo ion
Affi ion ( ce
Affi tion up)
Sta (Exc .)
.)
Br te S ing
g
Kin Re rn
Kin are tion
(Ch ily)
)
ren
ren
ku eekin
ku ekin
p
tus lus
p
tus lus
ce
ce
n
n
tio de
tio de
Ca Fam
m
ct
ct
Ma eek
Ma eek
lia Gro
ro
lia ida
lia ida
n
C ten
ild
ild
Ma on
Ca (Fa
ea ote
ea ote
e
lia (In
lia (In
G
e
S
-S
pC
(
Dis lf-Pr
Dis lf-Pr
p
n
n
te
te
re
re
se
t
se
t
C
lia
Se
Se
ea
ea
c
Australia Austria Bolivia Brazil Bulgaria Canada Chile
6
4
2
China Colombia Czech Republic Germany Hong Kong India Italy
6
Self-Rated Motivations
4
2
Japan New Zealand Pakistan Romania Russia South Korea Spain
6
4
2
Thailand Turkey Uganda Ukraine United Kingdom United States
MA
MRAT
KCT
AF I
AF S
G
X
KC F
O
C
MRB
AF
ST
DI
SP
6
4
2
MA
MRAT
MA
MRAT
MAA
MR T
T
KCT
KCT
AF I
AF I
AF I
AF S
AF S
AF S
X
KC F
G
X
KC F
G
X
KC F
O
G
C
O
C
O
C
MRB
MRB
MRB
MA
MA
MRAT
MRAT
MA
MRAT
KCT
KCT
AF I
AF I
KCT
AF I
AF S
DIS
DIS
G
X
KC F
G
X
KC F
O
C
O
C
G
X
KC F
O
C
MRB
MRB
MRB
AF
AF
AF
AF
AF
AF
ST
ST
ST
KC
DI
DI
DI
ST
ST
ST
SP
SP
SP
DI
AF
AF
SP
SP
SP
Fundamental Social Motives
Fig. 3. Fundamental Social Motive Inventory results. The plot in (a) shows results from an Amazon Mechanical Turk sample (N = 1,560;
Neel et al., 2016). The plot in (b) shows results from ongoing global data collection from 27 countries (N = 7,296; Varnum, Kenrick, Pick,
& Ko, 2019) aggregated across all countries. The plots in (c) show the same data broken down by country. Breakup-concern and mate-
retention questions were asked only of participants in relationships. Kin-care (children) questions were asked only of participants who
had children. For the box-and-whiskers plots, the horizontal bar and circle within each box represent the median and mean, respectively.
The top and bottom of the box represent the interquartile range, and the ends of the whiskers represent the maximum (top) and minimum
(bottom) values. The dashed line indicates the scale midpoint. Red plots show mate-seeking and breakup-concern goals, and blue plots
show goals linked to long-term familial bonds. SPO = self-protection; DIS = disease avoidance; AFG = affiliation (group); AFI = affiliation
(independence); AFX = affiliation (exclusion concern); STA = status; MAT = mate seeking; MRB = breakup concern; MRT = mate retention;
KCF = kin care (family); and KCC = kin care (children).Family Matters 179
a b
MTurk Across 27 Countries
6 6
Self-Rated Motivations
Self-Rated Motivations
4 4
2 2
Mate Breakup Mate Kin Care Kin Care Mate Breakup Mate Kin Care Kin Care
Seeking Concern Retention (Family) (Children) Seeking Concern Retention (Family) (Children)
Fig. 4. Box-and-whiskers plots of self-rated motivations related to mate seeking and breakup concern (red) and familial bonds (blue),
separately for female (yellow shading) and male (no shading) participants. The horizontal bar and circle within each box represent the
median and mean, respectively. The top and bottom of the box represent the interquartile range, and the ends of the whiskers represent
the maximum (top) and minimum (bottom) values. The dashed line indicates the scale midpoint. Data for (a) are from Neel, Kenrick,
White, and Neuberg’s (2016) focal study and data for (b) are from an ongoing global data collection from 27 countries (Varnum, Kenrick,
Pick, & Ko, 2019).
in this undergraduate sample, kin care (family) and a comparable level to several other motives, such as
mate retention are still much stronger motivations than self-protection and various aspects of affiliation, and
mate seeking (ds = 1.52 and 3.55, respectively). Kin higher than disease avoidance. Of course, it makes
care (children) was not relevant here, because the
majority of these college students did not have children,
and those items were therefore not administered to this
sample.
6
Self-Rated Motivations
Relationship status
Of course, many college students and older adults are 4
already in a long-term relationship, and those in rela-
tionships are likely to be less concerned with seeking
new partners. Perhaps the most relevant life-history 2
comparison would be to compare the data for people
in a long-term relationship with data for people who
are not. To address this possibility, we collapsed data
Affi Avo on
Affi on (G e
Affi tion up)
n ep.)
)
Br te Se g
g
Kin Ret n
re tion
ly)
tus lus.
c
n
ku ekin
er
across the various samples mentioned so far (total N =
mi
lia idan
cti
Ma eeki
ro
Ma Conc
n
lia (Ind
Sta (Exc
(Fa
ea ote
e
S
12,046) and examined the strength of the various fun-
Dis lf-Pr
p
te
tio
ti
Ca
se
damental motives as a function of participants’ relation-
lia
Se
ea
ship status (Fig. 6).
We indeed observed sizeable differences in mate-
Fig. 5. Fundamental Social Motive Inventory results for undergradu-
seeking motivation between participants who were in
ate students at a large state university (N = 497; Ko & Barlev, 2019).
a committed relationship (green shading) compared Box-and-whiskers plot shows self-rated motivations related to mate
with those who were not (no shading; d = 1.21). For seeking and breakup concern (red) and familial bonds (blue). The
those in a committed relationship, mate-seeking motiva- horizontal bar and circle within each box represent the median and
mean, respectively. The top and bottom of the box represent the
tion was well below the midpoint of the scale, whereas interquartile range, and the ends of the whiskers represent the maxi-
for those who were not in a long-term relationship, mum (top) and minimum (bottom) values. The dashed line indicates
mate-seeking was above the midpoint of the scale—at the scale midpoint.180 Ko et al.
Self-Rated Motivations eminent sense that mate seeking is a more important
2 4 6 motivation for those who are not in a relationship. And
yet it is noteworthy that even among single people,
kin-care (family) motivation was still substantially
Self- higher than mate-seeking motivation (d = 1.03).
Protection
Positivity Versus Negativity of Mate
Disease Seeking and Family Values
Avoidance
A plausible concern about the findings presented here
is that the Fundamental Social Motives Inventory
Affiliation might contain items written such that mating items
(Group) are less appealing to endorse than familial-bonds
items. However, the results for the study shown in
Figure 1 were obtained using a different method than
Affiliation the results for the studies shown in Figures 3 through
(Indep.) 5 (which used the Fundamental Social Motives Inven-
tory), yet they show the same pattern. For that first
study, people were asked to rank brief descriptions
Affiliation of the different goals according to their personal
(Exclus.) importance (using the summary terms shown in Table
2). Furthermore, and lending support to the notion
that people may be accurately reflecting their moti-
Status vational priorities, the results depicted in Figure 6
Seeking indicate that, as expected, people who are single do
indeed report levels of mate seeking equivalent to
several other motives.
Mate Perhaps, on the other side of the equation, familial-
Seeking bonds motives are simply strongly associated with gen-
eral positivity and social desirability. That makes some
sense, but other data sets we will discuss below suggest
Breakup that the relationship between those motives and positiv-
Concern ity is not quite so simple.
Mate Psychological well-being and the
Retention fundamental social motives
Figure 7 depicts results from a study in which partici-
Kin Care pants were asked what they would be doing “right now”
(Family) if they were pursuing (a) “eudaimonic well-being,
which is about finding meaning and purpose in life”;
(b) “self-actualization, which is about fully realizing
Kin Care your own potential”; and (c) “hedonic well-being,
(Children) which is about maximizing the amount of pleasure in
your life (and minimizing the amount of pain)” (Krems
et al., 2017). Those participants (N = 565, mean age =
Fig. 6. Fundamental Social Motive Inventory results from all participants 37.97 years, SD = 13.00) were then asked to consider
who provided data depicted in Figures 1, 3, and 5, presented separately the extent to which their answers reflected the different
for participants who were in a long-term relationship (green shading; n = motives (using summary descriptions similar to those
6,869) and participants who were not (no shading; n = 5,177). Breakup- shown in Table 2, except that the different facets of
concern and mate-retention items were not relevant to individuals not
in relationships, and such individuals were asked not to complete them. affiliation and kin care were not distinguished).
The vertical bar and circle within each box represent the median and With regard to meaning in life (eudaimonic well-
mean, respectively. The left and right sides of the box represent the being; Fig. 7a), mate retention and kin care were again
interquartile range, and the ends of the whiskers represent the maximum
rated more highly than mate seeking, but the overall
(right) and minimum (left) values. The dashed line indicates the scale
midpoint. Red plots show mate-seeking and breakup-concern goals, and pattern for other motives was rather different from that
blue plots show goals linked to long-term familial bonds. presented in our first six data figures. Across the threeFamily Matters 181
a types of well-being, affiliation was seen as substantially
higher in importance than was mate retention, for exam-
Eudaimonic Well-Being
ple. With regard to self-actualization (Fig. 7b), there was
5
another distinct pattern: Mate seeking was again rated
as relatively irrelevant, but status motives rose to the
top in importance, and neither mate retention nor kin
4
Reflected Motivations
care were seen as being of paramount importance. For
hedonic well-being (Fig. 7c), there was yet another
distinct pattern: Mate seeking rose from its position of
3
relative unimportance and was here rated as equivalent
in importance to mate-retention and kin-care motives.
Kin care’s lower relevance to hedonic well-being
2
compared with eudaemonic well-being mirrors other
findings that parents experience relatively low moment-
to-moment positivity in contact with their children but
1
an overall higher level of happiness and meaning in
b life (e.g., Kahneman, Krueger, Schkade, Schwarz, &
Stone, 2004; Nelson, Kushlev, English, Dunn, &
Self-Actualization Lyubomirsky, 2013). Thus, there is certainly not a sim-
5 ple positivity/negativity bias in the mate-seeking and
familial-bonds motives across the different types of
psychological well-being.
4
Reflected Motivations
In another study (Varnum & Kenrick, 2019), we
explored the links between scores on fundamental
social motives and several measures of psychological
3 well-being and distress, such as life satisfaction (Diener,
Emmons, Larsen, & Griffin, 1985), depression (Baron,
Davies, & Lund, 2017), and anxiety (Spitzer, Kroenke,
2 Williams, & Löwe, 2006) in an MTurk sample (N = 263,
mean age = 34.87 years, SD = 11.21; see Fig. 8). People
who reported higher levels of kin-care (family) and
1 kin-care (children) motivation were more satisfied with
their lives (rs = .22 and .29, respectively, ps < .001; Fig. 8a).
c They reported being less depressed (rs = −.33 and −.39,
Hedonic Well-Being respectively, ps < .001; Fig. 8b), and less anxious (r =
5 −.27, p < .001, and r = −.21, p = .01, respectively;
Fig. 8c). In contrast, people who reported high levels
of mate-seeking motivation were less satisfied with their
4 lives (r = −.22, p < .001) while being more depressed
Reflected Motivations
(r = .31, p < .001) and more anxious (r = .21, p = .001).
This pattern may be associated with feeling lonely or
3 experiencing difficulties finding a mate. Likewise, peo-
ple who reported higher levels of breakup concern
2
Fig. 7. Results from Study 2 in Krems, Kenrick, and Neel (2017).
1 These results show which motives participants said they would be
focused on “right now” if they were pursuing one of three different
types of well-being: (a) eudaimonic well-being (i.e., finding mean-
n
Affi ce
tus tion
ng
Re ng
Kin n
re
tio
tio
Ca
an
Ma eeki
i
ing and purpose in life), (b) self-actualization (i.e., fully realizing
Ma Seek
tec
lia
ten
oid
their own potential), or (c) hedonic well-being (i.e., maximizing
S
Pro
Av
te
pleasure and minimizing pain). The red bars indicate mate-seeking
lf-
te
se
Sta
Se
and breakup-concern goals, and blue bars indicate goals linked to
ea
Dis
long-term familial bonds.182 Ko et al.
were also less satisfied with their lives (r = −.19, p =
a .007), more depressed (r = .57, p < .001), and more
Life Satisfaction anxious (r = .54, p < .001). Thus, higher kin-care moti-
.6 vation is associated with feelings of psychological well-
being, whereas being concerned with finding or
keeping a mate is associated with relatively more dis-
.3 tress and lower life satisfaction.
Correlation
.0 Social rules and fundamental
social motives
Another study found yet a different ordering of the
−.3
importance of different social motives but still found a
similar pattern with regard to long-term familial goals
−.6
compared with mating-related goals. In that study, con-
cerned with the formal and informal rules that govern
people’s social lives, participants were asked about the
b degree to which they thought important social rules
Depression were relevant for achieving goals associated with fun-
.6 damental social motives (Kwon, Barlev, Kenrick, &
Varnum, 2019). Participants in this study first completed
the Fundamental Social Motives Inventory and then
.3 were asked to free-list 10 specific rules, guidelines, and/
or principles that were important to them. Afterward,
Correlation
they saw short descriptors capturing the goals associated
.0 with each fundamental social motive and were asked to
rate each rule on how relevant it was for achieving each
goal (0 = least relevant; 100 = most relevant).
−.3 Across each participant’s 10 rules, we aggregated their
ratings of the rules’ relevance to each fundamental social
motive, to provide a general measure of what the par-
−.6 ticipant perceived those rules to be for. As shown in
Figure 9, an MTurk sample (N = 139, mean age = 35.68
c years, SD = 10.96) rated their self-generated important
Anxiety rules to be more relevant to kin care than to mate seek-
.6 ing (d = 0.37, p < .001). A younger, undergraduate sam-
ple (N = 161, mean age = 19.04 years, SD = 1.34) rated
their rules to be most relevant to affiliation, but kin care
.3 was still rated as the second-most-relevant motive. Com-
pared with the MTurk sample, college students also rated
Correlation
the rules to be slightly more relevant to mate seeking,
.0 so that the difference in relevance between mate seeking
and kin care was smaller (d = 0.15, p = .034; Fig. 9). The
general pattern of these rankings did not change when
−.3 we examined the ratings separately for men versus
women, nor separately for single people versus those in
a committed relationship.
−.6
ild )
)
Kin te R onc g
Kin Ca ete ern
Ca re (F ntion
tu xc .)
Ma s Se lus.)
k e g
Affi iatio oida n
Affi liatio (Gr ce
tio In )
(Ch ily
ren
lia n ( oup
ea S in
Ma up C ekin
l v io
Sta n (E dep
n n
Fig. 8. Results from an Amazon Mechanical Turk sample (N = 263;
re am
Affi se A tect
Br te ek
Varnum & Kenrick, 2019). The graphs show the relationships between
ea Pro
fundamental social motives and (a) life satisfaction, (b) depression,
Dis Self-
and (c) anxiety. The red bars indicate mate-seeking and breakup-
concern goals, and blue bars indicate goals linked to long-term
familial bonds.Family Matters 183
a b
MTurk Undergraduates
100 100
75 75
Relevance Rating
Relevance Rating
50 50
25 25
0 0
n
ce
n
i ng
i ng
n
re
n
ce
n
i ng
i ng
n
re
tio
tio
tio
tio
tio
tio
Ca
Ca
an
an
ek
ek
ek
ek
tec
lia
ten
tec
lia
ten
oid
oid
Kin
Kin
Se
Se
Se
Se
Affi
Affi
Pro
Pro
Re
Re
Av
Av
tus
te
tus
te
lf-
lf-
te
te
Ma
Ma
se
se
Sta
Sta
Ma
Ma
Se
Se
ea
ea
Dis
Dis
Fig. 9. Results from Kwon, Barlev, Kenrick, and Varnum (2019). Mean participant ratings of (A) Amazon Mechanical Turk workers
(n = 139) and (b) undergraduates (n = 161) of the degree to which their self-generated important social rules were relevant to each of
the fundamental social motives. The horizontal bar and circle within each box represent the median and mean, respectively. The top and
bottom of the box represent the interquartile range, and the ends of the whiskers represent the maximum (top) and minimum (bottom)
values. The dashed line indicates the scale midpoint. Red plots show mate-seeking and breakup-concern goals, and blue plots show
goals linked to long-term familial bonds.
It is worth pointing out that participants were not motives, are more likely to be seen as related to the
asked to rate how relevant their self-generated rules pursuit of a meaningful and fulfilling life; (d) higher
were for the pursuit of their own personal goals and motivation for familial-bonds goals is associated with
that participants did not appear to be merely projecting better psychological well-being, whereas higher motiva-
their own motivations onto these rules. The correla- tion for mate-seeking goals is associated with greater
tions between an individual’s scores on each funda- distress; and (e) mate retention and kin care are seen
mental motive with his or her corresponding rating of as linked to the social rules that people find important
rule relevance to that motive were fairly modest and in their lives. Mate seeking is also prominently linked
inconsistent. These correlations suggest that this mea- to important social rules, but more so for college stu-
sure of the perceived function of social rules is not dents than for older adults, and to a lesser extent than
simply another way of measuring which motives are kin care.
important to each individual. One potential argument for why family-related
motives might appear stronger or more relevant than
those related to mate seeking is that social desirability
Interim Summary or some other artifact explains the pattern we observed
To summarize thus far, using qualitatively different mea- in the various data sets discussed in the present work.
sures and questionnaires, we found consistent and con- Although we cannot definitively rule out this possibility,
verging patterns in samples varying in sex, age, there are several reasons to believe this is not likely the
relationship status, and cultural background, which case. First, in all of the studies discussed here, partici-
suggests that (a) in their current lives, people place pants were anonymous and had a reasonable expecta-
substantially lower importance on mate-seeking motives tion of privacy. Second, we observed the same pattern
compared with motives linked to long-term familial (higher familial-bonds versus mate-seeking motives)
bonds; (b) people report lower overall levels of mate- across a variety of different measurement instruments
seeking motivation compared with motivation linked and paradigms, including the Fundamental Social
to long-term familial bonds; (c) people’s mate-retention Motives Inventory (Neel et al., 2016; Varnum et al.,
and kin-care motives, compared with mate-seeking 2019), ranking of the fundamental motive domains by184 Ko et al.
importance (Ko et al., 2019), and ratings of self-generated connect those goals to ultimate inclusive fitness, for
rules’ relevance to accomplishing various fundamental example, but they can tell you if they spend hours a
motives (Kwon et al., 2019). day worrying about status.
Third, we also observed the same general pattern Thus, taken together, we suspect that social desir-
across 27 societies, across student and nonstudent sam- ability, potential idiosyncrasies in the Fundamental
ples, across men and women, and when comparing Social Movies Inventory, or other such potential artifacts
people who were single versus people in a committed are not likely to account for the general pattern of
relationship. Given that societies differ quite substan- results observed across these diverse data sets. We think
tially in sociosexuality (Schmitt, 2005), as do different it is worth seriously entertaining the possibility that
demographic groups within a given society, if social people in all of these different samples are telling us
desirability was the major determinant of the results, something about their actual motivational priorities.
then we would expect the overall pattern not to repli- That being said, it may be worthwhile to assess the
cate across these groups. Yet it does, quite consistently. relative importance or salience of familial-bonds and
Fourth, it is not the case that mate seeking is always mate-seeking motives using implicit or behavioral mea-
the lowest among the motives. In fact, collapsing across sures in future research.
samples using the Fundamental Social Movies Inventory
(Neel et al., 2016), we find that mate seeking is rated Why Have Social and Evolutionary
as highly as several other motives among single people, Psychologists Focused Relatively Less
that mate seeking is the fourth most relevant motive Attention on Kin Relations Compared
dimension (out of seven) of self-generated social rules
(Kwon et al., 2019), and that when asked which types
With Sex?
of goal pursuit are linked to different types of well- In 1997, Daly et al. argued that kinship is a central
being, people indicated that mate seeking and familial aspect of social relationships around the world but that
motives are of comparable importance for the pursuit it had been largely ignored by social psychologists.
of hedonic well-being. Finally, mate retention is not Indeed, they labeled this a “conceptual hole” in social
seen as particularly important to either eudaimonic psychology. As noted above, a more recent review of
well-being or self-actualization (Krems et al., 2017). research on the topic of positive emotions also found
Note that there are a plethora of findings indicating that that sexual desire has received a great deal of research
people are not generally unwilling to admit to thinking attention, whereas nurturant love and attachment love
about sexual or romantic motives. For example, the (both connected to familial bonds) were still relatively
average college man or woman is willing to admit to less explored (Shiota et al., 2017). Several researchers
having fantasies about sex several times each day (Bau- who have adopted an evolutionary perspective have con-
meister, Catanese, & Vohs, 2001; Ellis & Symons, 1990). ducted studies on various aspects of kinship (Ackerman
Aligned with concerns about social desirability are et al., 2007; Laham, Gonsalkorale, & von Hippel, 2005;
more general concerns about how self-report methods Lieberman, 2009; Lieberman, Tooby, & Cosmides, 2007;
reflect on deeper “why” questions of people’s motiva- Salmon & Shackelford, 2007). Nevertheless, there has
tions. It seems unlikely that people can be trusted to been much more emphasis on sexual attraction and
report on the ultimate “why” of the goals about which mate choice (Webster et al., 2009). This is worth noting,
they are obsessing. But they can report on “what”—in given that kin selection and inclusive fitness are argu-
the sense of what preoccupies them on a daily basis. ably the most foundational concepts of modern evolu-
Of course, there are still the usual problems of self- tionary approaches to behavior (Abbot et al., 2011;
report—for example, honesty and self-delusion. How- Dawkins, 1979; Eberhard, 1975; Hamilton, 1964; Smith,
ever, in a classic study of human motivation, men put 1964).
on a starvation diet began to fantasize about food con- There are several explanations for the ample empiri-
tinually (Keys, Brožek, Henschel, Mickelsen, & Taylor, cal and theoretical attention toward sexual attraction
1950). Further, other research shows that undergraduate and romantic-partner choice. For one thing, mate acqui-
college students admit to thinking about sex multiple sition is not only a necessary condition for reproduc-
times every day (Baumeister et al., 2001; Ellis & Symons, tion, but also the most causally proximate variable in
1990). Therefore, it is reasonable to trust that people producing offspring. Of the myriad conditions that a
can accurately report on the “what” of their daily moti- sexually reproducing organism must meet to achieve
vations, even if they do not think about or even under- reproductive success, it is perhaps most evident that the
stand how those immediate phenomenological goals production of offspring requires copulation. For many
are connected. Men might not connect their desire for mammals, including humans, a single reproductive epi-
status to mate-acquisition goals and are unlikely to sode could be sufficient to produce offspring—in otherFamily Matters 185
words, copies of one’s genes. And although parental compared with other motives throughout one’s life
investment in offspring greatly facilitates their reproduc- course, it did steadily increase from the ages of 18 to
tive success, even when investment is lacking, offspring 30 years. Hence, there are several factors that would
may still survive. For example, although survivorship lead researchers working on college campuses to view
increases with parental investment (Geary, 2000, 2005), mate seeking as especially important.
in many animal species there is little to no parental care; Finally, from a methodological standpoint, studying
instead, much effort is devoted to mating competition individual judgments is much easier than studying
and attraction. Therefore, mate acquisition may hold a dyads or family groups. Although much social-psycho-
conceptually privileged status with regard to consider- logical theory and research intrinsically involves mul-
ations of reproduction. tiple persons embedded within a social context, dyadic
Another factor contributing to evolutionary theorists’ or group-level data require more complex study designs,
interest in mate selection and sexual behavior is that more expansive data set collections, and more statisti-
comparative evidence of sex differences in mating strat- cally sophisticated data analyses than do individual-level
egies and theoretical concepts of differential parental data (Kenny, Kashy, & Cook, 2006). Sexual attraction
investment and sexual selection allow researchers to and mate preferences are, by contrast, processes that
make strong predictions about humans’ initial mating can be studied at the individual level and that can, in
choices (Buss & Schmitt, 1993; Daly & Wilson, 1983; fact, unfold psychologically within the time frame of a
Kenrick, Sadalla, Groth, & Trost, 1990; Trivers, 1972). laboratory experiment.
In many ways, humans are unique compared with other
animals (communication via complex language, con- Why Family Bonds are Important
struction of complex legal systems, and manufactured
environments, for example). But with regard to repro-
to People’s Everyday Lives
duction, human females share the capacity to bear and From an evolutionary perspective, human psychology
nurse children with all other female mammals, and has been shaped to drive goals and behaviors in ways
differences in parental investment across species have that ultimately resulted in the greatest reproductive fit-
had clear and direct implications for variations in mat- ness for our ancestors. Natural selection favors the allo-
ing strategies. cation of energy in ways that will maximize the greatest
Given the crucial role that mate acquisition plays in inclusive fitness (West & Gardner, 2013). Selective pres-
achieving reproductive success, it makes sense that sures drive individuals to strive to maximize transmis-
much evolved animal behavior can be attributed to the sion of their genes to future generations—directly
motivation to attract members of the opposite sex and through their own reproductive success and indirectly
to maximize the likelihood that one’s offspring will through the reproductive success of other individuals
themselves survive to reproductive age. In fact, research with whom they share genes (their family members).
has linked mate-seeking motivation and strategies to a While attempting to maximize fitness, however, all
wide variety of psychological outcomes, including cre- living organisms face the problem of limited resources.
ativity, risk taking, conformity, financial decisions, and Life-history theory provides a framework that addresses
so forth (e.g., Griskevicius et al., 2006; Y. J. Li, Kenrick, how organisms allocate their limited time and energy
Griskevicius, & Neuberg, 2012; Sundie et al., 2011). to attaining reproductive success, given necessary
There may also be less theoretical reasons why trade-offs (Charnov, 1993; Del Giudice, Gangestad, &
university-based researchers have devoted so much Kaplan, 2015; Kaplan & Gangestad, 2015; Kenrick &
attention to studying sexual attraction and romantic Griskevicius, 2015; Stearns, 1992). For instance, any
choice, and those are related to both Henrich et al.’s energy allocated toward future reproductive opportuni-
(2010) arguments that psychologists commonly draw ties, such as growing and maintaining one’s own bodily
conclusions from White, educated, industrialized, rich, and social capital, is energy that cannot be allocated
and democratic (WEIRD) subject samples, and the cog- toward immediate reproduction. Allocating energy
nitive bias known as the availability heuristic (judging toward producing higher numbers of offspring reduces
the prevalence of a phenomenon by how easily it comes the energy allocated toward enhancing the fitness of
to mind; Schwarz et al., 1991; Tversky & Kahneman, individual offspring, because investing resources in
1973). College undergraduates, who constitute the stu- each additional offspring necessarily reduces the aver-
dents in many researchers’ classes, the assistants in age investment per offspring. In turn, allocating energy
most labs, and the majority of participants in their stud- toward finding additional mating partners reduces the
ies are in the stage of life when acquiring a romantic energy that can be invested in existing offspring.
partner is a salient goal. Indeed, we found that even Cross-species comparisons reveal myriad possible
though mate-seeking motivation was relatively low balances in these fundamental trade-offs. Compared186 Ko et al.
with most other mammals, primates have a slow life pair bonding is associated with better physical and psy-
history characterized by delayed maturity, slower repro- chological well-being for both adults and offspring, per-
duction, fewer offspring, and longer life expectancy haps because it allows greater total investment in shared
( Jones, 2011). Humans, who generally fall at the slow offspring via division of labor and mutual support
end of the spectrum—even among primates—have an (Conroy-Beam, Goetz, & Buss, 2015; Durante, Eastwick,
extended period of juvenile dependence, later age at Finkel, Gangestad, & Simpson, 2016; Finkel & Eastwick,
first reproduction, extensive biparental care, and sup- 2015).
portive child care by older postreproductive individuals Mate seeking is thus only one step on a long pathway
(Kaplan, Hill, Lancaster, & Hurtado, 2000). Given these toward successful reproduction, and that step is typi-
unique features of human life histories, it is not surpris- cally followed by large investments in maintaining a
ing that many fitness-maximizing goals are closely inter- long-term, committed mating relationship. Unlike mate
twined with familial-bonding goals, such as maintaining seeking, which is a goal that can be “checked off” once
a committed mating relationship and provisioning, pro- a person finds a mate, retaining a mate requires con-
tection, and care for one’s family. tinued investment for years and even decades. Indeed,
Children across societies are unable to produce the research suggests that once people form pair bonds,
calories they need to consume until they are approxi- they allocate resources away from seeking new mating
mately 15 to 22 years old. This is relatively late com- partners and toward maintaining their existing relation-
pared with even our nearest phylogenetic relatives, ship (Neel et al., 2016). Compared with single individu-
chimpanzees, who become net producers as early as als, those in a long-term relationship pay less attention
5 years of age (Kaplan et al., 2000). The extraordinary to attractive alternative partners (Miller, 1997) and are
resource demands of human children are solved by more likely than single individuals to downplay the
heavy assistance from parents, older siblings, grandpar- attractiveness of alternatives ( Johnson & Rusbult, 1989;
ents, and often other kin (Hill & Hurtado, 2009; Sear & Lydon, Meana, Sepinwall, Richards, & Mayman, 1999;
Coall, 2011; Sear & Mace, 2008; Snopkowski & Sear, Simpson, Gangestad, & Lerma, 1990) while adopting a
2013). Given the long period of juvenile vulnerability positive bias toward their own partner (Fletcher & Kerr,
and the dependence on the intergenerational transfer 2010).
of resources and skills from kin, the importance of Moreover, men generally contribute heavily toward
these kin is clear. Moreover, extensive cooperative pro- the provisioning of a partner and offspring (Geary &
visioning of young (e.g., alloparenting) eventually Flinn, 2001)—contrary to the general mammalian pat-
increases family members’ inclusive fitness—helping tern in which paternal investment is found in less than
one’s genetic relatives and their offspring survive and 5% of species (Clutton-Brock, 1989). All female mam-
reproduce. Thus, it is unsurprising that one’s degree of mals make an initially higher caloric investment in
genetic relatedness to another person predicts one’s offspring, via gestation and nursing, than do males.
subjective feelings of closeness and social support with However, the sex difference in overall parental invest-
him or her (Laham et al., 2005; Neyer & Lang, 2003), ment is much smaller in humans than in other mammals,
as well as one’s level of altruism toward him or her in given that both male and female humans invest heavily
imagined and real life-threatening situations (Burnstein, in caring for their children long after the infant is
Crandall, & Kitayama, 1994; Grayson, 1993; J. M. weaned. This cooperative biparental investment signifi-
McCullough & Barton, 1991). Despite the fact that cantly increases the fitness of offspring (Geary, 2000,
extended kinship systems have been reduced by mod- 2005). For instance, father presence triples the probabil-
ern mobility, children’s developmental delay in provid- ity of child survival from illness and reduces the risk of
ing sufficient energy production to sustain themselves children being murdered in hunter–gatherer, small-scale
has likely increased even more with extended adoles- societies (Hurtado & Hill, 1992; Winking, Gurven, &
cence, high economic specialization, and technological Kaplan, 2011). Paternal investment of time and financial
advances that require greater skill acquisition before resources is also related to upward social mobility of
one becomes productive. children, even when maternal characteristics are con-
Furthermore, human long-term pair bonds serve to trolled for (Kaplan, Lancaster, & Anderson, 1998). Con-
maximize parental investment. Humans are the only great versely, divorce in Western countries predicts various
apes that engage in long-term pair bonding (Dixson, negative outcomes for children, including lower educa-
2015). Despite the fact that many societies legally permit tional attainment, more aggression, more substance
men to have more than one wife, most men do not have abuse, and greater depression (Barber & Demo, 2006).
sufficient resources to attract more than a single wife, Besides the fact that men invest more in offspring
and most marriages around the world are monogamous than do typical male mammals, women are also unique
(Henrich, Boyd, & Richerson, 2012). Successful long-term among female mammals in that they often live decadesYou can also read
