When does Liking Children Lead to Parenthood? Younger Siblings, Implicit Prosocial Power Motivation,...

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Journal of Cultural and Evolutionary Psychology, 4(2006)2, 95–123 DOI: 10.1556/JCEP.4.2006.2.2

WHEN DOES LIKING CHILDREN LEAD TO PARENTHOOD?

YOUNGER SIBLINGS, IMPLICIT PROSOCIAL POWER MOTIVATION, AND EXPLICIT LOVE FOR

CHILDREN PREDICT PARENTHOOD ACROSS CULTURES∗

ATHANASIOS CHASIOTIS1,*, JAN HOFER1, DOMINGO CAMPOS2

1 University of Osnabrück, Germany 2 University of Costa Rica, Costa Rica

Abstract. This study tests the cross-cultural applicability of a developmental pathway model explaining childbearing as behavioral outcome variable. This is done by using the childhood context variables birth order and implicit prosocial power motivation, and explicit love for children in adulthood as predictors. The model assumes that the interactional context of having younger siblings during childhood shapes the development of implicit prosocial motivation which in turn influences the verbalized, explicit articulation of parenting attitudes finally leading to becoming a parent. After examining the data for comparability across three selected cultures from Latin-America, Africa, and Europe, the model was tested via structural equation modelling. Results showed that the model is valid for males as well as females and can be applied in all three cultural samples. These findings point at a universal developmental pathway by specifying contextual and motivational factors leading to parenting behavior. Implications for evolutionary, cross-cultural, and developmental psychology are discussed. Keywords: birth order, childbearing motivation, cross-cultural developmental psychology, evolutionary psychology, explicit self-report measures, implicit motivation, life-history theory, parenthood, parenting motivation, structural equation modelling Parenthood is a significant component of human behavior. It constitutes an investment in genetic offspring as a part of parental reproductive strategies while at the same time transmitting cultural values and practices between generations. In the literature, explicit parental socialization goals and ethnotheories are regarded as

∗ Correspondence concerning this article should be addressed to Athanasios Chasiotis,

Cross-cultural Life-span Psychology Research Group, University of Osnabrück, Department of Human Sciences, Seminarstr. 20, D-49069 Osnabrück, Germany. Phone: (+49) 541-969-4208. Fax: (+49) 541-969-4770. E-mail: Athanasios.Chasiotis@uos.de

A. CHASIOTIS, J. HOFER, D. CAMPOS

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influential variables in creating and transmitting culture-specific developmental pathways (GREENFIELD, KELLER et al. 2003; KELLER and GREENFIELD 2000). However, the emphasis on the culture-specificity of these developmental pathways (CHASIOTIS, BENDER et al. in press; KELLER, LOHAUS et al. 2004; KELLER, YOVSI et al. 2004) precludes neither implicit mechanisms (e.g. MAYNARD and GREENFIELD 2003) nor universal psychological mechanisms that can lead to these developmental differences.

Although much contextual and cultural variation in parenting behavior has been reported (BORNSTEIN 1994; GREENFIELD and SUZUKI 1998), in this study we focus on the psychological roots of this culturally divergent parenting behavior in asking which explicit and implicit motivational mechanisms lead to becoming a parent. Viewing development as the interface between biology and culture to integrate biological opportunities and constraints with cultural norms and values over the lifespan (KELLER and GREENFIELD 2000; KELLER 2002), it is assumed that a universal developmental pathway might be responsible for the emergence of parenting behavior. Furthermore, explicit psychological measures are not sufficient to explain parenting or reproductive behavior in general since many of its features are not necessarily represented on a conscious level and are thus not accessible through self-inspection or self-reports (DALY and WILSON 1999).

STUDIES ON PARENTING MOTIVATION1 In order to conceptualize the motive to become a parent, social and behavioral scientists commonly use broad motivational terms like fertility desires or expecta-tions which are generally based on the concept of desired family size (MILLER 1995). In psychology, this motivation has often been considered an interaction of a belief or cognitive component with a motivational value. Thus, a more or less rational decision-making model as in the theory of reasoned action is assumed (cf. AJZEN and FISHBEIN 1980; MILLER 1995). A shortcoming of these approaches is the lacking attention to biological underpinnings of childbearing and parenting motivation in spite of abundant evidence for neuroendicrinological regulatory mechanisms for the reproductive behavior in mammals (PRYCE 1992; ROHDE 2006). Ethologists (LORENZ 1943; see also BOWLBY 1958, 1969) were the first to describe the “releasing” effect of certain morphological features of newborn mammals (“Kindchenschema”) on adult animals causing them to show a set of parental caretaking affects and behavior. While there are approaches considering sociocognitive and motivational aspects of becoming a parent which go beyond these rather narrow boundaries of social, psychological, or biological science (e.g. MILLER 1995; MILLER and PASTA 2002), we would like to dissociate the more implicit motivational underpinnings shaped by individual experiences during early, preverbal childhood from the verbalized, explicit representations emerging and

CHILDHOOD CONTEXT, PARENTING MOTIVATION, AND BEHAVIOR

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establishing themselves during adolescence and early adulthood. This is achieved by taking an evolutionary life history perspective on parenting motivation.

LIFE HISTORY PERSPECTIVE According to the evolutionary life history perspective, human reproductive investment across the lifespan can be divided into two categories: somatic effort, and reproductive effort. Somatic effort entails childhood and growth, while reproductive effort can be further subdivided in mating, parenting, and extraparental (nepotistic) effort (ALEXANDER 1987). To each of these developmental phases a corresponding motivational state can be assigned: in childhood, the dominant motivational state is the security or attachment system (BOWLBY 1969), in adolescence and early adulthood the autonomy and mating system (BISCHOF 1975) and finally, after reaching adulthood, the caregiving motivational system (PRYCE 1992). This consecutive sequence is not without overlaps since the hierarchical taxonomy of motives allows for having different motives at the same time (HUXLEY 1942; MAYR 2001). This means that there are permanent motivational trade-offs which can also be observed in human opportunity conflicts between current (and future) activities. From the perspective of life history theory, the motivational situation of deciding whether or when to bear a child, i.e. the problem of the optimal timing of becoming a parent, is a proximal realization of the evolutionary trade-off problem between current and future reproduction (also known as the General Life History Problem, cf. CHISHOLM 1999; STEARNS 1992).

Although it is argued that during most of our evolutionary history becoming a parent was not dependent on a desire to have children, but on a desire to have sex (DIAMOND 1997; MILLER 1992), the experience of caring for younger siblings could have been a driving force behind the development of a desire to have own children. Discussions on the evolutionary functionality of parenting motivation often stress the life phase specificity of the corresponding motivational systems. But what is yet not realized is that the uniqueness of the rewarding feelings of nurturance, generally described as expressions of the activated parental motive-tional system during the transition to parenthood from pregnancy to postpartum (e.g. FLEMING, STEINER et al. 1997; FLEMING, RUBLE et al. 1997; STOREY, WALSH et al. 2000) could depend on caregiving experiences as an older sibling during childhood. Thus, the desire to have own children might be evolutionarily new, since it requires representation of the future and the consequences of sex, but responsiveness to children (through the “Kindchenschema”, cf. LORENZ 1943) is a part of our evolved mammalian heritage. Even more, as we argue here, the motivation to care for genetically related, but not own children (like nices, nephews, or younger siblings) as a part of nepotistic altruism ultimately increasing our indirect fitness (HAMILTON 1964) is independent of the desire to have sex or own children. And since humans are exceptional mammals in that males are also

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providing parental care, male parenting motivation can also be expected although differing in quantity and quality and for quite different reasons (paternal care as mating effort, e.g. HAWKES 1991; see also BJORKLUND and PELLEGRINI 2002). Thus we assume that this caring motivation emerges in both sexes during child-hood, is implicitly represented, and leads to an explicit liking of children in adult-hood and ultimately to childbearing.

INTERACTIONS WITH YOUNGER SIBLINGS One of the main characteristics of childhood context is birth order or – more specifically – the interactional experiences with siblings. Without taking sides in the controversy concerning the peculiarity of a specific birth position and its influence on personality and social development (BJORKLUND and PELLEGRINI 2002; HARRIS 1998; SULLOWAY 1996), the position we base our model on is uncontroversial, namely that caretaking behaviors of older siblings can be evoked by the presence of younger siblings (cf. HARRIS 2005). Taking a cross-cultural perspective, EDWARDS (1992, 1993) reported that nurturance together with dominance are the two behaviors consistently found around the world in older children’s interactions with younger ones. According to EDWARDS (1992), gender-independent nurturant beha-vior can be observed as long as the younger child is a toddler. Studies have also shown that children as young as age four perform motherese in the presence of younger children (PAPOUŠEK and PAPOUŠEK 1987; SHATZ and GELMAN 1973) and show behavioral patterns of cultural teaching (MAYNARD 2002) or of the culture-independent intuitive parenting program (PAPOUŠEK and PAPOUŠEK 1987; see also KELLER, CHASIOTIS and RUNDE 1992; KELLER, LOHAUS et al. 1999). Additionally, the existence of younger siblings seems to delay reproductive development at least in females (CHASIOTIS 1999; CHASIOTIS, KELLER and SCHEFFER 2003; HOIER 2003; JONES, LEETON et al. 1972), which can be interpreted as an adaptive delaying of own direct reproductive efforts to act as a surrogate parent or “helper at the nest” for younger siblings (BELSKY 1997). Finally, whether one has siblings has also been argued to influence the development of an implicit prosocial power motive as it is an important responsibility training (WHITING and WHITING 1975; WINTER and BARENBAUM 1985).

IMPLICIT PARENTING MOTIVATION MCCLELLAND, KOESTNER and WEINBERGER (1989; see also DECHARMS, MORRISON et al. 1955) distinguished between two motivational systems: on the one hand, there is a motivational system operating on the conscious level (explicit or self-attributed), on the other hand, another motivational system works on the preconscious level (implicit). The latter sytem represents highly generalized affec-

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tive preferences for certain states or behaviors. These preferences explain long-term spontaneous behavioral trends (MCCLELLAND 1987). It is assumed that implicit motives are built on early prelinguistic affective experiences and remain affectively aroused by them rather than by salient social experiences (MCCLELLAND, KOESTNER and WEINBERGER 1989). This seems to be the reason for their substantial predictive validity concerning long-term behavior compared to self-reports of explicit goals and values (MCCLELLAND and PILON 1983; see also HOFER and CHASIOTIS 2003; HOFER, CHASIOTIS and CAMPOS 2006). Particularly interesting in this respect are studies with evidence that implicit motives are also strongly related to endocrinological processes (MAZUR and BOOTH 1998; MCCLELLAND 1987; SCHULTHEISS, DARGEL and ROHDE 2003a) while explicit self-reports are not (ARCHER 1991; MCCLELLAND, KOESTNER and WEINBERGER 1989). Accordingly, studies have supported the notion that implicit motivation plays an important role in generative goals in general (MCADAMS 1985; see also HOFER, BUSCH et al. 2005) and reproductive behavior like age at first sexual experience (MCCLELLAND 1987; WINTER 1973; WINTER and STEWART 1977), sexual activity (SCHULTHEISS, DARGEL and ROHDE 2003b), or number of children (PETERSON and STEWART 1993) in particular.

Since implicit motivation does not have any symbolic representation but is reflected in people’s imagination, it is assessed using projective or operant tests such as the Thematic Apperception Test (TAT; MURRAY 1938; for cross-cultural applications see HOFER, BUSCH et al. 2005; HOFER and CHASIOTIS 2003, 2004; HOFER, CHASIOTIS et al. 2005). According to KUHL (2000, 2001), implicit motives are associated with implicit representations of the intuitive-holistic semantic network of extension memory, while explicit representations of motives are associated with the sequential-analytical operations like planning and thinking of intention memory (cf. BEEMAN, FRIEDMAN et al. 1994). Therefore, implicit motive tests are qualified for assessing contents of preverbal developmental phases and manifestations of unconscious affective dispositions.

The three basic implicit motives are affiliation, achievement, and power (cf. MURRAY 1943; MCCLELLAND 1987). The present study focuses on the power motive which is defined as one’s desire to have impact on the emotions or behavior of other people (WINTER 1991). It is assumed that a particular type of realization of the power motive is associated with childbearing or parenting motivation (see Method section). There is considerable amount of evidence that people realize their implicit need for impact by either a prosocial (socialized power; e.g. parenting) or an antisocial direction (personalized power; dual nature of power, cf. MCCLELLAND 1975; WINTER 1973). Thus, the motivational source for caretaking behavior may not be represented by the strength of the power motive but rather by an individual’s prosocial realization of the need of power (see also HOFER et al. 2005; CHASIOTIS, BENDER et al. in press).

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AIM OF THE STUDY All studies on childbearing and parenting motivation either investigated mainly ex-plicit or implicit motivation on childbearing and were either developmentally or, more rarely, cross-culturally oriented. Furthermore, a satisfying combination of im-plicit and explicit measures on childbearing motivation in one study is still missing (MILLER and PASTA 2000, 2002; MILLER, PASTA et al. 2000). This study aims at combining these research orientations by considering explicit and implicit

Figure 1. Path model on developmental mechanisms of parenthood

motivation on parenthood with a cross-cultural developmental perspective. We assume that the childhood context is important for the emergence of prosocial power motivation by being exposed to interactive experiences with younger, genetically related children which elicit certain stimuli facilitating prosocial, nurturant motivation and caretaking behaviors. This implicit parenting motivation in turn, lead to a higher amount of positive, loving feelings towards children on the conscious level, which ultimately affect reproductive behavior by becoming a parent. The basic assumption is that this postulated developmental pathway holds true between the sexes and across cultures (see Figure 1).

METHOD Sample

Selection of cultures. To test universal assumptions, it is necessary to select a variety of samples which represent a high degree of cultural diversity. Such a range of variety is covered by our cultural samples recruited from Africa (Cameroon), Europe (Germany), and Latin-America (Costa Rica). The selected cultures not only differ regarding socio-economical conditions (e.g. Human Development Index, see UNDP 2004), but also with respect to socio-cultural orientations, norms, and values (e.g. individualism and power distance, HOFSTEDE 2001).2 Assuming that sociocultural orientations draw on construals of the self, the selection of our cultural samples was also based upon KAĞITÇIBAŞI’s (1996, 2005) considerations to diffe-rentiate the dimensions of interpersonal distance (separateness – relatedness) and agency (autonomy – heteronomy). The combinations of these dimensions relevant

younger siblings parenthood love for

children

implicitparenting

motivation

Childhood context

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to our study are independence, interdependence, and autonomous relatedness. Independence is defined as comprising autonomy and separateness, an adaptive pattern in Western, industrialized societies. Therefore, we selected a German sample described as expressing prototypical independence (cf. KELLER, YOVSI et al. 2004). The prototypical interdependent sociocultural orientation – defined as comprising heteronomy and relatedness – is adaptive in populations with a generally lower socioeconomic and educational status. For the purpose of this study, we selected a sample from the Cameroonian Nso, one of the largest ethnic groups in the Western grass fields located in the North-West province of Cameroon (anglophone part of Cameroon; see NSAMENANG and LAMB 1994, 1995; YOVSI 2003). Finally, the autonomous related orientation is adaptive in traditionally interdependent cultures characterized by increasing urbanization, education, and affluence (KAĞITÇIBAŞI 2005): Since Costa Ricans have been described as valuing relatedness in family relationships, stressing closeness, respect, and harmony, while at the same time the enhanced standard of education supports autonomy (cf. KELLER, YOVSI et al. 2004), we selected a Costa Rican sample from the capital San José. Results from own recent cross-cultural research on different psychological domains (guiding principles in life: HOFER, CHASIOTIS and CAMPOS 2006; generativity: HOFER, BUSCH et al. 2005; theory of mind and inhibitory control: CHASIOTIS, KIESSLING et al. 2006; implicit motive orientation and autobiographical memory: CHASIOTIS, BENDER et al. in press) match well with these arguments.

Participants. In total, data were collected from 529 participants (see Table 1). One hundred and eighty two of these were from Germany, 176 from Costa Rica, and 171 from Cameroon. The entire sample included 273 female and 256 male participants. In total, age of participants ranged from 22 to 65 years (M = 35.33; SD = 9.30). While women and men did not differ in mean age, Cameroonian parti-cipants (M = 31.32; SD = 7.80) were significantly younger than Costa Rican (M = 36.92, SD = 9.80) and German participants (M = 37.50, SD = 9.20; F(2,527) = 25.76; p < .001). Referring to participants’ level of education, 37.2% of the total sample (n = 196) had an education below secondary school and 62.8% (n = 331) of the study participants had either secondary school or university education. Cultural samples were balanced concerning participants’ gender and level of education. Four-hundred and one participants had a steady partner (married: n = 216) and 128 participants stated that they were currently not engaged in a steady partnership (divorced or widowed: n = 55). Two-hundred and forty-seven (46.3%) of the study participants were childless and 282 (53.7%) had at least one child (range: 1 to 9; see Table 1). While two thirds (62.6%) of the German participants had no children, only one third (31.8%) in the Costa Rican and less than half (45%) of the Cameroonian sample were childless.

Coding of birth rank was based on the four categories suggested by WAGNER, SCHUBERT and SCHUBERT (1979; see also LAMB and SUTTON-SMITH 1982): only child, firstborn, middleborn, and lastborn. Since the first six years are considered the psychologically most important for individual development (JAFFE 1991; LAMB

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and SUTTON-SMITH 1982), coding was done by considering an interbirth interval of six years in each sample. This functional and not biological definition of birth rank (cf. SULLOWAY 1996) led to a redefinition of the biological birth ranking in approximately 10% of the subjects (see also CHASIOTIS, KELLER and SCHEFFER 2003). For the purpose of this study, birth rank was dichotomized in “without younger siblings” (only children and lastborns) and “with younger siblings” (first- and middleborns). As Table 1 shows, our cultural samples differed significantly in having younger siblings. While almost half of the German (45.1%) and Costa Rican (44.30%) participants did not have any younger siblings, only 21.1% of the Cameroonian participants did not have younger siblings.

PSYCHOLOGICAL MEASUREMENTS Test methods were administered individually by native research assistants of the respective country. First, data on implicit motivation were assessed. Next, information on explicit motives was obtained. All data on implicit motivation were coded by well-trained and experienced German raters after a bilingual research assistant (native Latin-American) had translated responses given by Costa Rican participants from Spanish into German. Interview language in Germany was German and in Cameroon English (official language).

Implicit parental motivation. To assess implicit power motivation, the Operant Multi-Motive-Test (OMT; KUHL and SCHEFFER 2001), developed in the context of the theory of personality systems interactions (PSI theory; KUHL 2000, 2001) was administered. Using this technique, which represents a modification of the original TAT, a set of ambiguous picture cues (sketches and/or blurred photographs) is presented to participants who are asked to imagine a story on each of the picture cues. In the simplified version of the OMT used in the study at hand, participants did not have to write down a complete story but to answer three questions: What is important for the person in this situation and what is he/she doing? How does the person feel? Why does the person feel this way?3

Like with the TAT, participants’ responses are coded for presence of the three basic social motives of achievement, affiliation-intimacy, and power (cf. WINTER 1991). Unlike with the TAT, however, in addition to the identification of a motive (only one motive per picture is coded), the predominant mode of motive realization, i.e. the underlying cognitive system and mechanisms of affect regulation guiding motive realization is specified. In this way, the OMT differentiates four approach components and one avoidance component for each motive on the basis of crossing two affective sources of motivation (positive vs. negative) with self-determined vs. incentive-focused forms of motivation. The realization of each motive can either be positively or negatively affectively toned and either be grounded in the self or in external incentives (KUHL 2001; see also DECI and RYAN 1985). The differentiation of five forms of motivation allows for testing theoretically interesting differences in

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the type of self-regulation involved in need-satisfaction (cf. BAUMANN, KASCHEL and KUHL, in press).

For the power motive this gives the following combinations: The combination of a negatively toned power motive and self-activation represents the motive realization of self-assertion against resistance, while if self-activation is lacking there is an inhibited mode of realization or, if a negative affect is mentioned in combination with a lack of self-activation, a realization of the passive avoidance component of the power motive is coded (e.g. feelings of powerlessness). A positively toned power motive based on external incentives is equivalent with an implicit striving for status, while a positively toned power motivation stemming from the self is the implicit desire to guide others in a prosocial manner. This last configuration is of particular interest as this mode of motive realization is linked with unselfish help and support given to others (cf. a prototypical OMT-response coded for prosocial power: What is important for the person in this situation and what is he/she doing? – Instructing and leading the young. – How does the person feel? – Feels patient. – Why does the person feel this way? – As an elder or leader he needs to guide the young). As such, it is hypothesized that this motive configuration best reflects an implicit parenting motivation.4

Extensive research on convergent validity of the OMT with the TAT is reported in KUHL (2001) and SCHEFFER (2005). The OMT’s validity was also shown by studies identifying behavioral correlates (BAUMANN, KASCHEL and KUHL, in press; SCHEFFER 2005; see also SCHEFFER, KUHL and EICHSTAEDT 2003). Its cross-cultural applicability has been tested along with a TAT – picture set (CHASIOTIS and HOFER 2003; HOFER and CHASIOTIS 2005; HOFER, CHASIOTIS et al. 2005). The twelve pictures used in the present study have proved to be applicable for the measurement of implicit motivation and its specific modes of realization in Germany, Costa Rica, and Cameroon.

Participants’ answers to the picture cards were scored for power motivation by five experienced coders who achieved percentage agreements of 85% or better in their responses to training material prescored by experts in OMT – workshops based on the manual by KUHL and SCHEFFER (2001). Initially, the responses of 100 participants were scored by all raters to examine agreement of codings for power. As reliability of rater was found to be sufficiently high (e.g. category agreement for prosocial power > .85), the remaining data sets were scored separately. However, coding difficulties were resolved by discussion in regular meetings. For the purpose of the present study, the sum of the prosocial component of the power motive was computed to assess the strength of the implicit motivation.

Explicit parental motivation. Explicit parenting motivation was assessed with the Fondness of Children Scale (FCS; ROHDE 2006). This scale consists of seven items that have to be rated on a 5-point Likert scale (1–5) with higher scores indicating higher fondness of children in general (e.g. “People around me would say that I am very fond of children”, “I find small children bothering”). Three negative

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poled items are recoded before a sumscore is determined indicating the general preference for children. Table 1. Sample characteristics and descriptive statistics of implicit prosocial power and love for

children (N = 529)

All Germany(GER)

Costa Rica(CR)

Cameroon(CAM)

Sample differences

N 529 182 176 171 Gender (% female) 51.5 49.5 54.5 50.9 χ ²(2,527) = .61

Age in years range mean (SD)

22–65 35.33 (9.3)

24–57 37.50 (9.20)

22–56 36.92 (9.80)

25–65 31.32 (7.80)a

F(2,527) = 25.76***

Younger siblings (%) yes no

62.9 37.1

54.9 45.1

55.7 44.3

78.9 21.1

χ ² (2,527) = 27.75*** Educational level (%) below high school at least high school

37.2 62.8

34.3 65.7

37.7 62.3

39.8 60.2

χ ²(2,527) = 1.17 (n.s.) Number of children range no children (%) at least one child

0–9 46.7 53.3

0–6 62.6 37.4

0–8 31.8 68.2

0–9 45.0 55.0

χ ²(2,527) = 34.42*** Prosocial power motivation range mean (SD)

0.50 (0.74)

0.27 (0.52)b

0.62 (0.83)

0.62 (0.79)

F(2,527) = 13.57*** Love for children range mean

4–21 14.42 (3.60)

4–21 14.27 (3.93)

4–0 15.02 (3.84)

4–20 13.97 (2.83)

F(2,527) = 2.48 (n.s.)

* p < .05; ** p < .01; *** p < .001 Scheffé–Tests: aCAM < GER and CR; bGER < CR and CAM.

RESULTS In the following we first review the equivalence of measurements across cultural groups. We present analyses on bias of picture cards used for the assessment of implicit power motivation and on cross-cultural applicability of the questionnaire on fondness for children (FCS). Next, we will briefly present findings on cross-cultural differences and in how far individual (age, gender) and sociodemographic characteristics (level of education) relate to our psychological measurements. Finally, the proposed intrapersonal psychological mechanisms concerning parenting motivation across gender and cultural groups are examined using multigroup structural equation modeling.

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METHODOLOGICAL ISSUES: EQUIVALENCE OF MEASUREMENTS ACROSS CULTURES

Implicit parenting motivation. A 12-picture set was used in the present study which proved to represent a valid tool for the assessment of implicit needs in the three cultural groups. The OMT was used in recent extended methodological studies which aimed to develop bias-free picture sets for implicit motive measurement in Germany, Costa Rica, and Cameroon (cf. CHASIOTIS and HOFER 2003; HOFER and CHASIOTIS 2005). The methodological approach which realized an integrated examination of construct, method, and item/picture bias (VAN DE VIJVER and POORTINGA 1997) is described BY HOFER, CHASIOTIS et al. (2005) considering the TAT as example. Referring to the OMT, the 12 cards were selected from a pool of 32 cards which were initially tested for applicability across cultural groups. However, it was decided to scrutinize data for picture bias again because data on applicability of the OMT stimulus material in non-Western cultures is still scarce.

Loglinear model analysis was used as technique to identify bias. This method has proved to yield good results in detection of biased dichotomous items, allows analyzing data from more than two groups at the same time, and enables identifying uniform and nonuniform bias (e.g. KOK, MELLENBERGH and VAN DER FLIER 1985; WELKENHUYSEN-GYBELS and BILLIET 2002). Loglinear modeling tests for a given picture card the fit of nested models to the observed frequencies in the cross-tabulation of categoric variables. Among hierarchically related models the most parsimonious model that fits the data is preferable. A saturated model that would perfectly match the observed frequencies includes all possible one-way and two-way effects, that is score level, culture, and interaction of culture and score level. Therefore, a more parsimonious model that fits the data must be identified.

An item shows no nonuniform bias when a model including score level and culture does fit the data. Furthermore, a fitting model that includes only score level indicates the absence of uniform bias, i.e. participants with the same overall score on average have the same score with respect to a given picture/item irrespective of the culture they pertain to (KOK et al. 1985). Likelihood ratio chi-square was used as test statistic for model evaluation. As recommended (e.g. LORD 1980), an iterative strategy was used in bias analyses: after the identification of the most significantly biased item new score levels and score groups were determined. The procedure was repeated until the set was free of items that are significantly different.

In this study, participants’ power motive scores were used as dependent variable (0 = no coding / 1 = coding). “Culture” and “score level” represented the factors. A preliminary screening of cards’ stimulus pull for power showed that one picture should be removed because of its low cue strength for the implicit need for power, i.e. less than five percent of participants’ answers showed power motive (n = 22). The cue strength of the remaining eleven picture cards for power ranged from 16.8 to 80.5%. Power codings of all five motive components were summed

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across eleven picture cards (possible range: 0 to 11) to obtain an estimator of the latent trait. Subsequently, two evenly sized score level groups (low and high strength of power motive) were differentiated.

Whereas in the first run of analyses none of the cards was identified for nonuniform bias, three cards showed uniform bias. In the next step, the picture set was reduced by the most biased item (χ ² = 15.24; p < .01). Ability indices and score level groups were recalculated and analyses were rerun. In subsequent analyses, none of the remaining ten picture stimuli proved to be biased (uniform and non-uniform). Thus, for subsequent analyses participants’ scores for implicit prosocial power were summed up across ten picture cards. Since this set of ten pictures shows no bias across cultures, our measure of implicit parenting motivation is equally applicable in all three cultural samples (for descriptive statistics see Table 1).

Explicit parenting motivation. By confirmatory factor analysis (CFA; AMOS 5; ARBUCKLE 2003), data on love for children were scrutinized for measurement invariance across cultural groups. Such a procedure is indispensable to guarantee that the latent variables in the structural model on parenting motivation are psychometrically sound (BYRNE 2001). We specified a model for each cultural group and tested for equivalence of factor loadings (measurement weights) across cultural groups by considering a one-factor model. In the first run of CFA, it was indicated that three of the items should be dropped from further analyses because their factor loadings were non-significant within the Cameroonian subsample (critical ratios < 1.20).

Multigroup analyses were successfully rerun with the remaining four items. Nested model comparisons by the use of chi-square difference test showed that the implementation of model constraints (equality of measurement weights) did not lead to a significant increment of the χ ² statistic (unconstrained model – measu-rement weight model: Δχ² = 10.16; df = 6; p = .19). Thus, the more parsimonious model was superior to the unconstrained model. The factor loadings of the remaining four items range from .71 to .39 for Cameroon, from .73 to .55 for Costa Rica, and from .70 to .61 for Germany. From the perspective of multiple fit indices (see BOLLEN and LONG 1993), it was indicated that the specified measurement weight model adequately fit our data (see Table 3): the ratio χ²/degrees of freedom lay below the critical value of 2. The Goodness of Fit Index (GFI) was above .90 and the Root Mean Square Error of Approximation (RMSEA) fell below .05. Also, the Akaike Information Criterion (AIC) and Expected Cross Validation Index (ECVI) of the default model lay below their corresponding parameters for the saturated model. The satisfying Cronbach’s Alphas of the cross-culturally applicable Fondness for Children Scale (FCS, 4-item scale) were .66 (Cameroon), .73 (Costa Rica), and .78 (Germany).

Zero-order correlations of implicit and explicit measures of parental motiva-tion with number of children. As Table 2 shows, explicit and implicit parenting motivation was correlated in the Cameroonian and Costa Rican sample, but not in

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the German sample. Concerning number of children, while implicit prosocial motivation correlated only weakly in the Costa Rica sample, in all samples there were correlations between explicit love for children and number of children.

Table 2. Zero-order correlations between implicit prosocial motivation (OMT), explicit parenting motivation (FCS), and number of children in Germany (GER), Costa Rica (CR), and

Cameroon (CAM)

Love for children (FCS)

Number of children(age controlled)

OMT GER CR CAM

–.03 .15* .18*

.03 .14 –.02

FCS GER CR CAM

.13 .22** .16*

* p < .05; ** p < .01.

EFFECTS OF CULTURE, AGE, GENDER, AND EDUCATION5 Investigating the effects of culture, age, gender, and education on our dependent variables, a MANCOVA with culture as independent variable was conducted. Age, gender, and education served as covariates and implicit prosocial motivation, explicit love for children, and number of children were the dependent variables. All multivariate tests were significant, so that tests of effects between groups could be carried out. Concerning culture, while explicit love for children showed no significant differences, implicit prosocial motivation (Scheffé-Test, F(2,527) = 13.57; p < .001; partial η2 = .050; see Table 1) and number of children (Scheffé-Test, F(2,527) = 20.72; p < .001; partial η2 = .073) were significantly lower in the German sample compared to the Costa Rican and Cameroonian sample. While male and female participants did not differ in implicit prosocial motivation, female participants (M = 14.95; SD = 3.54) score higher on the love for children scale than male participants (M = 13.84; SD = 3.57; F(1,527) = 13.76; p < .001; partial η2 = .026). Moreover, there were significant effects of education: while there were no differences in implicit prosocial motivation, higher educated participants showed less love for children (M = 14.14; SD = 3.68) and had fewer children (M = 1.04, SD = 1.40) than less educated participants (FCS: M = 14.90; SD = 3.41; F(1,527) = 6.36; p < .01; partial η2 = .012; number of children: M = 1.76; SD = 1.82; F(1,527) = 19.09; p < .001; partial η2 = .035). Finally, since number of children correlated highly significant with age (r = .54; p < .001), the unstandardized residual of number of children regressed on age was used in further analyses to correct for the influence of age on number of children.

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EXPLAINING CULTURAL DIFFERENCES IN IMPLICIT PROSOCIAL MOTIVATION

Explicit parenting motivation, assumed to represent more the salient state of parenting motivation in our model, was not related to the childhood context variable of having younger siblings and showed no significant cultural differences. Implicit prosocial motivation, on the other hand, which is regarded as rooted in childhood interactional experiences, was significantly higher in participants who experienced interactions with younger siblings in childhood (M = .59; SD = .79) than parti-cipants without younger siblings (M = .34; SD = .62; F(1,527) = 15.22; p < .001; partial η2 = .028) and was significantly lower in the German compared to the Costa Rican and Cameroonian sample. Since implicit prosocial motivation was associated with the existence of younger siblings and showed cultural variation, while the existence of younger siblings also differs across cultures, a further exploration of their relationship was warranted.

To investigate the impact of this childhood context variable on cultural differences (aiming to “unpeel the onion called culture”, cf. POORTINGA, VAN DE VIJVER et al. 1987; see also VAN HEMERT 2003), implicit prosocial power motiva-tion was first regressed on the variable “younger siblings”. In the next step, the unstandardized residual of implicit prosocial motivation of that regression analysis was reentered in an ANOVA with culture as predictor. The ANOVA with the residual of implicit prosocial motivation as dependent variable and culture as predictor showed a remarkable decrease in effect size (F(2, 527) = 11.28; p < .001; partial η2 = .041): The decrease of the effect size of culture from .050 to .041 means that 18% of the impact of culture on implicit prosocial motivation was caused by the existence of younger siblings. Thus, a remarkable amount of about one fifth of the effect size of “culture” on implicit parenting motivation can be traced back to birth rank effects.6

EQUIVALENCE OF PSYCHOLOGICAL MECHANISMS Finally, we tested whether our assumed model that the presence of younger siblings in childhood leads to a more pronounced implicit prosocial power motivation which represents a source for a higher explicit motivation for parenting (FCS) which in turn leads to becoming a parent holds true across cultural groups (see Figure 1). As we were also interested in whether our assumptions hold true regardless of participants’ gender, we specified six groups (cultures by gender) for multigroup structural equation modelling. Having verified equivalence of psychological measurements across groups in earlier analyses, i.e. by bias analyses with respect to implicit prosocial power motivation and by CFA with respect to data on FCS, we conducted multigroup path analyses with manifest variables and constrained structural paths to be equal across the six groups.

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The results indicate that a model with constraints on structural paths did not show an impairment of fit in comparison to the model with no equality constraints imposed (Δχ² = 10.25; Δdf = 15; p = .80). Based on multiple fit indices for the model, we can conclude that the causal structure related to the model of parenting motivation is equivalent across cultural groups (e.g. GFI = .98; RMSEA = .00; see Table 3).

Table 3. Fit indices of measurement model for FCS (measurement weight model) and of structural

path model on parenting motivation (structural weights model)

Model χ² (p-level) df χ² / df GFI RMSEA AIC

(saturated)ECVI

(saturated) Measurement Model

13.57 (.33)

12 1.3 .99 .01 49.57 (60.00)

.09 (.10)

Path Model

18.89 (.97)

33 .57 .98 .00 72.89 (120.00)

.14 (.23)

In the model, all structural parameter estimates were statistically significant

(critical ratio > 1.96) with critical ratios (CR) ranging from 2.69 to 3.91. In detail, there was a significant relationship between the presence of younger siblings and implicit power motivation (CR = 3.91; p < .01; βs range from .132 to .197; see Table 4). Furthermore, implicit power motivation was a significant predictor of consciously represented fondness of children (explicit motivation) (CR = 2.69; p < .01; βs range from .083 to .154) which in turn predicted parenthood (CR = 2.79; p < .01; βs range from .087 to .163; see Table 4). Thus, the psychological mechanisms leading to parenthood are the same in male and female participants regardless of their cultural background.7

Table 4. Standardized regression weights of the multi-group comparison with six groups

Standardized regression weights

Multi-group comparison (6 groups) YS – IPM IPM – FCS FCS – P Cameroonian males (N = 84) .145 .154 .087 German males (N = 92) .197 .083 .163 Costa Rican males (N = 80) .164 .111 .123 Cameroonian females (N = 87) .132 .132 .075 German females (N = 90) .195 .093 .131 Costa Rican females (N = 96) .164 .116 .122

Note: YS = Younger Siblings; IPM = Implicit Parenting Motivation; FCS = Fondness of Children Scale; P = Parenthood

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DISCUSSION This study is innovative with regard to its applied measures and its content: we selected cultural samples from Latin-America, Africa, and Europe differing with respect to their sociocultural orientations to investigate a universal developmental pathway leading to parenting behavior by using birth rank as a childhood context variable, and implicit and explicit measures of parenting motivation. As we could verify that measurements of variables used in this structural path model were psychometrically sound, it can be suggested that findings on the relations among constructs in the hypothesized theoretical model are valid (see BYRNE 2001). Therefore, it can be concluded that the psychological mechanisms of parenting behavior are the same in male and female participants and in all cultures under examination in this study. In the following, before discussing methodological implications and limitations, we will outline implications of our results for evolu-tionary, cross-cultural, and developmental psychology.

Implications for evolutionary approaches in psychology. There is a longs-tanding controversy over what constitutes an appropriate evolutionary analysis of behavior (cf. ALEXANDER 1990; CRAWFORD 2000; COSMIDES and TOOBY 1987; SYMONS 1987; TURKE 1990). One party emphasizes indicators of reproductive success like number of (surviving) children and regards ecological factors as determinants. Since it is assumed that the individual acts to maximize reproductive success, this approach is referred to as “Fitness Maximization” or Darwinian Anthropology (TOOBY and COSMIDES 1992). Evidence of a connection between contextual (e.g. father absence: HOIER 2003; QUINLAN 2003) and sociodemog-raphic factors (e.g. mortality rates: cf. BERECZKEI and CZANAKY 2001; HILL, ROSS and LOW 1997; WILSON and DALY 1997) on the one hand and marker of reproductive development like onset of puberty or age at first sexual activity on the other prove the fruitfulness of this life history perspective in psychology. At the same time, these studies demonstrate a lack of knowledge about the psychological mechanisms involved to link context with behavior.

The other approach is called “adaptation execution” or Evolutionary Psycho-logy (TOOBY and COSMIDES 1992) and argues that humans are characterized as being equipped with “old genes in a new environment”. This means that selective forces in the past (the “environment of evolutionary adaptedness”) shaped human reproductive behavior. Therefore, psychological adaptations which determine human behavior are related to their assumed natural history and are considered as (non- or) maladaptive in modern environments. In evolutionary psychology, the psychological “missing link” between evolution and behavior is mainly sought on an information-processing or computational level (COSMIDES 1989; COSMIDES and TOOBY 1987, 1996; GIGERENZER 1996) where cognition and motivation cannot be distinguished (TOOBY, COSMIDES and BARRETT 2005). Investigations on adaptive cognitive representations in evolutionary psychology are partly based on computer simulated data (to identify “simple heuristics”, GIGERENZER, TODD and the ABC

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RESEARCH GROUP 1999) or on data obtained in experimental contexts (COSMIDES and TOOBY 1992; GIGERENZER and HUG 1992), but the bulk of the data are self-reports with questionable ecological validity (DALY and WILSON 1999).

Taking a motivation psychology perspective, human behavior is determined by two distinct motivational systems, one on the conscious (explicit or self-report) and one on the preconscious (implicit) level (for modern cognitive theories which also support the notion of two motivational systems see BUCCI 1985; EPSTEIN 1994; REBER 1993; see also CHASIOTIS and SCHEFFER 2001; HASHER and ZACKS 1984; HILL and HURTADO 1996). Accordingly, the debate between the “fitness maximizing” – camp of Darwinian Anthropology and the “adaptation executioner” – camp of Evolutionary Psychology within the evolutionarily oriented scientists can be enlightened by the idea that this methodological difficulty could be one major hindrance to the convergence of thoughts between the two orientations. Perhaps “counting babies” is really not enough (CRAWFORD 2000), but relying solely on self-reports is most probably not enough either. It is also not very fruitful to take reproductive markers like age at menarche or age at first pregnancy as proxies for implicit childbearing motivation (MILLER and PASTA 2000, 2002) since they are indicators of the developmental and behavioral outcome of implicit motivation, not implicit motivation itself. If Darwinian Anthropology is more interested in what people “really do” rather than what they “merely say” (CRONK 1995), and Evolutionary Psychologists claim that “what people say is an important part of what they do” (DALY and WILSON 1999, p. 514), a combination of explicit self-reports (to know what people say what they do) and implicit data (to know what they really would like to do) will work better. For example, in our case, relying solely on explicit data on love for children, we would not have discovered the path leading from childhood context (younger siblings) to childbearing. And since it is already known that number of siblings and number of own children often are correlated (in this sample: r = .29, p < .001), our model highlights one possible psychological mechanism involved in this correlational, but psychologically agnostic pattern, namely the implicit parenting motivation emerging non-deliberately by the interactional experiences with younger siblings in childhood. Therefore, the proposed solution would be neither to count babies nor to study proximate mechanisms, but to trace explicit and implicit psychological mechanisms involved as well as to identify adaptive relations between environment and human behavior across diverging cultures.

Implications for parenting studies and demography. Many studies on paren-ting do not address parenting motivation per se presumably because it is a very natural, self-evident thing to become a parent. At least from a European perspective, this seems to be no longer true. The study’s main research question, how and why individuals might differ in motivation to become a parent, is a growing issue in many modern industrialized countries facing decreasing fertility rates and increasing numbers of childless couples. In Germany e.g. the current total fertility rate is below replacement level with 1.36 children per ever married woman

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compared to a total fertility of four to eight children in traditional, pre-industrialized societies (CAMPBELL and WOOD 1998).

Why is fertility particularly low in the most affluent and highly educated (KOHLER and RODGERS 2003)? ROHDE (2006) discusses this aberration of the fertility pattern in industrialized societies as maladaptive and offers the invention of effective oral contraceptives as explanation. But his argument does not only fall short of explaining anything on psychological grounds, it is not sound, e.g., regarding the US, where the fertility pattern is quite different, although the scien-tific level in contraceptive technology is comparable to Europe (KOHLER, BILLARI and ORTEGA 2003). The psychologically interesting question therefore is: why are some people motivated to bear children and do not use (or “forget” to use) contraceptives and others not?

In demography, reasons for not having children often are discussed in a rational framework considering cost-benefit calculations like opportunity costs of childbearing and the necessary measures which should be taken to make child-bearing more probable (e.g. KOHLER, BILLARI and ORTEGA 2003). From a motivational perspective (KUHL 2001), this approach is concentrated on downregu-lating negative affect since becoming a parent appears to be more a burden than an asset. But parenting also involves a positive affect which is a crucial element in prosocial caregiving and parenting motivation, an aspect not very much pronounced in the debates on (lowest-low) fertility: having children and caring for children is (also) fun. In our view, to understand where the fun of having children comes from and under which circumstances it is reduced is a worthwhile enterprise (see also the social intuitionist stance on moral emotions for taking a similar perspective, HAIDT 2001; LIEBERMAN, TOOBY and COSMIDES 2004; VOLAND 2004).

Furthermore, there are empirical hints in historical (VOLAND, DUNBAR et al. 1997) and contemporary demography (BIRG 1996) as well as in cross-cultural (RAEFF, GREENFIELD and QUIROZ 2000) and evolutionary developmental psycho-logy (CHASIOTIS, SCHEFFER et al. 1998) for an inertia of one generation in human reproductive behavior. Our model offers a possible explanation for this inertia: if own reproductive behavior depends on the family constellation during childhood, social change is explicitly articulated a generation after its behavioral implemen-tation. As an example, this can be observed in contraceptive use of “the pill” in the Sixties in Germany. Contrary to common interpretation, the behavioral “decision” for fewer children did not emerge after the invention of the pill but in the generation of these women’s mothers. So, according to BIRG (1996), it is more accurate to say that modern use of contraceptives is not the cause, but the effect of a behavioral decision already made a generation before. Applying our results to this issue, one could speculate about a positive feedback between decreasing numbers of siblings leading to ever more decreasing numbers of children. But, as recursive dynamics of demographic development imply, there are demographic factors like favourable conditions of reduced cohort sizes (KOHLER, BILLARI and ORTEGA 2003) or

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colonizing ecological contexts (CAMPBELL and WOOD 1998) which probably will counteract this downward spiral of fertility decline.

Concerning the adaptivitiy of this inertia, intergenerational context continuity might play a role (CHASIOTIS 1999; CHASIOTIS, SCHEFFER et al. 1998; CHASIOTIS, KELLER and SCHEFFER 2003; CHISHOLM 1999). If the socioecological context remains the same or at least similar from childhood to early adulthood, a certain correlation between number of siblings and number of own offspring would be adaptive. If the social or ecological context changes (or if the number of siblings was not the optimally realized number), a weaker or no correlation would be expected. Moreover, it should be kept in mind that many other socioecological cues like childhood mortality rates (CHISHOLM 1999) and contextual variables like kinship networks (TURKE 1989) and direct childcare (BERECZKEI 1998) might influence childbearing motivation as well.

Implications for cross-cultural psychology. In cross-cultural studies on the “value of children” it is repeatedly shown that the psychological value of children depends on sociocultural factors like, e.g. the availability of resources so that one could get the impression that loving children is conditional (TROMMSDORFF and NAUCK 2005). But these cross-cultural differences need not to be taken as ontological differences of parenting motivation per se (cf. BROWN 1991). Instead, we assume that at the core of the variance in measures like economic, social, or psychological value of children lies the desire to have children and this in an important part is due to a constellation of the childhood context variables birth order, implicit prosocial motivation, and the liking of children which ultimately lead to childbearing.

The identification of meaningful context variables helps to disentangle the often fuzzy conception of culture that dominates many cross-cultural comparisons (POORTINGA, VAN DE VIJVER et al. 1987; VAN HEMERT 2003). Our data support the view that context variables like birth order might exert similar influences on psychological, somatic, and reproductive trajectories across different cultures. Furthermore, since we could show that a remarkable amount, i.e. about one fifth of the effect size of culture on implicit motivation can be traced back to birth rank differences between the cultural samples, it could be speculated that the psycholo-gical characteristics that are attributed to different cultural differences reflect systematic differences in family constellations in different societies. For example, the differences in self-orientations which are interpreted as culture specific independent or interdependent selves (MARKUS and KITAYAMA 1991; KAĞITÇIBAŞI 1996, 2005) might at least partly depend on systematic biases of individuals with or without siblings in the cultural samples (CHASIOTIS, KELLER and SCHEFFER 2003; see also footnote 6).

Methodological considerations. Before investigating our developmental path model across cultures, we first had to test the cross-cultural applicability of the measures. This was particularly relevant because the Operant Multi-Motive Test as well as the Fondness of Children Scale have scarcely been employed in non-

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Western cultures so far. Concerning the OMT, after the removal of only two out of twelve picture cues a bias-free stimulus set was available. Thus, as a metho-dological result, a new measure for the assessment of implicit prosocial power motive (OMT; KUHL and SCHEFFER 2001) has been shown to be applicable cross-culturally. Consequently, we have a broad basis of data on implicit motivation upon which to ground our statements concerning the model’s component of unconscious parenting motivation. After three items were excluded from the scale, the Fondness for Children Scale (FCS; ROHDE 2006) was also reliably applicable across cultures. The items which had to be removed were the three negatively poled statements and showed non-significant factor loadings only within the Cameroonian subsample. Apparently, especially the Cameroonian participants had difficulties in answering the negatively articulated items on fondness for children. Since the FCS is higher in female participants and correlates with number of children, these expected effects can also be interpreted as a construct validation of this scale (cf. MILLER 1995).

Limitations and outlook. The results presented in this paper have to be interpreted with caution as this is the first attempt to systematically apply a developmental path model concerning parenting motivation in non-Western cultural samples. One important substantial objection on motivational grounds is that, besides interactions of independent implicit motives (cf. HOFER, BUSCH et al. 2005), interactions of implicit and explicit measures can also exert an influence on psychological and behavioral outcomes (e.g. motive congruence between explicit goals and implicit motives, cf. BAUMANN, KASCHEL and KUHL, in press; HOFER and CHASIOTIS 2003; HOFER, CHASIOTIS and CAMPOS 2006). Therefore, it would be interesting to investigate the impact of (in-)congruence between implicit and explicit love for children on childbearing behavior. For example, in contrast to Costa Rican and Cameroonian participants, implicit prosocial motivation in German participants seems to have a somewhat detached relation to explicit love for children and to number of children (see Table 2). Additionally, one should keep in mind that implicit prosocial power motivation is not the only possible motivational force leading to childbearing. Besides other (culture-specific) implicit power motive realizations, implicit affiliation motives can also be related to parenting motivation and perhaps vary between cultures.8

Interesting in this regard is also the notion that it does not have to be the interactions with younger siblings which facilitate the development of implicit prosocial motivation in childhood. According to Sarah Blaffer HRDY’s cooperative breeding hypothesis (2005; see also VOLAND, CHASIOTIS and SCHIEFENHÖVEL 2005) and to findings on cultural teaching (MAYNARD 2002; see also MWERU 2005), more remotely genetically related children like nieces, nephews, younger cousins (or even unrelated peers, cf. HARRIS 2005) could also elicit implicit parenting motivation. Related to that reasoning, our instrument for explicit love for children measures love for children in general, and not explicit love for own children. On the other hand, a self-report measure on love for own children probably might prove to be not very valid due to ceiling effects and response biases

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like social desirability (CRONK 1995). Anyway, further studies with more sophis-ticated psychological measures are needed to clarify how important interactions with (un-)related younger children in childhood are for implicit prosocial motivation and what influence they generally exert on later parenting behavior.

What should also be kept in mind is that our results do not mean that age at first birth is earlier in individuals with younger siblings since we controlled for age. We did not investigate (the delay in) age at first birth because in lowest-low fertility countries like Germany this is often due to socioeconomic factors like youth unemployment and opportunities for higher education, while social norms concerning childbearing age are more important in more traditional cultures like Cameroon (KOHLER, BILLARI and ORTEGA 2003; CAMPBELL and WOOD, 1998), factors which are not relevant to the purpose of our study. Additionally, taking into account that almost half of our participants did not have any children (see Table 1), only a more categorical, qualitative statement on childbearing motivation can be made. What our results mean is that irrespective of age, it is more probable that people with younger siblings have at least one child than people without younger siblings.

The findings reported here prove a cross-cultural life-history perspective on parenting motivation to be very fruitful as the developmental path model leading to childbearing holds for males and females as well as across diverse cultural settings. Nevertheless, a (preferably longitudinal) replication of the present research and an expansion on other (e.g. Asian) cultures is highly desirable.

ACKNOWLEDGEMENTS

This study was supported by two grants of the German Research Foundation (Deutsche Forschungsgemeinschaft) to the first two authors (CH242/3–1 and CH242/3–3). We would like to thank Heidi Keller, Julius Kuhl, Percy Rohde, David Scheffer, and Eckart Voland for valuable comments on an earlier draft of this paper and Relindis Yovsi, Carolina Cardenas, Holger Busch, Birk Hagemeyer, and all our research assistants in Germany, Cameroon, and Costa Rica for their help in data acquisition.

1 The terms parenting motivation and childbearing motivation will be used interchangeably. 2 The Human Development Index (HDI) is calculated on the basis of data on life

expectancy, education, and Gross Domestic Product per person (GDP). Values of the HDI (see UNDP 2004) indicate that the three nations differ from each other in three essential elements of human life: longevity, education, and living standards. Whereas Germany (HDI rank 14) and Costa Rica (HDI rank 45) are both listed among the countries with high human development, Cameroon (HDI rank 134) is characterized as showing low human development. Concerning the broad psychological dimension of Individualism-Collectivism, HOFSTEDE (2001) reported higher individualism score (from 1 to 100) for Germany (67) compared to Costa Rica (15). Cameroon

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was not included but a sample of West African regions, which may represent a rough approximation for Cameroon, yielded an individualism score of 20.

3 In the full version of the OMT, a fourth question (How does the story end?) is additionally asked.

4 In the literature on childbearing motivation, parenting motivation might be assigned to the affiliation motive (see e.g. nurturant bonding, cf. MILLER, PASTA et al. 2000) but in our view caregiving and nurturant behavior is a prosocial realization of the power motive to have impact on the emotions and behaviour of other people, while the affiliation motive represents a desire for establishing, maintaining or restoring close relationships (cf. WINTER 1991; KUHL and SCHEFFER 2001). Nevertheless, parenting motivation most probably is a combination of prosocial power and affiliation motivation (see also CHASIOTIS, BENDER et al., in press and footnote 8).

5 Partial eta-squared (η2) was used as an index of the strength of association between an independent variable and a dependent variable; partial η2s of .01, .06, and .14 can be interpreted as small, medium, and large effect size, respectively (COHEN 1988).

6 The psychologically rather crude measure of “number of siblings” reduces the effect size even more (F(2,527) = 5.16, p < .01, partial η2 = .019), i.e. from a medium (.050) to a small (.019) effect size. Thus, up to 62% of the original effect size of culture on implicit prosocial power motivation can be traced back to sibling effects.

7 Additionally, we tested the fit of the assumed model on the basis of three groups (culture) and two groups (gender), respectively. Results indicated that the data fit the model with similarly adequate fit indices than the solution for six groups. Even more interesting, a model without implicit prosocial power motivation indicated no direct path between the presence of younger siblings and explicit love for children. PERCY ROHDE (personal communication, November 10th, 2005) also did not find any correlations between FCS with birth order variables. Further statistical information (e.g. covariance matrices of the measurement model and the tested path models) can be requested from the authors.

8 For example, there is a significant correlation (r = .24; p < .05) between number of children and an implicit striving for status only in the female Cameroonian sample pointing at a more culture-specific relation of achieving higher social status as a woman by becoming a mother and having (many) children in Cameroon. On the other hand, implicit affiliative motive realizations are mainly related to number of children in the German female sample.

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