Abstract In this review, we evaluate developmental and personality research with the aim of determining if the personality trait of conscientiousness can be identified in children and adolescents. After concluding that conscientiousness does emerge in childhood, we discuss the developmental origins of conscientiousness with a specific focus on self-regulation, academic motivation, and internalized compliance/internalization of standards. Based on the accumulated body of evidence, we conclude that self-regulation fosters conscientiousness later in life, both directly and via academic motivation and internalized compliance with norms. We argue that elements of conscientiousness are evident by early childhood, self-regulation skills are likely a core developmental component of conscientiousness, and despite the contribution of heredity to the aforementioned aspects of functioning, environmental factors likely contribute to conscientiousness.

Integration We have argued that the development of several capacities in childhood—self-regulation, compliance/internalization with norms/standards, and academic motivation/persistence on tasks—provide the foundation for the full emergence of the personality trait of conscientious. As is indicated in , we suggest that these three abilities may differentially relate to the various facets of conscientiousness. However, we do not think that the additive effects of these three capacities tell the whole story. We view self-regulatory skills as involving basic abilities such as the capacities to inhibit behavior, manage attention, and plan. These abilities provide tools for acting in regulated ways and for behaving in a conscientious manner. However, some widely used measures of self-regulation such as delay of gratification and persistence tasks likely include motivational components as well because these tasks involve compliance with adults’ instructions or expectations and/or the desire to adhere to internalized goals. In comparison to self-regulation (especially “purer” tasks of executive functioning regulatory skills), compliance/internalization and academic motivation both include very strong elements of motivation—the motivation to conform with standards of conduct as well as the motivation to do well on tasks considered relevant to success or accomplishment in a culture. Often self-regulation may provide the tools to accomplish goals that stem from the internalization of standards or the motivation to do well. Thus, we suggest that there might be multiplicative effects when predicting conscientiousness of individual differences in childhood (and adulthood) self-regulation with individual differences in compliance/internalization of norms/standards or academic motivation (Paths 6 and 7 in ).

Conclusion and Future Directions In summary, it is clear that self-regulation, industriousness, and dutifulness/responsibility--three important facets of conscientiousness--can be seen in fairly young children. Individual differences in these constructs exhibit considerable inter-individual consistency. Developmental maturity in self-regulation likely contributes to concomitant growth in industriousness and dutifulness/responsibility. Although other factors no doubt contribute to success in achieving goals, adhering to norms and personal standards, and acting responsibly toward others, the abilities to control attention, integrate information, plan, and willfully inhibit or activate behavior play a central, enabling role. Thus, regulatory skills likely are necessary but not sufficient to the development of industrious, dutiful, and responsible behavior; for example, individual differences in regulation might relate to industriousness and dutifulness/responsibility only if children have also developed the motivation to achieve or to act in responsible/dutiful ways. Further research is necessary to document the joint role of self-regulation and factors that affect relevant motivation and internalized goals in conscientiousness across the lifespan. Many questions regarding the development and prediction of conscientiousness in adulthood remain unaddressed or unanswered. One potentially fruitful avenue for investigation is the additive or interactive effects of various aspects of childhood temperament/personality with those we targeted in this paper when predicting conscientiousness in adolescence and adulthood. For example, personality agreeableness may combine with self-regulation or internalized compliance/internalization of standards to predict conscientiousness in adulthood (Caspi & Shiner, 2006). Moreover, emotion likely plays a multi-faceted role in the motivation to behave in norm- or rule-abiding ways and to be industrious. Self-regulation and emotionality interact when predicting developmental outcomes such as externalizing and social competence (see Eisenberg, Fabes, Guthrie, & Reiser, 2000); thus, self-regulation might interact with individual differences in emotionality (both positive and negative) when predicting the emergence of conscientiousness. Emotionality might also moderate relations of conscientiousness tendencies to actual conscientious behavior or directly enhance or undermine conscientious behavior. Consistent with the latter possibility, dependability in adulthood is related not only to Big Five conscientiousness but also to Big Five emotional stability, as well as agreeableness (Roberts et al., 2005). Another issue for future work is considering how other aspects of childhood personality do or do not contribute to the development of conscientiousness. For example, it could be argued that personality agreeableness contributes to the development of conscientiousness. For example, Caspi and Shiner (2006) suggested that responsibility is based on both agreeableness and conscientiousness. If this is true, the development of prosocial values and behaviors in childhood might be relevant to the emergence of adult conscientiousness. In addition, agreeableness, which Rothbart and Bates (2006) argued might be a neglected aspect of temperament, might contribute to some degree to compliance, especially compliance that is based on the desire to please others or on adherence to internalized norms related to prosocial values. In future work, it would be desirable to determine if prosocial responding or values in childhood are predictors of adult conscientiousness and if its prediction of conscientiousness is unique from that of self-regulation and committed compliance/internalized standards. Moreover, it would be informative to determine the degree to which self-regulation and committed compliance/internalization predict conscientiousness versus agreeableness in adulthood. An issue of obvious import is the degree to which socialization experiences, exposure to demographic risk factors, and interventions—all of which appear to affect children’s self-regulation, industriousness/academic motivation, and committed compliance/internalization--have an enduring effect on conscientiousness across the life-span. It is possible that experiences later in life may dilute, nullify, or, conversely, amplify the effects of environmental influences on what we have argued are some of the origins of conscientiousness. Studies linking early socialization experiences to adults’ conscientiousness are clearly needed. Moreover, perhaps certain aspects of the familial environment (e.g., coming from an orderly environment) are important for the emergence of a stable trait of conscientiousness. Research is also needed to determine the effectiveness of interventions for changing the developmental trajectory of conscientiousness and for modifying conscientiousness after childhood. Given the strong relation of conscientiousness to a host of positive outcomes in adulthood (see Roberts et al., this issue), it is important to determine aspects of the environment that are modifiable and affect the early emergence of behaviors and motivation relevant to conscientiousness. Even if genetics plays a large role in conscientiousness and its precursors, change in socializers’ behaviors elicited by child characteristics or due to the adult’s own genetic makeup often are modifiable by the environmental interventions. In fact, there likely is a complicated interplay of genetic and environmental factors in predicting conscientiousness from childhood functioning. There is little doubt that genetics play a role in individual differences in both self-regulation and conscientiousness; some of this effect may be on variables such as executive functioning and the need for social stimulation/ interaction (e.g., extraversion) and perhaps the desire for social contact and approval. Moreover, heritable characteristics such as temperamental irritability and intelligence no doubt shape parenting behavior. However, parental values and goals, which are not entirely genetic, undoubtedly affect their socialization of behaviors such as conforming to norms, behaving in regulated and hence acceptable ways, and achieving success, and cannot be ignored. Indeed, initial research (e.g., Kochanska et al., 2011) supports the plausible assumption that genes and environmental experiences interact to affect components of conscientiousness. Several genetic polymorphisms have been associated with conscientiousness and its facets; however, the variance explained by such polymorphisms is typically extremely modest and subsequent studies often fail to replicate earlier findings (Roberts, Jackson, Duckworth, & Von Culin, 2011; South & Krueger, this issue). Genes involved in the regulation of dopamine and serotonin activity may be especially important for conscientiousness and have been related to performance on tasks assessing alerting, orienting, and executive function aspects of attention (e.g., Posner et al., 2007). Research identifying combinations of genes or their components may provide better prediction of conscientiousness. Moreover, aspects of the environment probably even activate the expression of genes relevant to conscientiousness but, to our knowledge, this issue has not been tested. Very little of the relevant research is genetically informed. To accomplish the above goals, there is a need to identify in a more systematic way empirical links between childhood temperament and adult conscientiousness. Such work seems timely given recent progress in identifying facets of conscientiousness and growing interest in how individual differences unfold across the life course. One straightforward next step would be to examine how measures assessing the constructs discussed in this article vary across the life course. For instance, by comparing items on validated questionnaires of effortful control in early childhood, self-control in middle childhood and adolescence, and conscientiousness in adulthood, one might identify specific behavioral tendencies that are consistently identified across developmental epochs (e.g., concentrating on a task and ignoring non-task distractions, planning ahead for tasks, delaying gratification) despite distinct behavioral manifestations (e.g., concentrating when drawing in a coloring book vs. paying careful attention during lectures). (See Shiner & DeYoung, in press, for an important first step in this direction.) The National Institute of Health has taken on the formidable challenge of developing computer-based performance tasks assessing functions relevant to conscientiousness (and other constructs) for individuals aged 3 to 85 years (see http://www.nihtoolbox.org). Of course, the validity of such task measures, and in particular their convergence with more ecologically valid measures of conscientiousness (e.g., informant report ratings), should be tested rather than assumed. Executive function, delay of gratification, and questionnaire measures of self-regulation tend to be only modestly interrelated (Duckworth & Kern, 2011). It is quite possible that some measures of self-regulatory capacities are more predictive of conscientiousness that others; for example, measures of regulation that include a motivational component might be more closely aligned with conscientiousness than measures that are more purely attentional and/or cognitive. Moreover, multi-task batteries of self-regulation (or compliance, internalization, or academic motivation) measures would probably increase reliability and validity of relevant measures and provide better prediction of the various facets of conscientiousness across time. Further, in an effort to understand how the dutifulness component manifests in both childhood and adulthood, it is important to develop ways of measuring internalized compliance in adults. One method may be to consider measures of guilt after transgressions, which is likely related to internalization and the facet of responsibility. Similar measures with children have been used to assess children’s moral selves (Kochanska et al., 2010). In addition, aspects of adults’ adherence to normative standards may be available in existing scales, such as Gough’s (1994) socialization scale, a subscale of the California Personality Inventory thought to tap individuals’ internalization and compliance with positive values and norm-observing behavior (i.e., compliance with standards). In fact, this scale had been positively associated with ratings of adults’ conscientiousness (Gough, 1994). Thus, Gough’s scale and other existing adult personality measures with relevant items (e.g., items on Block’s, 1961, Q-sort; see Gough, 1994) could be examined in relation to childhood measures of internalized compliance and norm-abiding behavior, perhaps even in existing longitudinal data sets (especially those in the Bay Area where Gough and Block worked). Creative efforts to construct indices of conscientiousness and its likely childhood precursors from measures in existing studies would leverage those data while efforts are collect longitudinal data on the origins of conscientiousness are underway.

Acknowledgments Writing of this article and some of the research discussed were partially supported by a grant from the National Institute of Mental Health to the first and third authors and by a grant from the National Institute of Child Health and Development to the first, third, and fourth authors. Valiente and Duckworth were also supported by the National Science Foundation and National Institute of Aging, respectively. We thank Kelly Allred for her assistance with this manuscript.