Developmental Psychology

Carlson, Stephanie M.; Shoda, Yuichi; Ayduk, Ozlem; Aber, Lawrence; Schaefer, Catherine; Sethi, Anita; Wilson, Nicole; Peake, Philip K.; Mischel, Walter

doi: 10.1037/dev0000533pmid: 29939038

In the 1960s at Stanford University’s Bing Preschool, children were given the option of taking an immediate, smaller reward or receiving a delayed, larger reward by waiting until the experimenter returned. Since then, the “Marshmallow Test” has been used in numerous studies to assess delay of gratification. Yet, no prior study has compared the performance of children across the decades. Common wisdom suggests children today would wait less long, preferring immediate gratification. Study 1 confirmed this intuition in a survey of adults in the United States (N = 354; Mdn age = 34 years). To test the validity of this prediction, Study 2 analyzed the original data for average delay-of-gratification times (out of 10 min) of 840 typically developing U.S. children in three birth cohorts from similar middle-high socioeconomic backgrounds in the late 1960s, 1980s, and 2000s, matched on age (3 to 5 years) at the time of testing. In contrast to popular belief, results revealed a linear increase in delay over time (p < .0001, ηp2= .047), such that children in the 2000s waited on average 2 min longer than children in the 1960s, and 1 min longer than children in the 1980s. This pattern was robust with respect to age, sex, geography and sampling effects. We posit that increases in symbolic thought, technology, preschool education, and public attention to executive function skills have contributed to this finding, but caution that more research in diverse populations is needed to examine the generality of the findings and to identify causal factors.

Drewelies, Johanna; Agrigoroaei, Stefan; Lachman, Margie E.; Gerstorf, Denis

doi: 10.1037/dev0000527pmid: 29952599

Life Span psychological and life course sociological perspectives have long acknowledged that individual functioning is shaped by historical and sociocultural contexts. Secular increases favoring later-born cohorts are widely documented for fluid cognitive performance and well-being (among older adults). However, little is known about secular trends in other key resources of psychosocial function such as perceptions of control and whether historical changes have occurred in young, middle-aged, and older adults alike. To examine these questions, we compared data from two independent national samples of the Midlife in the United States survey obtained 18 years apart (1995/96 vs. 2013/14) and identified case-matched cohorts (per cohort, n = 2,223, aged = 23–75 years) based on age and gender. We additionally examined the role of economic resources for cohort differences in perceived mastery and constraints. Results revealed that older adults in later-born cohorts reported perceiving fewer constraints than did matched controls 18 years ago, with such positive secular trends being particularly pronounced among women. In contrast, younger adults reported perceiving more constraints in later-born cohorts than those 18 years ago and also reported perceiving lower mastery. We conclude from our national U.S. sample that secular trends generalize to central psychosocial resources across adulthood, such as perceptions of control, but are not unanimously positive. We discuss possible underlying mechanisms and practical implications.

Boutwell, Brian B.; Young, Jacob T. N.; Meldrum, Ryan C.

doi: 10.1037/dev0000537pmid: 29952603

A wealth of literature has examined the association between breastfeeding and the development of cognitive abilities in childhood. In particular, at least some evidence exists suggesting that breastfed children perform better on measures of intelligence later in life. Although a correlation appears to be present, fewer observational studies have included appropriate adjustment for potentially confounding variables; maternal intelligence, maternal education, and cognitive stimulation provided by mothers being chief among them. As a result, we analyze a national sample of approximately 790 American respondents to test the association between breastfeeding and intelligence during childhood and adolescence using multiple intelligence tests and controlling for a range of key covariates. Our results suggest that the correlation between breastfeeding throughout the first six months of life and intelligence is statistically significant and consistent, yet of substantively minor impact.

Flensborg-Madsen, Trine; Mortensen, Erik Lykke

doi: 10.1037/dev0000545pmid: 30047773

Few studies have investigated associations of milestone development in early childhood with intelligence in adulthood in typically developing children. The current study is an extension of 2 previous studies on smaller samples and investigated associations of age at attainment of 32 developmental milestones attained between 0 and 3 years of age with adult intelligence and explored whether the effects of early infant milestones are mediated through later development during subsequent years. Mothers of 8,400 children from the Copenhagen Perinatal Cohort recorded 32 developmental milestones during the child’s first 3 years of life. Information on at least 1 developmental milestone was available for 2 subsamples with adult follow-up information on intelligence: Børge Priens Prøve (BPP) was available for 2,567 men while Wechsler Adult Intelligence Scale (WAIS) was available for 1,000 men and women. The study found that early attainment of milestones, primarily those related to standing/walking and language development, was associated with higher intelligence in adulthood. The adjusted BPP means were 103.7, 101.7, and 99.5, respectively, for being able to name objects/animals in pictures at less than 18 months, 18–24 months, and later than 24 months. Mediation analyses showed direct associations of the 1-year milestones related to standing/walking with intelligence with the direct association accounting for 74.6% and 64.4% of the total association in each subsample. Thus, milestones related to standing and walking primarily show a direct association with adult intelligence and are to a smaller extent mediated by milestones reflecting development during the subsequent years, in particular language development.

Margoni, Francesco; Surian, Luca

doi: 10.1037/dev0000538pmid: 30010354

Over the past decade, numerous studies have reported that infants prefer prosocial agents (those who provide help, comfort, or fairness in distributive actions) to antisocial agents (those who harm others or distribute goods unfairly). We meta-analyzed the results of published and unpublished studies on infants aged 4–32 months and estimated that approximately two infants out of three, when given a choice between a prosocial and an antisocial agent, choose the former. This preference was not significantly affected by age or other factors, such as the type of dependent variable (selective reaching or helping) or the modality of stimulus presentation (cartoons or real events). Effect size was affected by the type of familiarization events: giving/taking actions increased its magnitude compared with helping/hindering actions. There was evidence of a publication bias, suggesting that the effect size in published studies is likely to be inflated. Also, the distribution of children who chose the prosocial agent in experiments with N = 16 suggested a file-drawer problem.

Oshri, Assaf; Duprey, Erinn B.; Kogan, Steven M.; Carlson, Matthew W.; Liu, Sihong

doi: 10.1037/dev0000528pmid: 29952602

During adolescence, a positive outlook toward the future (i.e., future orientation) can protect youth from the risks conferred by childhood adversity. Research to date, however, has largely considered future orientation as a static attribute. Developmental systems perspectives suggest that future orientation, when considered across time, will exhibit dynamic trajectories with levels changing in response to the varying balance of risks and resources in youths’ environments. Investigating the developmental course and consequences of future orientation is particularly germane to maltreated youth who may benefit from programs that target this protective mechanism. The present study tested hypotheses regarding the developmental course of future orientation, including the association of distinct future orientation trajectories with time-varying risk factors and resources, and the association of continuity and change in future orientation trajectories with young adult psychosocial functioning. Hypotheses were investigated with longitudinal (T1 Mage = 12.22, T2 Mage = 13.52, T3 Mage = 14.79, T4 Mage = 18.54), multireporter data from a nationally representative sample of maltreated youth (N = 1,461). Growth mixture modeling (GMM) identified three classes of growth trajectories in future orientation: high-persistent, low start/increasing, and high start/decreasing. Time-variant and -invariant risk factors and resources differentiated youths’ future orientation trajectories. Youth in the high-persistent and low start/increasing trajectories were more likely to attain young adulthood developmental milestones—including independent living skills, social capital, employment, and higher weekly income. This study documents how an important component of resilient adaptation emerges and promotes positive outcomes among highly vulnerable youth.

McMurray, Bob; Danelz, Ani; Rigler, Hannah; Seedorff, Michael

doi: 10.1037/dev0000542pmid: 29952600

The development of the ability to categorize speech sounds is often viewed as occurring primarily during infancy via perceptual learning mechanisms. However, a number of studies suggest that even after infancy, children’s categories become more categorical and well defined through about age 12. We investigated the cognitive changes that may be responsible for such development using a visual world paradigm experiment based on (McMurray, Tanenhaus, & Aslin, 2002). Children from 3 age groups (7–8, 12–13, and 17–18 years) heard a token from either a b/p or s/∫ continua spanning 2 words (beach/peach, ship/sip) and selected its referent from a screen containing 4 pictures of potential lexical candidates. Eye movements to each object were monitored as a measure of how strongly children were committing to each candidate as perception unfolds in real-time. Results showed an ongoing sharpening of speech categories through 18, which was particularly apparent during the early stages of real-time perception. When analysis targeted to specifically within-category sensitivity to continuous detail, children exhibited increasingly gradient categories over development, suggesting that increasing sensitivity to fine-grained detail in the signal enables these more discrete categorizations. Together these suggest that speech development is a protracted process in which children’s increasing sensitivity to within-category detail in the signal enables increasingly sharp phonetic categories.

Braham, Emily J.; Libertus, Melissa E.; McCrink, Koleen

doi: 10.1037/dev0000534pmid: 30047774

Little is known about whether and how parents can foster their children’s spontaneous focus on number, an unprompted measure of attention to small numbers of objects that predicts later math achievement. In the current study, we asked 54 preschool-aged children and their parents to play together in a children’s museum exhibit using either a numerical prompt or a nonnumerical prompt (control condition). Before and after playing with their parent, children completed assessments to measure individual differences in their tendency to spontaneously focus on number. After playing with their parent, children whose parents received the numerical prompt showed greater spontaneous focus on number compared to children whose parents received the control prompt. These findings suggest that when parents interact in an informal play setting with their children in ways that involve numerical content, it sharpens children’s later spontaneous attention to numerical information.

McGuire, Luke; Rizzo, Michael T.; Killen, Melanie; Rutland, Adam

doi: 10.1037/dev0000535pmid: 29952601

The present study investigated age-related changes in the intergroup allocation of resources depending on whether the ingroup norm was competitive or cooperative. Participants included children (Mage = 8.69), adolescents (Mage = 13.81), and adults (Mage = 20.89), (N = 263) who were inducted into simulated groups and informed about an ingroup norm of either cooperation or competition. The goal context for the resource allocation task was either prosocial (to benefit the welfare of animals in a charity event) or group focused (to win a national interschool competition). They were then asked to allocate resources between an ingroup and outgroup, and to justify their allocation. The findings showed that children allocated significantly more resources to their ingroup in order to achieve a prosocial goal, but only when the ingroup norm was competitive. In contrast, adolescents and adults allocated resources equally irrespective of the ingroup norm. These findings showed that children prioritized the moral goal of welfare over that of fairness when their ingroup favored competition, while adolescents and adults always prioritized fairness. Older participants justified their equal allocation with greater reference to the importance of fair competition. This study demonstrated an important developmental shift in how the prioritization of moral goals during intergroup resource allocation is influenced by ingroup norms of competition and cooperation.

Wölfer, Ralf; Hewstone, Miles

doi: 10.1037/dev0000547pmid: 30047775

Although literature provides strong evidence for the beneficial role of outgroup contact, longitudinal knowledge regarding the formation and change of outgroup contact remains improvable. Using a longitudinal, large-scale data set including 6,726 majority and minority participants (Mage = 14.98 years at Wave 1; 55% female) from 4 western European countries that were followed in 3 waves over 2 years, we systematically examined the development of outgroup contact during adolescence and tested the role of hypothesized predictors (i.e., intergroup attitudes and social identity) for explaining this development. In the majority, growth curve models revealed consistent patterns of ethnic homophily characterized by a continuous decline of outgroup contact, whereas this negative growth was buffered by a positive change of intergroup attitudes and a negative change of national identity during adolescence. In contrast, in the minority, outgroup contact was characterized by higher mean levels and a nonlinear development (i.e., no systematic decline or increase) of outgroup contact. Findings highlight the developmental importance of adolescence for promoting positive intergroup relations, especially for the majority, and emphasize the usefulness of contact interventions with adolescent students in school.