In recent decades, ecocultural environments of the Maya in Chiapas, Mexico have undergone continuous change from more subsistence-based to more commerce-based and from more rural to more urban. Comparing ethnographic observations of one family over a ten-year period and across rural and urban environments, we used activity-setting analysis to investigate changes on the micro level that would reflect these shifts in the macro-environment. The development of commerce between 1997 and 2007 led to increased reliance on technology, increases in individuation and individual choice, specialization for economic tasks, and, for women, more formal education. Other changes in this same period of time were greatly intensified by urban dwelling: contact with strangers and people of different ethnicities, women's economic achievement, and greater freedom for young women to have unchaperoned contact with young men.

In recent decades, ecocultural environments of the Maya in Chiapas, Mexico have undergone continuous change from more subsistence-based to more commerce-based and from more rural to more urban. Comparing ethnographic observations of one family over a ten-year period and across rural and urban environments, we used activity-setting analysis to investigate changes on the micro level that would reflect these shifts in the macro-environment. The development of commerce between 1997 and 2007 led to increased reliance on technology, increases in individuation and individual choice, specialization for economic tasks, and, for women, more formal education. Other changes in this same period of time were greatly intensified by urban dwelling: contact with strangers and people of different ethnicities, women's economic achievement, and greater freedom for young women to have unchaperoned contact with young men.

Sociocultural theory emphasizes the role of culture and society on individual development (Davydov, 1995; Vygotsky, 1978). In the 21st century, media have become an essential feature of society, with the current generation of youth being the first to be defined by technology and innovation (Gardner, 2013). An examination of television, a media that can reflect cultural trends, found that the value of fame was the top portrayed value (out of a list of 16 values) in 2007, while it was near the bottom of the list in the years 1967, 1977, 1987 and 1997. During the same time period, the value of community feeling had become less visible, dropping from number one and two to number 11 in 2007 (Uhls & Greenfield, 2011). A follow up study with focus groups of fourth and sixth grade children in LA found that preteens were aware of the messages about fame in TV content, and that online media practices reinforced these messages (Uhls & Greenfield, 2012). Subsequent research using a survey with a large geographically diverse sample (N=315) found that television watching and social networking jointly predicted the value of individualism, constructed as future aspirations for fame, financial success, status and image. Collectivism did not hold a relationship with media. A last study, a field experiment with an intervention and matched control group, found that eliminating screens for five days improved preteens emotion understanding. Taken together, these studies demonstrate that 21st century media dramatically influence social and emotional development. Implications are that educators, parents and policy makers should educate youth about the impact that media has on their lives, while particular care should be taken to create opportunities for face to face social interaction as frequently as possible.

First language researchers have proposed dozens of explanations why infants across cultures seem to acquire more nouns than verbs among their earliest words. No such finding has been documented among adult foreign language learners. I wished to determine whether adults have greater difficulty learning verbs than nouns, and if so, why that could be.

To investigate whether adult college students might learn concrete nouns or verbs better, I constructed and measured a list of noun and verb concepts, images, and auditory stimuli. I measured these stimuli on many dimensions with a mind to statistically control these extraneous factors when testing for differences in noun and verb learning (Study 1). In Studies 2 and 3 I trained participants with these words and tested their recognition of targets with multiple-choice tests. I then statistically controlled and measured the effects of measured and manipulated factors to see what confluence of factors affected word learning. While there was generally a noun bias effect, I found that methods of learning and delay qualified this effect (removing the noun bias at inferential learning, and reversing the word bias at one week), image media quality is of likely help to the learner, and cross-situational learning is greatly helpful. This dissertation concludes with a summary of findings and accounts of them. Although it remained partly unclear why nouns were generally learned better than verbs, Gleitman et al.'s (2006) surface variability hypothesis was taken as the most likely account for the noun bias observed among this sample of young adults.

The present dissertation seeks to understand the origins of cultural differences in the self by examining two forms of embodied caregiving practices: eating and grooming. Although both eating and grooming lie at the intersection of culture, mind, biology, and social relationships, neither has been examined by psychologists as being possible mechanisms for cultural learning. Chapter 1 describes a mixed-methods (quantitative and qualitative) cross-cultural comparison of children's eating practices in Burma-Myanmar and the United States. The study uses naturalistic video data of 55 children during routine family mealtimes to analyze non-verbal eating behaviors. Results indicate that there are significant cultural differences between families in Burma-Myanmar and the United States in embodied eating practices with regard to three variables: 1. Independence, 2. Agency, and 3. Social Intimacy. Children in the United States are more independent in their eating than children in Burma-Myanmar. Children in the United States are also more agentic, more frequently taking the initiative to eat; in Burma-Myanmar, the caregiver more often initiates eating. Children's eating in Burma-Myanmar involves more physical intimacy than in the United States. Intimacy takes the form of sharing food, plates, or using the same utensil to feed not just the child, but another person as well. Results also indicate that cultural differences in eating practices emerge early and are sustained across a significant span of development. Chapter 2 describes a mixed-methods cross-cultural comparison of allogrooming practices in Burma-Myanmar and the United States. Using the same naturalistic video database from Study 1, Study 2 analyzes allogrooming behaviors directed at 57 children in Burma-Myanmar and the United States. Chapter 2 reports similar findings to those reported in Chapter 1 in terms of cross-cultural differences. Results indicate that there are significant cultural differences between Burma-Myanmar and the United States with regard to two variables: 1. Interdependence in Grooming, and 2. Intimacy in Grooming. Concerning interdependence, children in Burma are groomed by their caregivers more often than are children in the United States. Grooming is also more intimate in Burma-Myanmar, more often involving the inside of the child's mouth and intimate body parts or direct contact of the caregiver's hand with bodily substances of the child, such as mucous. Similar to the results reported in the first study, Chapter 2 reports that, for interdependence in grooming, cultural differences emerge early and are sustained across a significant span of development. Chapter 2 also reports that there are cultural differences in developmental trajectories for intimacy in grooming. Whereas in Burma-Myanmar, level of intimacy in grooming starts high and remains high as children get older, in the United States intimacy in grooming decreases with the child's age. A key finding reported in Chapter 1 and 2 was the variability in the Burmese sample across all variables. Chapters 1 and 2 also contain ethnographic case studies illustrating the quantitative findings with qualitative analysis. Chapter 3 contextualizes the findings from Chapters 1 and 2 and attempts to account for the variability in the Burmese sample by reporting case studies of four families in Burma- Myanmar. Using ethnographic research methods, Chapter 3 describes how recent sociodemographic changes in Yangon impact the relationship between embodied caregiving practices and abstract values. While adaptations on the part of Burmese parents to sociodemographic changes often resulted in a disjuncture and tension between embodied practice and abstract values, this observed trend was mediated by socioeconomic factors, including enrollment of children in private schools and access to higher education on the part of parents and grandparents. The present findings raise important theoretical questions about how children may learn culturally specific values about the self. Taken together, the results reported in Chapters 1 and 2 suggest that daily eating and grooming practices may be a mechanism for cultural learning, contributing to culturally divergent pathways of development of the self. The results reported in Chapters 1 and 2 also address important theoretical questions about when cultural differences in the self emerge, with both studies reporting that cultural differences in independence, agency, and intimacy are present even in the period of infancy. The observations reported in the ethnographic study raise important theoretical issues about how sociodemographic changes may alter the relationship between embodied caregiving practices and abstract parental values.

Even though more Latinas/os are enrolling in college than ever before, they continue to have significantly higher college drop-out rates compared with their other-ethnic peers. Thus, though Latinas/os want to attend college, they may have difficulty adjusting to the environment. This research examined how conflict between family obligations (e.g., spending time with family) and academic obligations (e.g., studying) – what is coined as home-school cultural value conflict – play a role in Latina/o first-generation college students’ adjustment during the transition to college. Using three different methodological techniques (group interview, survey, behavioral experiment), the research showed that Latina/o students experience these conflicts and that they play a negative role in well-being and academic achievement (i.e., attention, grades), markers important for successful college adjustment. The negative effects were greater for female students and for students living with their parents or close to home. Together, the results affirm the need to create interventions that aid Latina/o first-generation college students in harmonizing their home and school cultures.

Ethnic minorities and members of non-Western societies are considered to hold a strong sense of family obligation, which shapes behaviors and relationship characteristics. Ethnic and national group differences must be reconciled with an understanding of how economically driven transformation of learning ecologies also shape child and adolescent development worldwide. I investigated how diverse socioeconomic characteristics may shape the learning ecology that promotes cultural values (Study 1, 2, 3), daily behaviors (Study 3), and parent-child relationships (Study 3). In Study 1, I interviewed 115 children and mothers in rural Korea, urban Korea, and immigrant communities in Los Angeles, to assess familistic values. European American families from Los Angeles served as a reference group to disentangle the role of heritage culture and learning ecology. Koreans in urban Korea and European Americans in Los Angeles did not differ in familism, suggesting that urbanization may reduce East-West value differences. While the traditional value appears to lose relevance in urban Korea, Korean immigrants were more familistic than European Americans, suggesting promotion of familism in immigrant communities. Furthermore, nuclear family residence and higher education level predicted lower familism. Given that cultural learning begins early on, Study 2 tested whether parental valuation of childrearing goals is predicted by individual and national socioeconomic standing. In this study, data from 227,431 parents from 90 nations were included. Individual socioeconomic status predicted greater likelihood of personal valuation of independence and less valuation of obedience as childrearing goals; national socioeconomic characteristics predicted greater national popularity of independence and lower popularity of obedience at the nation-level. In Study 3, I tested how values shape daily behaviors and family relationship characteristics in 872 Vietnamese adolescents in rural Vietnam, urban Vietnam, and urban U.S. Family obligation values were still reinforced in urban Vietnam compared to rural Vietnam, but the values manifested in academic pursuit in urban Vietnam. Family obligation values shaped parent-child relationship characteristics in urban U.S. immigrant households. Vietnamese American adolescents with higher sense of family obligation reported less conflict with parents. This dissertation contributes to scholarship by unpacking the contributions of heritage culture and socioeconomic development worldwide.

Social media use is extremely prevalent among adolescents, leading to continued public interest in its effects on social interaction. Understanding the neural underpinnings of social media use will allow researchers to better understand these effects; but the literature on social media and the brain is, at present, remarkably limited. This dissertation examined a unique feature of digital interaction- “Quantifiable Social Endorsement” - and demonstrated that this indicator of peer opinion significantly influences both neural and behavioral responses to content posted online.

In Study 1, adolescents underwent an fMRI scan while using a tool that mimics Instagram, a popular photo-sharing social media platform. Participants viewed photos that had been ostensibly “Liked” by peers. In reality, the number of Likes was experimentally manipulated such that half of the photos appeared with many Likes (‘popular’) and half with few Likes (‘unpopular’). Included among these photos were images submitted by the participants from their own Instagram accounts and images depicting risky behaviors (e.g., drinking alcohol, smoking). Participants demonstrated significantly different behavioral and neural responses as a function of photo popularity. Participants were more likely to Like photographs if they were popular than unpopular, and popular photos elicited significantly greater activity in neural regions implicated in reward processing, social cognition, and visual attention. Behavioral effects were significantly stronger for participants’ own photographs than for photographs ostensibly supplied by peers, and participants showed significantly greater activity in the nucleus accumbens - a hub of the brain’s reward circuitry - for the popular > unpopular contrast when viewing their own photographs compared to others’ photographs.

Study 2 replicated and extended the findings of Study 1 in an expanded sample that additionally included 27 college students. Like the high-school students, college students also were significantly more likely to Like popular than unpopular photographs, and popular photographs elicited significantly greater activity in brain regions involved in social cognition, visual attention, and reward. When high-school students, but not college students, viewed risky (vs. non-risky) photographs, activation in the cognitive control network decreased. For high-school students, nucleus accumbens response to social reward (i.e., receiving many Likes on one’s own photographs) increased with age.

The findings reported in this dissertation suggest that Quantifiable Social Endorsement is a means by which peer socialization and influence occurs in online environments, including to behaviors like drinking and drug use, which represent a significant public health concern in adolescence. Furthermore, social media provide a unique opportunity to examine the neural correlates of social interaction and peer influence in an ecologically valid manner.