Tag Archives: adolescence

Crossing Disciplines and the Lifespan

Qi Wang, Chair of Department of Human Development

Reprinted from APS.org, September 28, 2018.

In a new recurring feature, the Observer showcases university labs and departments that have advanced integrative science. In the inaugural installment, APS Fellow Qi Wang talks about Cornell University’s Department of Human Development, which she chairs.   

 

What is the history of the department? What was its genesis?

The Department of Human Development at Cornell University is an interdisciplinary entity that uses multiple approaches, methods, and levels of analysis to study human development across the lifespan and integrates basic and translational research to enhance development and well-being in diverse contexts and populations. The department distinguishes itself with an ecological view of development as unfolding in multiple overlapping contexts. It has consistently been ranked as one of the top human development programs in the country.

The department, founded in 1925, was one of the first departments in the United States established by a university that focused on child development within the context of the family. Over the past 90 years, the mission of the department has expanded to include the full lifespan: Adolescence and emerging adulthood were added to early childhood development during the 1960s, and adulthood and aging were added during the 1980s. The study of contextual influences has expanded outside of the family to a greater number and variety of contexts, including peer groups, schools, neighborhoods, and workplaces. The faculty have come to include scholars of multiple disciplines and methodologies. Currently, the department has a professorial faculty of 24. Undergraduate majors typically number between 250 and 300, with approximately 35 masters and doctoral students in residence.

How has it evolved over the years?

The department has become increasingly dynamic and integrative. It has maintained its ecological focus, exemplified by the influential work of APS James McKeen Cattell Fellow Urie Bronfenbrenner, APS Past Board Member Steve Ceci, and others, and in the meantime has redefined the ecological perspective to align with the development of the general field. This is reflected in our study of an increasing number and variety of contexts and their interactions with developmental (social, cognitive, biological) processes across the lifespan. We increasingly emphasize interdisciplinary and integrative approaches that span areas of psychology (cognitive, developmental, clinical, social, cultural), along with law, neuroscience, sociology, education, and history. We recently recruited a computational political scientist who studies social networks, political communication, online social support, and health. The department also has evolved to increasingly focus on culture and diversity, examining basic developmental processes in relation to a variety of demographic factors including socioeconomic status, gender, race and ethnicity, and cultural background.

Our interest in advanced methodologies is reflected in the addition of neuroscience, biological/life sciences, and data science in the department and in the importance we place on multiple levels of analysis. From the sociology and psychology of health and aging to the neuroscience of memory, emotions, and decision-making, the department mixes equally observational and correlational studies with rigorous experimental approaches and interventions within and outside the laboratory. The department has made a strong investment in neuroscience, being the only human development program in the country to house an MRI facility. The department is also unique among human development programs in housing a nonhuman animal laboratory, allowing us to lead examinations of lifespan developmental changes in the brain and behavior and how they are shaped by diverse environmental contexts, early life experiences, and genes and their expression. The recent addition of social networks research and data science further extends our interdisciplinary strengths.

The department embraces translational activities and “use-inspired research,” seeking evidence-based solutions for real-world problems. Both its pedagogy and outreach are research-based — often research conducted by the very faculty member teaching a particular course or engaging in a particular outreach activity.

How many faculty members are in the department? What departments or disciplines are represented?

The department has consistently attracted a distinguished faculty. Many mainstream psychological scientists have decided to join our faculty, with four of our newer faculty leaving tenured positions at top psychology programs. In the past year, we have recruited four assistant professors who are among the very best of their cohort. Several members of our faculty hold National Academy memberships, including the National Academy of Education, the American Academy of Arts and Sciences, and the National Academy of Medicine. Members of our faculty have garnered just about every prestigious award within psychological science, including the APS William James Fellow Award, the APS James McKeen Cattell Fellow Award, the G. Stanley Hall Award, the Society for Research in Child Development Senior Distinguished Contributions Award, and the E. L. Thorndike Award. The department has a professorial faculty of 24, from various disciplines within psychology, sociology, political and information science, and neuroscience.

The research topics of the faculty fall into three general areas: Law and Human Development (LHD), Health and Wellbeing (HW), and Cognition in Context (CC). All areas are characterized by interdisciplinary focus, lifespan perspective, cultural diversity, multiple approaches, methods, and levels of analysis, and integrative basic and translational research to study real-world problems.

The LHD area assembles a group of world-class psychologists and legal scholars to study the interplay of law, psychology, and human development. It offers a top-notch PhD–JD dual degree program. The HW area houses leading research on typical and atypical development across the lifespan in diverse populations. Faculty in this area examine the relation between mental and physical health in response to contextual factors and have produced groundbreaking and policy-shaping work. The CC area offers the most dynamic and rigorous investigations of the developing mind in interaction with a variety of biological, social, and cultural factors. Faculty conduct research using neuroimaging, EEG, cross-species modeling, field and laboratory experiments, and longitudinal designs to understand fundamental processes underlying human mind and behavior in context.

What would you describe as the most surprising or unexpected collaborations that psychological scientists have been able to join or lead within the department?

Every generation brings new scholars from diverse disciplines to our department. Their research transforms the department into new directions and in the meantime also is transformed by the interdisciplinary culture of the department. Often they collaborate across disciplinary lines. One example is an outstanding young neuroscientist we hired, who began a collaboration with a sociologist in HD who studies aging. It is the sort of collaboration that would be unlikely in a homogenous setting. There are many similar instances of cross-disciplinary collaborations to study machine learning, affective neuroscience, decision-making, and so forth, within and outside of the department. The disciplines that have been involved in HD faculty’s collaborative research include law, particle physics, mathematics, microbiology, biomedical engineering, business, behavioral economics, communication, and information science.

Here are some of the current cross-disciplinary collaborations of our faculty:

  • A cognitive developmental scientist is working with a sociologist from Cornell’s sociology department and a particle physicist at the Fermi Lab in Batavia, Illinois, to conduct a study on women in science.
  • A cognitive developmentalist is working with a law professor at the University of Michigan on children’s testimonial competence.
  • A sociologist is working with a team of physicians and health-care providers to conduct intervention research and policy analysis related to aging and health care, using evidence-based methods to develop a competent, caring, long-term care workforce.
  • An HD neuroscientist is working with an HD sociologist on Alzheimer’s disease research.
  • An HD member has had a long-term collaboration with a professor of pediatrics at another university around the evaluation of outcomes associated with the Nurse Family Partnership program.
  • A member of HD collaborates with a member of our business school faculty on cultural influences on bias.
  • A sociologist has been collaborating with both a pediatrics professor and an epidemiologist to examine the impact of poverty-related stressors on the cognitive and physical development of children in low-income families. She also works with two members of the Communications Department at Cornell to develop social-media use for health care among older adults.
  • Another member works with a pediatrician/public health scholar in another university on the projected behavioral impacts of global climate change.
  • An HD neuroscientist collaborates with a microbiologist here on the gut–brain axis and the biome.
  • Faculty from an education department, a mathematics department, and a veterinary school have also worked with our faculty members.

Has forming an interdisciplinary entity such as this made it easier or more challenging to obtain grant funding and get research published?

Our interdisciplinary focus has made us more competitive in obtaining grant funding and getting the research published. Specifically, our research often cuts across the more traditional categories of psychology and amplifies their applied nature.

On the one hand, our faculty has demonstrated “mainstream” excellence. Our publications appear in all of the top specialty psychological journals and the top general–general journals. Our faculty also frequently publish in top specialty journals in nondevelopmental core areas of psychology. In addition to the research being of the highest quality, a key reason for our success in publishing is that our research targets theoretical and empirical questions that our peers perceive as important, no matter whether they do or don’t fit into intuitive categories.

On the other hand, our faculty also excel in many integrative and interdisciplinary publishing outlets and make broad scholarly contributions beyond their core areas and beyond psychological science. Our publications also appear in nonpsychology journals such as those focused on sociology, education, anthropology, and medicine, and as a result our work has reached vastly different audiences. In addition to peer-reviewed articles in journals outside psychology, our faculty have also published a range of influential books, op-ed pieces, and Chronicle of Higher Education articles that address a wide range of audiences. Oftentimes, building a reputation for solid work in core psychological science journals opens up opportunities for important broader contributions.

Part of the “translation” and “interdisciplinary” process is collaborating with colleagues outside the disciplines in which we were trained. There are many good examples in our department as noted earlier. Pertaining to publication, for example, several faculty have collaborated with researchers in medical fields and published in major health-related journals with high impact factors, including The Journal of the American Medical Association, Pediatrics, Annals of Internal Medicine, New England Journal of Medicine, and the American Journal of Public Health.

What are the strategies that the department has utilized in maintaining its top-rank position in the field?

One strategy is related to our hiring priorities. We hire the best people available through open searches, without constraints based on current research areas or rank. We also actively seek opportunities to hire targeted senior faculty who are superstars in the field. We are fortunate to have a very supportive dean who lets us conduct open searches and prefill lines with strong candidates and who does not rescind lines after unsuccessful searches. In addition, our faculty overwhelmingly support hiring the best people, regardless of area.

Another strategy is to self-reflect on our current research topics and to allow the department to evolve as scholarship and policy needs change. Over the years, there have been important shifts in research emphases as fields have either changed direction or ceased to exist with faculty retirement or leave.

Another effective strategy is to establish a mentoring system for junior faculty. Each nontenured junior faculty in the department is provided with a mentoring committee as soon as he/she arrives on campus. The committee consists of three tenured faculty whose research is in a similar area as that of the junior faculty. The committee provides honest and constructive written feedback to the mentee at the end of each year, which is then discussed with the mentee in person as well as reported to the general faculty. The feedback acknowledges the mentee’s achievements in research, teaching, and service and in the meantime helps the mentee identify any issues so they can be effectively addressed early on. Because of this supportive system and because we strive to hire the best people in the first place, our junior faculty have been extremely successful in their work. Many have come to be leading researchers in their respective fields. We have four APS Rising Stars, and many junior faculty have received young investigator awards from major organizations. In the past 15 years, we have not had a single case of denied tenure.

FEATURES

Qi Wang Retraces Her Path to Memory Research

Qi Wang, an Association for Psychological Science (APS) Fellow esteemed for her scientific contributions on culture and autobiographical memory, reflects on her career path in an interview with Suparna Rajaram, the President of APS.

 


Special Issue on Women in Science 

Wendy Williams, founder, and director of the Cornell Institute for Women in Science (CIWS) has edited a special edition of a journal on evidence-based research about factors that affect the academic and professional lives of women in STEM fields. In her editorial of Underrepresentation of Women in Science: International and Cross-Disciplinary Evidence and Debate, Williams provides a framework for understanding some of the issues and viewpoints that surround the debate of women in science.


Mothers Instill Eco-Awareness

Gary Evans and colleagues are the first to show that parenting can have long-term effects on pro-environmental attitudes and behaviors in adulthood. This has important implications for education and public policy.

 


Long-Term Depression Risk for Girls Who Start Puberty Early

In his blog, The Methods Man, F. Perry Wilson MD, commends the quality of Jane Mendle's research on how early puberty may lead to depression in adulthood. Her results have important implications for depression screening recommendations of girls in early puberty.

 


Too Young to Plead

In a recent paper, Valerie Reyna and Rebecca Helm reported that adolescents are more likely than adults to plea guilty to crimes they have not committed. They argue that the decision-making processes involved with plea-bargaining are developmentally immature in adolescents and they are vulnerable to pleading to a lesser charge even if innocent.

 


Mapping Emotion in the Brain

Daniel Casasanto and graduate student Geoffrey Brookshire propose an exciting new theory that, contrary to the prevailing view that different emotions are localized in specific areas of the brain, emotions are “smeared over both hemispheres” depending on an individual’s handedness.

 


The Accents We Trust

Katherine Kinzler studies the development of social cognition, with particular emphasis on exploring infants’ and children’s attention to the language and accent with which others speak as a marker of group membership. A recent article by the BBC explores her research and its implications for empathy, cultural learning, and trust.

 


 

Reprinted from Phys.org, March 15, 2018.

Teenagers are more likely to plead guilty to crimes they did not commit because they are less able to make mature decisions, new research shows.

Experts have called for major changes to the criminal justice system after finding innocent younger people are far more likely admit to offences, even when innocent, than adults.

Those who carried out the study say teenagers should not be allowed to make deals where they face a lesser charge in return for pleading guilty. The study suggests young people are more likely to be enticed by these deals, and take what they see as an advantageous offer even when they have done nothing wrong.

Most criminal convictions in the UK and the USA occur as the result of guilty pleas, rather than trial. This means the majority of convictions are the result of decisions made by people accused of crimes rather than jurors.

The research was carried out in the USA, where a system known as "plea bargaining" is utilised, but the academics say their discovery has implications for countries across the world that allow teenagers accused of crimes to receive a sentence or charge reduction by pleading guilty. Specifically, the researchers recommend restricting reductions that may entice innocent teenagers into pleading guilty and making it easier for teenagers to change pleas after they have been entered.

Other research has found adolescents are less able to perceive risk and resist the influence of peers because of developmental immaturity.

Rebecca Helm, Ph.D., HD '18

Dr Rebecca Helm, from the University of Exeter Law School, who was part of the research team said: "It is important to ensure the people accused of crimes have the capacity and freedom to make sensible decisions about whether to plead guilty. Where systems allow defendants to receive a reduced sentence or charge by pleading guilty they need to ensure that defendants are suitably developed to make such decisions and that they have the necessary levels of understanding, reasoning, and appreciation.

"We hope this research will lead to plea systems becoming fairer and less coercive for adolescents. Any restrictions on guilty pleas for adolescents would have to be introduced in a way that avoids harsher average sentences being imposed on adolescents. However, research increasingly suggests that in the same way as they are too young to vote, too young to drink alcohol, and too young to rent a home, perhaps adolescents are too young to plead guilty."

Valerie Reyna, Lois and Melvin Tukman Professor

Dr Helm and Professor Valerie F. Reyna, Allison A. Franz, and Rachel Z. Novick from Cornell University tested decision making among people of different ages. Participants were 149 adolescents recruited from high schools and middle schools in New York aged from 9 to 17, 200 students from Cornell University aged between 18 and 22, and 187 adults from across America.

Participants were given the same hypothetical situation in which they were asked to indicate the decisions they would make if accused of a crime. Participants were either asked to imagine they were guilty or not guilty of the crime, and were told the approximate likelihood of conviction at trial and the reductions that could be gained by pleading guilty as opposed to being convicted at trial.

The research found that as people become older, those who are innocent are less likely to plead guilty. Innocent teenagers indicated that they would plead guilty in roughly one-third of cases, while innocent adults indicated that they would plead guilty in just 18 per cent of cases. Importantly, when examining the decisions researchers found that teenagers were significantly less influenced in their decision-making by whether they were guilty or innocent than adults were. Results also suggest that adolescents are making decisions that do not reflect their values and preferences, including those relating to admitting guilt when innocent, due to developmental immaturity.

Although this was an experiment, the academics believe the findings have important implications for the juvenile justice system.

"Too Young to Plead? Risk, Rationality, and Plea Bargaining's Innocence Problem in Adolescents" is published in the journal Psychology, Public Policy, and Law.

Read more at: https://phys.org/news/2018-03-teenagers-guilty-crimes-didnt-commit.html#jCp

Valerie Reyna

Science Friday, August, 25, 2017.

Ira Flatow, host of NPR's Science Friday, discusses a recently published paper which HD's Valerie Reyna co-authored as part of a collaboration between researchers at Cornell University and University of Pennsylvania.

The Neuroscience of Risky Decision Making (Bronfenbrenner Series on the Ecology of Human Development)

Edited by Valerie F. Reyna and Vivian Zayas

Risky choices about sex, drugs and drinking, as well as diet, exercise, money and health care pervade our lives and can have dire consequences. Now, a new book aims to help us understand the neural roots of bad decisions. The Neuroscience of Risky Decision Making (APA Books) synthesizes the research in this relatively young field for the first time, and introduces new models of brain function to explain and predict risky behavior.

The harm caused by risky decision-making is enormous understanding how the brain processes risks and rewards is the key to unraveling the mystery of irrational decision-making in real life, said Valerie Reyna, Lois and Melvin Tukman Professor of Human Development, Director of the Human Neuroscience Institute in the College of Human Ecology and the Cornell MRI Facility.

We anticipate this work will transform the next phase of research in the field and inform policy and practice innovations that can save lives and improve health and well-being, said Reyna, who co-edited the volume with Vivian Zayas, associate professor of psychology at Cornell.

In the book, leading neuroeconomists, neuroscientists and social scientists discuss recent findings on why people take risks and how risky choices shift in different circumstances and across the life span.

Dear Readers


FEATURES

Simple questionnaire predicts unprotected sex, binge drinking

Valerie Reyna and Evan Wilhelms developed a new questionnaire for predicting who is likely to engage in risky behaviors, including, unprotected sex and binge drinking. Their questionnaire significantly outperforms 14 other gold-standard measures frequently used in economics and psychology.


  Study challenges model of Alzheimer's disease progression 

 The research of Professor Nathan Spreng and his collaborators sheds light on the basal forebrain region, where the degeneration of neural tissue caused by Alzheimer’s disease appears before cognitive and behavioral symptoms emerge.


 Social media boosts remembrance of things past

A new study – the first to look at social media’s effect on memory – suggests posting personal experiences on social media makes those events much easier to recall.


Experts Address Elder Financial Abuse as Global Problem

Financial exploitation of older people by those who should be protecting them results in devastating health, emotional and psychological consequences. International elder abuse experts met at Weill Cornell Medicine to map out a strategy for conducting research on this problem.


For kids, poverty means psychological deficits as adults

Childhood poverty can cause significant psychological deficits in adulthood, according to a sweeping new study by Professor Gary Evans. The research, conducted by tracking participants over a 15-year period, is the first to show this damage occurs over time and in a broad range of ways.


STUDENTS IN THE NEWS

Miss New York Camille Sims fights for social justice     

Camille Sims '15 says fate brought her to Cornell and the Department of Human Development. And now it has propelled her to reign as Miss New York and to finish second runner-up in September's Miss America competition.


Summer Scholar Spotlight: Brian LaGrant ‘17       

Brian LaGrant ’17, a human development major from New Hartford, N.Y., discusses his research on factors surrounding imitation among children and adults.


Risky decisions and concussions

David Garavito, graduate student in the Law, Psychology, and Human Development Program, under the supervision of Dr. Valerie Reyna, is working with communities in New York and around the country with support from an Engaged Cornell grant for student research. He is working with coaches and student athletes to study the effects of concussions on decision making about risks.


ARTICLES ON THE WEB

Alzheimer’s early tell: The language of authors who suffered from dementia has a story for the rest of us

Adrienne Day writes about how Barbara Lust, professor in Human Development, and other researchers are studying changes in language patterns in early Alzheimer’s disease.


 MULTIMEDIA

Listen to Associate Professor Corinna Loeckenhoff discuss self-continuity, or our perceived connections with our past and future selves.


Hear Professor Adam Anderson talk about his research in the podcast, "Brain waves: The science of emotion" for The Guardian.

Students and professors in Human Development worked this past summer to move their research into the real world at 4-H Camp Bristol Hills.

Kathleen McCormick '16 and Alexandra Holmes '16 invite students to join the journaling study - Mark Vorreuter

Kathleen McCormick '16 and Alexandra Holmes '16 invite students to join the journaling study - Mark Vorreuter

Guided by  human development undergraduates Alexandra Holmes '16 and Kathleen McCormick '16, campers reflected on puberty in the "Writing about Life Changes" study led by Jane Mendle, assistant professor of human development.

Following a successful pilot study last summer, Mendle is again partnering with camp director Tim Davis to study the health benefits of writing about teen transitions.

“The 4-H program has always had a wonderful connection with the university,” says Davis, interim executive director and 4-H program leader of Cornell Cooperative Extension in Ontario County.

“There is a real emphasis on how the camp experience will develop the whole child, and if there is a good fit between faculty and our priority areas – healthy living, STEM (science, technology, engineering, and math), or workforce development – we’re very open to discussing partnerships.”

Lindsay Dower ’17 guides students in a nutrition game – Mark Vorreuter

Lindsay Dower ’17 guides students in a nutrition game – Mark Vorreuter

Indeed, 4-H Camp Bristol Hills is becoming a prime spot for Cornell professors and students to pursue research and outreach projects. Along with Mendle’s study this summer, the camp hosted the “Health and Brain Neuroscience Outreach” project by Valerie Reyna, professor of human development. Lindsay Dower '17, an undergraduate in human development, engaged campers in learning about neuroscience, genetics and nutrition through interactive games and bottom-line messages about health designed to help young people make healthy choices.

Read the full story

By Karene Booker
Reprinted from Cornell Chronicle, October 9, 2014

Teaching adolescents to think more simply and categorically about risks helps them make healthier choices, finds a recently published, randomized experiment by Cornell psychologist Valerie Reyna. Her research shows that adolescents can be taught to think in these more protective, adult-like ways even though their brains are still developing, she says.

“We found that emphasizing bottom-line meaning was more effective than the standard approach for reducing risky sexual behaviors because such gist messages are preserved over longer periods and are key memories used in decision-making,” said Reyna, professor of human development in Cornell’s College of Human Ecology, reporting results from her extensive study testing interventions to reduce sexually transmitted infections (STIs) and unplanned pregnancy among adolescents.

“The goals of most risk reduction interventions are to enhance risk perceptions in order to overcome adolescents’ belief that they are invulnerable and to turn intuitive adolescent decision-makers into analytical, unbiased adults – but ironically, these aims are misguided,” Reyna said.

“Most adults reason more categorically than adolescents and base their decisions on the gist of information; they barely consider engaging in many high-risk behaviors because they intuitively grasp the risks and call up their experience and values more quickly,” she explained.

“Adolescents, on the other hand, take more time to weigh the benefits and risks, and often decide in favor of the benefits.”

Reyna and coauthor Britain Mills, Ph.D. ’09, developed a new risk-reduction program by incorporating her research on how adolescents reason into the proven sex education curriculum, Reducing the Risk (RTR). The main difference between the two curricula is that Reyna’s adaptation emphasizes framing typical sexual decisions in categorical ways that should promote risk avoidance (i.e. “even low risks add up to 100 percent if you keep on doing it”). Both curricula communicate the same facts about risk, but their gist-enhanced program, RTR+, promotes gist extraction, automatic retrieval of relevant personal values and automatic application of those values, Reyna and Mills say.

The effectiveness of the new curriculum was compared to the original and to an unrelated curriculum in a random, controlled trial design involving more than 700 youth in Arizona, Texas and New York. Participants took part in 14 hours of classroom instruction and activities, with follow-up surveys at completion and every 3 months up to a year after the intervention.

Reyna and Mills found that RTR+ produced improvements for 17 outcomes, whereas RTR produced improvement for 12. Effects of RTR+ were greater than RTR for nine outcomes and remained significantly greater than controls at one-year follow-up for 12 outcomes. Only RTR+ had a significant impact on measures of sexual behavior. Participants in the RTR+ group delayed initiation of sexual activity longer, had a lower increase in number of sexual partners, fewer unprotected sexual acts, less favorable attitudes toward sex and greater perception of risks of sex compared to the other two groups.

Their results suggest that by emphasizing gist representations, which are preserved over longer periods and are key memories used in decision-making, the enhanced intervention produced larger and more sustained effects on adolescent sexual risk taking, the authors say.

The study, “Theoretically motivated interventions for reducing sexual risk taking in adolescence: A randomized controlled experiment applying Fuzzy-Trace-Theory,” funded in part by the National Institutes of Health and the National Science Foundation, was published in the Journal of Experimental Psychology: General, 143(4).

Karene Booker is an extension support specialist in the Department of Human Development.

Related Links:

Valerie Reyna
The paper
College of Human Ecology

By Karene Booker
Reprinted from Cornell Chronicle, June 23, 2014

Mendle

Mendle

Genetic factors related to how sexually mature a girl thinks she is influence her sexual behavior, above and beyond her actual physical development, reports a new study.

The study, published in June in Developmental Psychology (Vol. 50:6), is the first to directly test the link between pubertal timing and involvement in specific sexual behaviors, disentangling the genetic and environmental influences shaping adolescent sexual timing and behavior, the authors say. Their findings indicate that unique genetic factors influencing how mature girls think they are predict their engagement in dating, romantic sex and casual sex, whereas genetic factors associated with the timing of puberty predict the age when girls first become sexually active.

Sara Moore

Moore

“We’ve known for a long time that when kids go through puberty is strongly influenced by genetic factors, but there’s more to puberty than just biology,” says Jane Mendle, assistant professor of human development in Cornell’s College of Human Ecology and recipient of this year’s Young Investigator’s Award from the Society for Research on Adolescence.

“Dramatic social and environmental changes take place as kids transition into the new roles that come with sexual maturity; it turns out that how girls interpret and respond to these changes is also genetically influenced,” Mendle says.

“While environmental influences are extremely important in the dating and sexual outcomes we studied, we were surprised that genetic factors played such a large role,” Mendle adds.

“We suspect that genetically influenced traits such as sensation seeking and sociality could be at play in shaping how teens navigate the complex social environments surrounding puberty,” says Cornell graduate student Sarah Moore, who is first author on the study, “Pubertal Timing and Adolescent Sexual Behavior in Girls” with Mendle and K. Paige Harden from the University of Texas.

The researchers analyzed information from more than 900 female sibling pairs in a national longitudinal study of adolescent health and risk behavior. The pairs included identical twins, fraternal twins, half siblings, cousins and unrelated siblings, allowing the researchers to distinguish the effects of environment from heredity.

The team found that shared genetic influences on age of puberty and on how girls perceive their physical maturity were responsible for differences in the age at which girls became sexually active. Girls who matured earlier than their peers perceived earlier maturity and also initiated sex at an earlier age. Potentially, this is because genetic factors such as hormone levels influence age of menarche and also affect visible appearance and sexual desire, the authors say.

Genetic factors related only to girls’ perceived maturity, on the other hand, were responsible for their engagement in sexual behavior. Girls who perceived earlier maturity than their peers were more engaged in dating, romantic sex and nonromantic sex. Furthermore, the team found no association between girls’ involvement in specific sexual behaviors and genetic or environmental factors influencing the onset of puberty. In other words, pubertal timing itself is not a risk factor for casual sex as some prior research had suggested, say the authors.

“Our research shows that girls’ perceptions of their pubertal development are different from their actual pubertal development and drive different outcomes down the road,” Mendle concludes.

Karene Booker is an extension support specialist in the Department of Human Development.

Related Links:
Jane Mendle
The Paper

By Susan S. Lang
Reprinted from the Cornell Chronicle, March 3, 2014

Mendle

Mendle

The age at which people become sexually active is genetically influenced – but not when they grow up in stressful, low-income household environments, reports a new study.

“Our study shows that environmental influences – rather than genetic propensities – are more important in predicting age at first sex (AFS) for adolescents from stressful backgrounds, who have few societal and economic resources,” says Jane Mendle, assistant professor of human development in the College of Human Ecology, pointing out that genes determine when teens begin puberty, which is a strong predictor of AFS.

“In fact, genes contribute only negligibly to AFS for these teens. It can almost be thought of as the environment ‘taking over’ the natural developmental trajectory that might occur in a less stressful background,” she adds.

For teens from financially advantaged backgrounds, on the other hand, the environment is much less influential and genes play a more important role in predicting AFS, Mendle notes.

The study, co-authored with University of Texas at Austin researchers, was published online in January in the journal Developmental Psychology.

While many studies have examined either genetic influences or environmental influences on AFS, “ours was one of the very first to consider gene-environment interactions in AFS, or how genetic expression may vary according to environmental circumstances,” Mendle says.

Using a sample of 1,244 pairs of identical twins (who share 100 percent of their genes) and non-twin full siblings (who share 50 percent of their genes) from the National Longitudinal Study of Adolescent Health, the researchers found that genetic influences on AFS were suppressed among low-socioeconomic-status and ethnic-minority teens compared with higher socioeconomic status and ethnic-majority youth. Father absence did not uniquely moderate genetic influences on AFS.

“And because we looked at identical twins and siblings, we could account for the importance of big family differences – and that enabled us to focus solely on understanding the environmental influences in AFS,” she says.

In addition to genetic influences, the use of twins and siblings in the study design accounted for shared environmental influences, such as religion or certain aspects of parenting, for siblings in the same family and for environmental influences that were unique to each youth.

Their findings “are broadly consistent with previous findings that genetic influences are minimized among individuals whose environments are characterized by elevated risk,” the researchers wrote.

“There has been a lot of dialogue and controversy in America on how to handle adolescent sexuality, and what programs may be most effective in reducing some of the outcomes associated with high-risk sexual behavior in teens,” Mendle says. “Many factors predict whether a teen is sexually active and when he or she transitions to sexual maturity. Our results help us understand in what contexts these factors will be malleable.”

The study, “Early Adverse Environments and Genetic Influences on Age at First Sex: Evidence for Gene x Environment Interaction,” co-authored by Texas researchers Marie D. Carlson and K. Paige Harden, received no outside funding.

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