Demography of Aging Center
The Center for Health and Wellbeing is home to a Demography of Aging Center, funded by the National Institute of Aging. The center has funded 30 pilot projects to date. Active projects include the following:
Adult Age Differences in Decision Making and Reward-Based Learning
PIs: Ben Eppinger, Leigh Nystrom, and Jonathan Cohen, Princeton University
Older adults tend to be more risk avoidant and conservative in their decision making than younger adults. Moreover, it has been shown that the quality of decision-making and problem solving as well as risk adjustment is reduced in older age. These age-related impairments in decision-making have a high relevance for daily life because they affect older adults’ economic decisions, as well as decisions on medical treatments. Findings from recent studies point to the view that age differences in decision-making result from underlying deficits in the function of the midbrain dopamine system, which has also been shown to play an important role in reward processing and reward-based learning. However, so far only a few behavioral studies on age differences in decision-making have been performed and we lack a clear understanding of how aging affects the neural systems involved in decision-making and how these changes are related to age differences in reward processing and reward-based learning.
The aims of this fMRI pilot project were twofold. First, age differences in the neural systems involved in intertemporal choice is investigated, using a standard delay-discounting task (McClure et al., 2004). The behavioral results confirmed age-related reductions in delay discounting. Furthermore, less impulsive decision-making in older adults was associated with lower ventral striatal activations to immediate reward. Older adults (mean age = 70) showed an overall higher percentage of delayed choices plus reduced activity in the dorsal striatum than younger adults (mean age = 21), pointing to a reduced reward sensitivity of the dorsal striatum in older adults. Taken together, these findings indicated that less impulsive decision-making in older adults is due to a reduced sensitivity of striatal areas to reward, perhaps due from well-known transformations in dopaminergic neuromodulation with age.
Second, the effects of aging on the neural correlates of reward-based learning in a reinforcement-learning paradigm is examined looking at whether older adults differ from younger adults in their sensitivity to aversive, as opposed to rewarding, outcomes. Participants were asked to either learn to choose actions that lead to monetary reward or learn to avoid actions that lead to monetary losses. Behavioral results showed age-related impairments in learning from reward but not in learning from monetary losses. Consistent with these results, we observed age-related reductions in brain activity during learning from reward in the ventromedial PFC. Furthermore, analysis revealed a reduced responsivity of the ventral striatum to reward prediction errors during learning in older than younger adults. This age-related reduction in striatal sensitivity to reward prediction errors may result from a decline in phasic dopaminergic learning signals in the elderly.
An Exploratory Study of the Occurrence of Pharmaceutical-Induced Aging Symptoms in the United States and in Brazil
PI: João Biehl, Princeton University
This study is a preliminary assessment of how medical professionals and patients identify and treat pharmaceutically-induced aging symptoms in Brazil. Brazil has one of the highest frequencies of drug-induced adverse symptoms in the world. This study is divided in two parts: 1) Identify and interview five to ten health professionals who are currently working in Gerontology and Neurology and/or medical scientists who are carrying out studies on the field of pharmaceutically-induced aging conditions in the city of Porto Alegre, the capital of the southern state of Rio Grande do Sul. The interviews will inquire about the prevalence and clinical forms of pharmaceutically-induced aging symptoms in their routine practices and what challenges these conditions pose for diagnosis and treatment. 2) With the assistance of the health professionals, identify and interview ten adult patients who would be willing to participate in the study. The interviews will inquire about their life history and medical trajectories, aiming to assess the impact that these conditions have on their functionality and quality of life.
Another Hispanic Paradox? SES Gradients in Health among Hispanics
PIs: Noreen Goldman and Cassio Turra (PhD candidate), Princeton University
Estimates of SES gradients in health and health-related behaviors by race and ethnicity in the U.S. reveal that differentials by education across numerous measures of health status and health behaviors are virtually absent for the Latino population. Specifically, among adults interviewed in the Los Angeles Families and Neighborhoods Survey (L.A.FANS) there is no apparent gradient by years of education for obesity, depression, smoking status, and binge drinking. In contrast, findings for non-Hispanic whites are consistent with expectation: persons with more education have significantly better outcomes on each of these measures as compared with their less educated counterparts. Similar results pertain to adolescents interviewed in L.A. FANS: the frequency of obesity, smoking and binge drinking is significantly related to education for non-Hispanic whites but not for Latinos.
These findings may be related to a different pattern commonly referred to as the Hispanic paradox: i.e., although their social and economic status falls considerably below that of non-Hispanic whites, the health and survival status of Hispanics as a group is comparable to, or better than, that of non-Hispanic whites and better than that of other minority groups. Despite the large literature on the Hispanic paradox and the even more extensive one pertaining to social inequalities in health, the absence of these SES gradients among Latinos has received very little notice from epidemiologists and social scientists.
Assays of Immune and Inflammatory Markers in SEBAS
PI: Noreen Goldman, Princeton University
This pilot project is an expansion of existing work being conducted by Dr. Goldman. For the past 15 years, Dr. Goldman and her colleague Dr. Maxine Weinstein (Georgetown University) have been directing a national survey operation in Taiwan under the auspices of the Bureau of Health Promotion in Taiwan, with funding from NIA.
The objective of this survey, known as the Social Environment and Biomarkers of Aging Study (SEBAS), has been to explore linkages between the social environment and physical and mental health. SEBAS is based on a random subsample of the Taiwan Longitudinal Survey of Aging (TLSA), a national survey that includes adults approximately age 50 and older. Together with TLSA, the SEBAS data comprise extensive household interviews every three or four years (beginning in 1989 and going through 2011), two rounds of biomarker and genetic measures and information from clinical exams (2000 and 2006), and links with death certificates.
Communicating cancer risks to general, older, and underprivileged populations
PI: Talya Miron-Shatz, Postdoctoral Research Associate, Princeton University
This study focused on the way people understand communications regarding two prevalent kinds of cancer. Specifically, the focus was on prostate cancer, and on breast cancer associated with mutations of the BRCA 1 and BRCA 2 genes.
Multiple health communications convey to the public the risks associated with these types of cancer, mostly as a means of getting people to undergo testing. However, Risk information is most typically presented in probabilistic terms, possibly undermining people’s ability to comprehend it (Grimes & Snively, 1999; Statham & Green, 1993). The main difficulty people have with this presentation format is that the reference classes are not specified. This study examined the extent to which people comprehend the reference classes pertaining to the types of cancer (for example, do the percentages of penetrance refer to the general population or to women with these mutations, such that have or have not been diagnosed?).
Two additional factors that may hamper understanding and affect risk perception are that the population for whom this information is relevant is often well above middle-age (this is particularly true of prostate cancer). Studies show a mental decline that is positively correlated with age, even in educated individuals. Furthermore, and regardless of age, a fair portion of the population is bound to be less educated and with less access to resources. Few studies have examined the comprehension of underprivileged populations (but see Hutchinson, Gilvarry, & Fahy, 2000 for a rare peek into lower cognitive skills of this group).
The Determinants of the Distributions of Heights within and Across Populations
PI: Angus Deaton, Princeton University
This pilot project examined the determinants of the statistical distributions of population heights within and across countries around the world, providing greater insight into the contributions of early life nutrition and disease burden to the distribution of population health.
This project focused on two key issues.
The first concerned the measurement of the distributions of heights using data from a large number of countries to construct the distributions of heights (means, variances, etc.) by birth cohort. The huge advantage of this methodology was that time series data can be generated from a single cross section, and panel data from a set of cross-sections. These panel data were matched on date of birth and country to national income accounts, food availability data, education levels, and so on. However, the construction of height distributions is complicated by several factors, including shrinkage with age, and misreporting of height in surveys in which it is self-reported. Therefore, how best to correct for these sources of bias was explored.
The second issue was whether information on the evolution of the distributions of heights within countries over time, and comparisons of the distributions of heights across countries, can provide information on the distributions of factors such as nutrition and the disease environment that influence height. There is a large literature on the relationship between inequality in health and income inequality. The study of height, as a measure of health in early childhood, can potentially contribute to this literature. Deaton examined whether, because height in an increasing function of income, increasing income inequality showed up in increased inequality of heights. Similarly, he examined whether inequality in resource allocation across groups (such as social class or gender groups) showed up as inequality in heights across such groups.
The Efficacy of Smartphone Technology for Collecting Data on Disadvantaged Men with Chronic Health Problems
PI: Sara McLanahan, Princeton University; Co-Investigator: Naomi Sugie, PhD Candidate, Princeton University
The objective for this pilot project was to study how smartphones can improve researchers’ ability to collect data on prematurely aging, disadvantaged men with chronic health problems. The research has two aims: first, to understand whether smartphones can improve participation and attrition rates among this hard-to-reach group; and second, whether smartphone-based surveys can improve our understanding about health behaviors and statuses. To accomplish these objectives, McLanahan and Sugie 1) developed an open-source Android smartphone application to collect data; 2) recruited 156 participants and tracked their daily health experiences over three months; and 3) analyzed the detailed, person-day information using a variety of descriptive and statistical approaches. The study sample was men recently released from prison in Newark, New Jersey and participants were recruited based on a complete census of recent releases, in partnership with the New Jersey Parole Board.
Evaluation of Recursive Partitioning Methods for Measurement of Allostatic Load
PI: Christopher Seplaki, Princeton University
The theory of allostatic load provides a comprehensive framework that describes how emotional challenges and stressful events over the lifecourse exact a toll on multiple interrelated systems of the body and negatively affect health. Mechanisms driving this process include dysregulation of otherwise balanced interactions among diverse physiological systems (neuroendocrine, sympathetic nervous, immune, and cardiovascular) and metabolic pathways. Studies to date have linked measures of allostatic load that summarize dysregulation across these systems with indicators of health and mortality.
Considerable debate remains regarding how such multisystem dysregulation should be measured in population-based research. Existing summary measures of allostatic load combine a set of biological measures assessing diverse physiological systems associated with the stress response and incorporate a range of different structural assumptions. This pilot evaluated one existing strategy for measurement of allostatic load: recursive partitioning. The analyses used two sources of biodemographic data: the MacArthur Study of Successful Aging (MSSA), a community sample of high-functioning U.S. elderly; and the Social Environment and Biomarkers of Aging Study (SEBAS)7, a population-based sample of older Taiwanese. The goal of these analyses was to assess the relative strengths and weaknesses of the recursive partitioning approach in cross-sectional, longitudinal, within-sample, and out-of-sample contexts.
The Evolution of Age and Cohort Effects
PI: Sam Schulhofer-Wohl, Woodrow Wilson School, Princeton University; Co-PI: Yang Yang, University of Chicago
The aim of this project was to develop a new method for estimating age, period, and cohort (APC) effects that does not rely on the same assumptions of additivity embedded in conventional models, and to investigate the empirical performance of the new method.
A new way of modeling APC effects that defines cohort effects as an accumulation of age-by-period interactions was developed. Although a long-standing theoretical literature conceptualizes cohort effects in exactly this way, this model is the first to statistically operationalize the idea. The model is applied to analyze changes in age-specific mortality in Sweden over 150 years. This model fits the data dramatically better than the additive model and identifies two key aspects of mortality patterns that are not visible in an additive model. First, the rate of increase of mortality with age became more steep from 1881 to 1941. Second, the impact of early-life conditions on mortality lasts for several years but is unlikely to reach to old age.
This work produced a book chapter: “Modeling the Evolution of Age and Cohort Effects,” with Y. Claire Yang. In Dynamic Demographic Analysis: Key Contemporary Issues in Measuring and Modeling, ed. R. Schoen. The Netherlands: Springer, February 2016.
An Exploratory Study of the Occurrence of Pharmaceutical-Induced Aging Symptoms in the United States and in Brazil
PI: João Biehl, Princeton University; Co-Investigator: Mariana Socal, PhD Candidate, Johns Hopkins University
As the world’s population grows and lives longer, increasing scientific and medical attention has been given to natural and pathological aging processes and their possible prevention and treatment. This exploratory study was concerned with a significant, but largely understudied phenomenon: aging symptoms that are neither natural nor pathological, but induced by pharmaceuticals.
It is widely recognized that commonly used pharmaceutical treatments may produce adverse side effects. Adverse effects may range from isolated symptoms such as memory loss, gait imbalance, and muscle weakness (Cancelli et al., 2009; Edwards & Aronson, 2000; Moore & O'Keeffe, 1999) to severe conditions such as Parkinsonism or peripheral nerve disease (Barbosa, et al., 2006; Gaist, 2002). Pharmaceuticals may cause significant adverse effects even when prescribed for minor problems and in low doses. Anxiolytic drugs, for example, may cause cognitive impairment in as much as 68 percent of cases (Hindmarch et al., 2009). Cholesterol-lowering drugs may cause muscular weakness in up to 10 percent of cases and may also, if rarely, cause severe myopathy (Whayne, 2010). Although the pharmaceutically-induced origin of these conditions has been widely reported, the medical literature has yet to identify these conditions as a form of early aging. This acknowledgment is important in light of the expanding “pharmaceuticalization” of medical care and of public health initiatives throughout the developed and developing world (Biehl 2007; Petryna 2009). Pharmaceutically-induced pre-mature aging symptoms can be potentially reversed with proper diagnosis and management. But left unidentified, they may lead to unnecessary clinical testing, wrong diagnoses, and may also result in the harmful prescription of additional drugs.
Family Reunification and Older Immigrants: Implications for Health and Social Service Utilization
PI: Marta Tienda, Princeton University
This research proposed to examine the economic consequences of changes in the age composition of recent and established immigrants by year of arrival, pathway to senior status, and region of origin. Service utilization of foreign-born seniors—both near elderly (55-64) and elderly (65 and over)—were examined using several data sources: the New Immigrant Survey (wave 2); the Survey of Income and Program Participation; and as appropriate, the American Community Survey and Current Population Surveys. Each data source has different strengths and weaknesses, but collectively they allowed development of a comprehensive study of service utilization patterns of elderly immigrants by entry pathway and length of U.S. residence; region of origin; employment history/status; living arrangements; and personal attributes. This pilot was a feasibility study as a step for pursuing a more comprehensive study.
The short-term goals were:
- To become familiar with the data strengths and limitations in studying income and service utilization of foreign born elders;
- To develop a descriptive profile of recent and established older immigrants by year of arrival, pathway to senior status, and region of origin;
- To characterize the labor force and program participation of older immigrants by sponsorship as a senior vs. aging in situ statuses.
Genotyping and Psychosocial Phenotypes in MIDUS II
PIs: Burton Singer, Princeton University and Carol Ryff, University of Wisconsin
Singer worked with collaborators at the University of Wisconsin on gene-environment interactions in the MIDUS study. This research examined how genetic influences interact with macro-level social structural variables (age, gender, socioeconomic status, race/ethnicity), proximal psychosocial factors (e.g., well-being, personality traits, sense of control, social relationships, work/family life, community participation) and life challenges (daily stressors, chronic and acute events) to influence health and illness in an aging population. They initially conducted preliminary analyses using a small subsample of MIDUS respondents (n @ 110). They completed genotyping on a set of targeted Single Nucleotide Polymorphisms (SNPs) and microsatellites. DNA extraction and genotyping was carried out at the Biotechnology Center of the University of Wisconsin – Madison. Their choices of SNPs were guided by prior literature indicating their associations with biomarkers in MIDUS that had already been shown to be associated with social structural and psychosocial factors. They then engaged in association studies to relate the vectors of SNPs/Haplotypes, microsattelites, and VNTR classifications to vectors of psychosocial profiles and social structural conditions. In addition, Singer and his colleagues interrogated 10,000 SNPs using an Affymetrix GeneChip platform on approximately 50 of the MIDUS respondents, thereby ensuring full coverage of the genome.
Height, Health, Cognitive Ability and Aging
PI: Anne Case, Princeton University
The purpose of this pilot project is to begin research on the relationship between net nutrition in childhood and cognitive function in old age, using height as a marker for net nutrition. Height is examined as a possible determining factor associated with better cognitive function and slower cognitive decline as individuals age, and explore possible reasons for these associations. Documented differences included levels and changes in cognitive function across men and women of different heights, and examining whether associations between measures of adult socioeconomic status (as measured by education, earnings during the working years, and occupation) and cognitive function in old age can be accounted for by the common effects of net nutrition.
The research will rely primarily on data from the Health and Retirement Study, which has measures of cognitive ability over time for a number of years for cohort members. However, as part of this project, planning new research will be done collaboratively with the team of researchers who head the Helsinki Birth Cohort Study (HBCS). The HBCS collected detailed information on the growth of 20,436 children born between 1924 and 1944, as well as detailed social and economic information for these children as adults. An advantage of working with this data is that, while most of the other data sets covers only part of the life-span (e.g. from birth to middle age, or from late middle age into old age), the Helsinki cohort data cover the entire lifespan. The HBCS does not (yet) contain information on old-age cognitive ability. However, for men, it contains information on the results of cognitive tests taken by men at the time of military enlistment. For a subset of respondents, it provides information from examinations in old age on health and psychological functioning.
HIV Surveillance of Older Adults in Africa Centre Field Site in KwaZulu-Natal
PI: Anne Case, Princeton University
The goal of this project is to extend HIV surveillance to older adults in the Africa Centre field site in KwaZulu-Natal. Currently, the Africa Centre for Health and Population Studies is offering HIV tests to all adult women aged 15-49, and men aged 15-54, who are resident members of its field site (33,500 persons). Results from the first round of testing, which were completed in late 2004, indicate that a large fraction of women and men in early middle age are HIV positive. However, HIV rates remain high among those in late middle age as well: 20 percent of women aged 45 to 49, and 18 percent of men aged 50 to 54 were HIV positive. This pilot is extending surveillance to the population above ages 49 (for women) and 54 (for men). The research is motivated by several factors. It is essential for planning purposes that the public health community anticipates AIDS-related illness and ART delivery necessary for the older adults in this community. Understanding which older adults are at risk for HIV is also an important issue, which will influence the behavioral interventions planned. In addition, older adults are regarded as the pillars upon which children’s wellbeing will depend, after these children have lost parents to HIV/AIDS. If a significant fraction of the elderly is also HIV positive, the stability of household life is further threatened.
Household Economics, Wellbeing, and AIDS
PI: Anne Case, Princeton University
In this study, Dr. Case examined the impact of the AIDS crisis on the well-being of older South Africans, using data from panel surveys she conducted between 2002 and 2006 in four field sites in South Africa. With colleagues from the University of Cape Town and the University of Michigan, she has documented the role played by aging parents in caring for the children of children who die, and the extent to which older adults and their living children provide financial support to orphaned grandchildren. They find significant transfers of public and private funds to older adults in households with orphans, and no difference in expenditure patterns between older adult households with orphans and other older adult households. With respect to older adults’ quality of life, they find no effect of reporting that a child died, or of co-residence with orphaned grandchildren, on the older adults’ reports of depression, or on their self-assessed health (Ardington, Case, Islam et al 2009). Case also led a data collection effort at the Africa Centre for Health and Population Studies, in KwaZulu-Natal, in which caregivers for all deaths that occurred between January 2003 and December 2005 were interviewed about the costs associated with the deceased’s illness and the costs of the funeral. (Approximately half of all deaths in the demographic surveillance site over this period were due to AIDS.) Case and colleagues found that, on average, households spend the equivalent of a year’s income for an adult’s funeral, measured at median per capita African (Black) income. Approximately one-quarter of all individuals had some form of insurance, which helped surviving household members defray some fraction of funeral expenses. However, an equal fraction of households borrowed money to pay for the funeral. Households appear to respond to social pressure to bury their dead in a style consistent with the observed social status of the household and that of the deceased. Households that cannot afford a funeral commensurate with social expectations borrow money to pay for the funeral. Expensive funerals compromise the financial health of households, and Case subsequently found, in two demographic surveillance sites—Agincourt, in Limpopo Province, and at the Africa Centre—that surviving household members are poorer and have poorer affect, the greater the amount of money that was borrowed for the funeral.
Hunger & Decision Making
PIs: Eldar Shafir and Elizabeth Levy Paluck, Princeton University
The project set out to investigate the cognitive capacity and decision-making performance of people when they are hungry as compared to when they are not. In the first stage of our project, survey measures and behavioral tests were used in an attempt to gauge how hunger may affect self-control, cognitive control, reasoning, attention, and persistence on the tasks. The aim was to examine the effect of local hunger (e.g., having missed a meal or two) – not chronic starvation. The pilot studies were conducted with adult patrons at a Trenton soup kitchen (where food intake, or the lack thereof, proved too difficult to control), and with adults in Southern Sudan.
The eventual experimental design involved assigning 160 participants who had not eaten since the previous day to one of two conditions: a meal followed at an appropriate time by cognitive testing, and cognitive testing preceding (and later followed by) a meal. Participants in the meal-first condition were fed a meal, were invited to rest for one hour while watching a movie, listened to an educational radio show, and then completed a battery of paper-pencil cognitive tasks. Participants in the meal-last condition were invited to watch a movie for the same period of time as the first group, listened to an educational radio show, completed the battery of cognitive tasks, and then ate a meal provided by the research team.
Intertemporal Choice and Cognitative Control
PIs: Jonathan Cohen and Samuel McClure, Princeton University; Collaborators: George Loewenstein, Carnegie Mellon University and David Laibson, Harvard University
In Johnathon Cohen and Samuel McClure's previous work on intertemporal choice (Pilot #5 above; McClure et al., 2004) separate neural systems were identified that are differentially responsive to near-term and long-term primary (gustatory) and monetary rewards. The next step in the research was to begin investigating how behavior derives from the function of the b and d systems identified in these earlier studies. How do the b and d systems interact during decision making? This project investigates intertemporal choices between immediate rewards versus very long delayed rewards. Subjects were again asked to decide between two different outcomes: (1) viewing an alluring photograph (immediate reward) and (2) receiving money at a one month delay (long delay reward). This particular intertemporal decision problem had the advantageous new property of encouraging more protracted decision times in subjects. Because decision-making could persist for several seconds in this paradigm, the hope was to study in more detail the mechanisms that govern the online interaction between brain systems while the choice is being made (e.g. cognitive control). Unfortunately, pilot results were inconclusive, and Cohen and McClure determined that the photographs used for the immediate rewards were not nearly as effective a reward stimulus as juice had been for thirsty subjects in Pilot #5.
Mechanisms and Measurement of Motivated Taste Change
PI: Jason Riis, NYU and Sam McClure, Princeton University
Obesity is the second leading cause of preventable death in America (Mokdad et al., 2000). In addition, obesity is a risk factor for many chronic diseases including hypertension, heart disease, and some forms of cancer, and it was estimated to have an economic cost of $117 billion in 2000 (US Department of Health and Human Services, 2001).
Sugared sodas are thought to be one of the major contributors to the obesity epidemic (Popkin & Nielson, 2003), so one notable trend is in the beverage industry, where diet sodas have made considerable gains in market share over the last 4 years. The switch from regular Coke to Diet Coke is motivated by concerns about weight and health, but many Diet Coke drinkers report that they have come to prefer the taste of Diet Coke to regular Coke. This suggests that it is not willpower that is sustaining their preference for a healthier beverage, but rather, a change in the hedonic experience of consuming the healthier beverage. If taste change really is possible, it may be a much more sustainable route to behavior change than willpower.
Mortality, Income, Wealth and Rank in Academia
PI: Angus Deaton, PI, Princeton University
The broad aim of this project was to study the relationship between earnings, wealth and mortality, with a specific focus on whether relative income—measured alternatively as income relative to others within one’s department and within one’s University—is a determinant of mortality. This project examined this topic by merging records from the National Death Index (NDI) with the Faculty Retirement Survey (FRS). The FRS is a survey of more than 16,000 older academics at American colleges and Universities that contains information on each individual’s TIAA-CREF (Teachers Insurance and Annuity Association College Retirement Equity Fund) accumulation and salary and on the wealth and salaries of other professors in that individual’s department and institution. However, it contains no measures of health or mortality.
Neural Mechanisms Underlying Discounting
PI: Jonathan Cohen, Princeton University
The standard model of intertemporal choice that is used to study economic self-control, e.g., saving behavior and asset accumulation, assumes exponential discounting. However, there is growing evidence that humans systematically over-weight the value of immediate events (i.e. display hyperbolic discounting) and therefore make “short-sighted” decisions. This pilot study was concerned with understanding the neural mechanisms underlying discounting. Using functional magnetic resonance imaging (fMRI) we had previously demonstrated that the discounting of monetary rewards involves two separate brain systems (McClure et al., 2004, Science). One system is comprised of limbic brain regions associated with midbrain dopamine neurons and responds preferentially to rewards available in the immediate future (called the b system). The other system includes posterior parietal and lateral prefrontal cortex and responds equally to rewards at all delays (called the d system). This pilot project involved a follow-up study in which we studied time discounting for a fruit juice reward, delivered to thirsty participants inside the MRI scanner. In contrast to money, the immediate reward of fruit juice allowed us to study details of time discounting not possible with monetary reward. Therefore, the purposes of this project were: (1) to determine whether the b / d brain systems are involved in valuing primary biological rewards in addition to secondary rewards such as money; (2) to study the recruitment of the b system on a finer time scale, of minutes instead of weeks; and (3) to determine how behavioral preferences and choices correlate with levels of brain activity in limbic (b), prefrontal (d), and anterior cingulate cortex.
Non-invasive reproductive steroid hormone indicators of male and female aging in a highly social wild primate model: estrogens in males and testosterone in females
PI: Jeanne Altmann, Princeton University
This seeks to expand investigations of the physiology of aging to include novel studies of estrogens in males and testosterone in females. Estrogens and testosterone are present in both males and females but testosterone at higher levels in males than females and estrogens exhibit the opposite sex difference. Age changes in concentrations of the more common reproductive hormone found in each sex are well documented in humans. In contrast, the patterns in each sex for the less common reproductive hormones during aging are not well understood and the functional consequences of age changes are even less so. This project seeks to further validate noninvasive measurement of these hormones and exploration of their patterns during aging in a wild primate model using fecal samples.
Novel longitudinal observational health indicators in a highly social wild primate model
PI: Jeanne Altmann, Princeton University; Co-PI: Susan Alberts, Duke University
This study aimed to establish noninvasive health indicators in a naturally aging population of nonhuman primates, the baboons of the Amboseli basin in southern Kenya. Altmann collaborated with Susan Alberts, the Robert F. Durden Professor of Biology at Duke University; Altmann and Alberts together direct the Amboseli Baboon Research Project (ABRP). The ABRP data collection relies largely on non-invasive, purely observational methods. These include observational data on behavior and life history, as well as collection of fecal samples for the extraction of DNA and of steroid hormone metabolites (full bibliography and most data collection protocols can be found at https://amboselibaboons.nd.edu). Altmann and her collaborators took advantage of and build on their existing long-term database of almost unprecedented breadth and depth of non-invasively collected data on this population, which has been under continuous observation for 35 years. Extensive life history and behavioral data have been collected on individually identified animals throughout their natural life spans. They will work to enhance these existing survival analyses with what we believe is the first detailed, simultaneous longitudinal analysis of change with age in multiple health indicators in a wild nonhuman primate.
Scarcity, Cognitive Function, and Stress
PI: Eldar Shafir, Princeton University
This project investigates central aspects of the psychology of scarcity, a novel theoretical framework that looks at some of the psychological challenges faced by people living in poverty, and the behavioral patterns that ensue. Perhaps the defining property of being poor is that money is scarce; there is not enough of it to meet the demands imposed by daily life. One important corollary of monetary scarcity is the persistent need to think about tradeoffs: to compute the budgetary consequences of even small financial decisions (“If I purchase X, what will I not be able to purchase instead?”). This, we posit, yields a demanding and ever-present set of cognitive challenges that are encountered considerably less frequently in the lives of those who are financially more comfortable. The chronic challenges of tradeoff thinking, we suggest, may help explain the greater planning and decision difficulties, including health and financial troubles, so frequently exhibited by the poor, particularly as they age.
Social Status and Health over the Life Course: Evidence from the Whitehall II Study
PIs: Anne Case and Christina Paxson, Princeton University
The purpose of this pilot was to examine the extent to which early life health and environment among British civil servants, followed over time in the Whitehall II panel study (WII), can explain their health and socioeconomic status in late-middle age and old age. Life experiences are examined—as measured by adult height, as well as retrospective information on childhood socioeconomic status and health—influence economic outcomes (income, asset holdings, employment grade) and health (chronic conditions, difficulties with activities of daily living, self-assessed health, and mental health) among Whitehall participants. Using several British cohort studies, our earlier research found that taller individuals attain higher levels of education, sort into higher grade occupations, and have higher levels of full-time employment and earnings. The associations between height and labor market outcomes are largely due to the correlation of height and cognitive ability. Using the wealth of information on cognitive function, health outcomes, and labor market outcomes in the Whitehall data, analyses are conducted of how height and early-life health is related to trajectories of labor market outcomes, and quantify the extent to which the relationship between height and labor market outcomes is due to education, cognitive function and adult health.
Comparisons are made with the height, cognitive function and labor market profiles of Whitehall civil servants with members of two British birth cohorts (the National Child Development Study, NCDS 1958, and British Cohort Study, BCS 1970. Members of the NCDS and BCS have been followed by birth to middle age. These data, upon registration, are publically available. This studies whether the correlations between their heights, cognitive function and labor market outcomes among members of these birth cohorts look similar to those found among cohort members in WII, and whether information about childhood SES and family background in the NCDS and BCS offer potential insights for the Whitehall II cohort members, for whom only a limit set of family background variables are available.
Strategies for Exploration in Human Decision Making
PI: Jonathan Cohen, Princeton University
This pilot project examined the strategies that people use for deciding when to explore and gain new information about their environments. In earlier pilot work, older people explored less than they should, even when the exploratory behavior was clearly adaptive. Here, the factors that determined this pattern of exploratory decision-making in a population of young adults were characterized.
A new task was developed that allowed exploration to be assessed in an environment with multiple options. In the task, people selected between three boxes, each of which yielded points; these points were converted to money at the end of the task. On each round, participants were given some information about each of the boxes (sample outcomes below the box) and told how many choices they had left to make (coins on the top right). One box always had 3 samples, and the other two always had one sample (one higher and one lower). This design assessed the strategy people would use to explore such an environment. Selection of the option with a single high-valued sample would represent directed information seeking for the next best possible option, whereas selection of the option with a single low-valued sample would represent random information seeking. Based on theoretical work (Wilson et al., 2014), these two factors (directed and random) were expected to be the primary drivers of exploration.
Using Behavior Economics to Understand Uptake in Employee Benefits Programs
PIs: Eldar Shafir, Princeton University and Janet Schwartz (Postdoctoral Research Associate) Princeton University
This research combined field and laboratory experiments to examine the psychological processes underlying decisions in the healthcare marketplace across the lifespan. In particular the research focused on (1) how the unique features of the healthcare marketplace shape people’s attitudes and behaviors and (2) psychological influences on the design and take-up of health related benefits.
Although the principles of decision science have shown great power in laboratory settings, policy makers and managers have largely ignored them in designing and marketing actual policy. One example is employer-sponsored Flexible Spending Accounts (FSAs). FSAs offer workers tax relief on out-of-pocket healthcare expenses, but not without transaction costs and risk. Standard economic models assume that FSA participation decisions reflect a rational calculus of the program’s costs and benefits. This assumption, however, fails to capture the boundedly rational nature of most decision making, which is often guided (or misguided) by nuanced and normatively irrelevant features. And misguided assumptions of this kind may prove to have substantial welfare implications. Thus, one of our initial research questions was whether typically low FSA take-up rates reflected a rational decision not to participate or reflected a lack of awareness and bias.