Individual and Community level Developmental Adversities: Associations with Marijuana and Alcohol Use in Late-Adolescents and Young Adults

Exposure to community and individual level stressors during adolescence has been reported to be associated with increased substance use. However, it remains unclear what the relative contribution of different community- and individual-level factors play when alcohol and marijuana use become more prevalent during late adolescence. The present study uses a large longitudinal sample of adolescents (Wave 1: N = 2017; 55% Female; 54.5% White, 22.3% Black, 8% Hispanic, 15% other) to evaluate the association and potential interactions between community- and individual-level factors and substance use from adolescence to young adulthood (Wave 1 to Wave 3 Age Mean [SD]: 16.7 [1.1], 18.3 [1.2], 19.3 [1.2]). Across three waves of data, multilevel modeling (MLM) is used to evaluate the association between community affluence and disadvantage, individual household socioeconomic status (SES, measured as parental level of education and self-reported public assistance) and self-reported childhood maltreatment with self-reported 12-month alcohol and 12-month marijuana use occasions. Sample-selection weights and attrition-adjusted weights are accounted for in the models to evaluate the robustness of the estimated effects. Across the MLMs, there is a significant positive association between community affluence and parental education with self-reported alcohol use but not self-reported marijuana use. In post hoc analyses, higher neighborhood affluence in older adolescents is associated with higher alcohol use and lower use in younger adolescents; the opposite association is found for neighborhood disadvantage. Consistent with past literature, there is a significant positive association between self-reported childhood maltreatment and self-reported 12-month alcohol and 12-month marijuana use. Results are largely consistent across weighted and unweighted analyses, however, in weighted analyses there is a significant negative association between community disadvantage and self-reported 12-month alcohol use. This study demonstrates a nuanced relationship between community- and individual-level factors and substance use during the transitional window of adolescence which should be considered when contextualizing and interpreting normative substance use during adolescence.

Maternal education prospectively predicts child neurocognitive function: An environmental influences on child health outcomes study

A large body of research has established a relation between maternal education and children's neurocognitive functions, such as executive function and language. However, most studies have focused on early childhood and relatively few studies have examined associations with changes in maternal education over time. Consequently, it remains unclear if early maternal education is longitudinally related to neurocognitive functions in children, adolescents, and young adults. In addition, the associations between changes in maternal education across development and more broadly defined neurocognitive outcomes remain relatively untested. The current study leveraged a large multicohort sample to examine the longitudinal relations between perinatal maternal education and changes in maternal education during development with children's, adolescents', and young adults' neurocognitive functions (N = 2,688; Mage = 10.32 years; SDage = 4.26; range = 3-20 years). Moreover, we examined the differential effects of perinatal maternal education and changes in maternal education across development on executive function and language performance. Perinatal maternal education was positively associated with children's later overall neurocognitive function. This longitudinal relation was stronger for language than executive function. In addition, increases in maternal education were related to improved language performance but were not associated with executive functioning performance. Our findings support perinatal maternal education as an important predictor of neurocognitive outcomes later in development. Moreover, our results suggest that examining how maternal education changes across development can provide important insights that can help inform policies and interventions designed to foster neurocognitive development. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Personalized Neural Networks Underlie Individual Differences in Ethnic Identity Exploration and Resolution

This study examined how ethnic identity relates to large-scale brain networks implicated in social interactions, social cognition, self-definition, and cognitive control. Group Iterative Multiple Model Estimation (GIMME) was used to create sparse, person-specific networks among the default mode and frontoparietal resting-state networks in a diverse sample of 104 youths aged 17-21. Links between neural density (i.e., number of connections within and between these networks) and ethnic identity exploration and resolution were evaluated in the full sample. Ethnic identity resolution was positively related to frontoparietal network density, suggesting that having clarity about one's ethnic group membership is associated with brain network organization reflecting cognitive control. These findings help fill a critical knowledge gap about the neural underpinnings of ethnic identity.

Neural heterogeneity underlying late adolescent motivational processing is linked to individual differences in behavioral sensation seeking

Adolescent risk-taking, including sensation seeking (SS), is often attributed to developmental changes in connectivity among brain regions implicated in cognitive control and reward processing. Despite considerable scientific and popular interest in this neurodevelopmental framework, there are few empirical investigations of adolescent functional connectivity, let alone examinations of its links to SS behavior. The studies that have been done focus on mean-based approaches and leave unanswered questions about individual differences in neurodevelopment and behavior. The goal of this paper is to take a person-specific approach to the study of adolescent functional connectivity during a continuous motivational state, and to examine links between connectivity and self-reported SS behavior in 104 adolescents (M_Age  = 19.3; SD_Age  = 1.3). Using Group Iterative Multiple Model Estimation (GIMME), person-specific connectivity during two neuroimaging runs of a monetary incentive delay task was estimated among 12 a priori brain regions of interest representing reward, cognitive, and salience networks. Two data-driven subgroups were detected, a finding that was consistent between both neuroimaging runs, but associations with SS were only found in the first run, potentially reflecting neural habituation in the second run. Specifically, the subgroup that had unique connections between reward-related regions had greater SS and showed a distinctive relation between connectivity strength in the reward regions and SS. These findings provide novel evidence for heterogeneity in adolescent brain-behavior relations by showing that subsets of adolescents have unique associations between neural motivational processing and SS. Findings have broader implications for future work on reward processing, as they demonstrate that brain-behavior relations may attenuate across runs.

Ecological stress, amygdala reactivity, and internalizing symptoms in preadolescence: Is parenting a buffer?

Ecological stress during adolescent development may increase the sensitivity to negative emotional processes that can contribute to the onset and progression of internalizing behaviors during preadolescence. Although a small number of studies have considered the link among the relations between ecological stress, amygdala reactivity, and internalizing symptoms in childhood and adolescence, these studies have largely been small, cross-sectional, and often do not consider unique roles of parenting or sex. In the current study, we evaluated the interrelations between ecological stress, amygdala reactivity, subsequent internalizing symptoms, and the moderating roles of parenting and sex among 9- and 10-year-old preadolescents from the Adolescent Brain Cognitive Development (ABCD) Study ®. A subset of participants who met a priori quality control criteria for bilateral amygdala activation during the EN-back faces versus places contrast (N = 7,385; Mean Age = 120 months, SD = 7.52; 49.5% Female) were included in the study. A confirmatory factor analysis was performed to create a latent variable of ecological stress, and multiple structural equation models were tested to evaluate the association among baseline ecological stress and internalizing symptoms one year later, the mediating role of amygdala reactivity, and moderating effects of parental acceptance and sex. The results revealed a significant association between ecological stress and subsequent internalizing symptoms, which was greater in males than females. There was no association between amygdala reactivity during the Faces versus Places contrast and ecological stress or subsequent internalizing symptoms, and no mediating role of amygdala or moderating effect of parental acceptance on the association between ecological stress and internalizing symptoms. An alternative mediation model was tested which revealed that there was a small mediating effect of parental acceptance on the association between ecological stress and internalizing symptoms, demonstrating lower internalizing symptoms among preadolescents one year later. Given the lack of association in brain function, ecological stress and internalizing symptoms in preadolescents in this registered report, effects from comparable small studies should be reconsidered in larger samples.

Interactions between methodological and interindividual variability: How Monetary Incentive Delay (MID) task contrast maps vary and impact associations with behavior

INTRODUCTION

Phenomena related to reward responsiveness have been extensively studied in their associations with substance use and socioemotional functioning. One important task in this literature is the Monetary Incentive Delay (MID) task. By cueing and delivering performance-contingent reward, the MID task has been demonstrated to elicit robust activation of neural circuits involved in different phases of reward responsiveness. However, systematic evaluations of common MID task contrasts have been limited to between-study comparisons of group-level activation maps, limiting their ability to directly evaluate how researchers' choice of contrasts impacts conclusions about individual differences in reward responsiveness or brain-behavior associations.

METHODS

In a sample of 104 participants (Age Mean = 19.3, SD = 1.3), we evaluate similarities and differences between contrasts in: group- and individual-level activation maps using Jaccard's similarity index, region of interest (ROI) mean signal intensities using Pearson's r, and associations between ROI mean signal intensity and psychological measures using Bayesian correlation.

RESULTS

Our findings demonstrate more similarities than differences between win and loss cues during the anticipation contrast, dissimilarity between some win anticipation contrasts, an apparent deactivation effect in the outcome phase, likely stemming from the blood oxygen level-dependent undershoot, and behavioral associations that are less robust than previously reported.

CONCLUSION

Consistent with recent empirical findings, this work has practical implications for helping researchers interpret prior MID studies and make more informed a priori decisions about how their contrast choices may modify results.

Conceptualizing protective family context and its effect on substance use: Comparisons across diverse ethnic-racial youth

Background: Although family behaviors are known to be important for buffering youth against substance use, research in this area often evaluates a particular type of family interaction and how it shapes adolescents' behaviors, when it is likely that youth experience the co-occurrence of multiple types of family behaviors that may be protective. Methods: The current study (N = 1716, 10th and 12th graders, 55% female) examined associations between protective family context, a latent variable comprised of five different measures of family behaviors, and past 12 months substance use: alcohol, cigarettes, marijuana, and e-cigarettes. Results: A multi-group measurement invariance assessment supported protective family context as a coherent latent construct with partial (metric) measurement invariance among Black, Latinx, and White youth. A multi-group path model indicated that protective family context was significantly associated with less substance use for all youth, but of varying magnitudes across ethnic-racial groups. Conclusion: These results emphasize the importance of evaluating psychometric properties of family-relevant latent variables on the basis of group membership in order to draw appropriate inferences on how such family variables relate to substance use among diverse samples.

Cortical and subcortical response to the anticipation of reward in high and average/low risk-taking adolescents

Since the first neurodevelopmental models that sought to explain the influx of risky behaviors during adolescence were proposed, there have been a number of revisions, variations and criticisms. Despite providing a strong multi-disciplinary heuristic to explain the development of risk behavior, extant models have not yet reliably isolated neural systems that underlie risk behaviors in adolescence. To address this gap, we screened 2017 adolescents from an ongoing longitudinal study that assessed 15-health risk behaviors, targeting 104 adolescents (Age Range: 17-to-21.4), characterized as high-or-average/low risk-taking. Participants completed the Monetary Incentive Delay (MID) fMRI task, examining reward anticipation to "big win" versus "neutral". We examined neural response variation associated with both baseline and longitudinal (multi-wave) risk classifications. Analyses included examination of a priori regions of interest (ROIs); and exploratory non-parametric, whole-brain analyses. Hypothesis-driven ROI analysis revealed no significant differences between high- and average/low-risk profiles using either baseline or multi-wave classification. Results of whole-brain analyses differed according to whether risk assessment was based on baseline or multi-wave data. Despite significant mean-level task activation, these results do not generalize prior neural substrates implicated in reward anticipation and adolescent risk-taking. Further, these data indicate that whole-brain differences may depend on how risk-behavior profiles are defined.

Adolescent substance use and functional connectivity between the ventral striatum and hippocampus

Neurodevelopmental explanations for adolescent substance use have focused on heightened sensitivity of mesolimbic circuitry, centered on the ventral striatum (VS). Recent evidence suggests that, relative to adults, adolescents show a stronger link between reinforcement learning and episodic memory for rewarding outcomes and greater functional connectivity between the VS and hippocampus, which may reflect a heightened reward modulation of memory. However, a link between VS-hippocampal circuitry and adolescent substance use has yet to be established. Two separate studies were conducted to evaluate whether variation in VS-hippocampal resting-state functional connectivity (rs-FC) predicts subsequent adolescent substance use exposure. A pilot study (Study 1) was conducted in 19 youth recruited from a high sociodemographic risk population (N = 19; mean age = 13.3 SD = 1.4; 14 females; 47% Black Non-Hispanic, 32% White Non-Hispanic). To replicate results of Study 1, Study 2 utilized data from the National Consortium on Adolescent Neurodevelopment and Alcohol (N = 644; mean age = 16.3 SD = 2.5; 339 females; 11% Black Non-Hispanic, 11% Hispanic/Latino, 66% White Non-Hispanic). Resting-state fMRI data were collected at a baseline time point and lifetime and past year self-reported substance use was collected at a follow up visit. Regression models tested whether baseline VS-hippocampal rs-FC predicted substance use exposure at follow up, as measured by an index score reflecting the number of substance classes (e.g., alcohol, marijuana) tried and overall frequency of use. Across both studies, higher VS-hippocampal rs-FC at baseline predicted greater substance use exposure at follow up (pFWE < 0.05). These data provide the first evidence linking increased VS-hippocampal connectivity with greater adolescent substance use exposure. Results fit with the emerging idea that variation in adolescent substance use may relate to not only individual differences in mesolimbic sensitivity to reward, but also to an individuals' memory sensitivity to reward as measured by connectivity between canonical memory and reward regions.

Adolescent Health Risk Behaviors: Convergent, Discriminant and Predictive Validity of Self-Report and Cognitive Measures

Self-report and cognitive tasks of reward sensitivity and self-regulation have influenced several developmental models that may explain the heightened engagement in risk behaviors during adolescence. Despite some inconsistencies across studies, few studies have explored the convergent, discriminant, and predictive validity of self-report and cognitive measures of these psychological characteristics in adolescence. The present study evaluated the convergent and discriminant validity of self-report and cognitive measures of reward sensitivity and self-regulation among 2017 adolescents (age M = 16.8, SD = 1.1; 56% female; 55% White, 22% Black, 8% Hispanic, 15% other race/ethnic; 49% 10th grade and 51% 12th grade). This study compared the predictive validity of an omnibus measure and specific measures of risk engagement. Convergent and discriminant validity from self-report to cognitive tasks were as predicted, although with weak convergent relationships. As hypothesized, compared to cognitive tasks, self-report measures consistently predicted risky behaviors and explained more variance in the models. These results demonstrate that while cognitive tasks can significantly predict certain risk behaviors, they require increased power to find the very small effects, raising questions about their use as implicit proxies for real world risk behavior.

Social Inequality in Population Developmental Health: An Equity and Justice Issue

The conceptual framework for this chapter focuses on outcomes in developmental health as a key indicator of equity. Not all disparities in developmental health are indicators of a failure of equity and justice, but those that are clearly linked to social patterns in theoretically coherent and empirically substantial ways serve as a powerful diagnostic tool. They are especially diagnostic when they point to social factors that are remediable, especially in comparison to societies in which such social disparities are sharply lower (Keating, Siddiqi, & Nguyen, 2013). In this chapter, I review the theoretical links and empirical evidence supporting this central claim and propose that there is strong evidence for the following critical links: (a) there is a compelling empirical connection between disparities in social circumstances and disparities in developmental health outcomes, characterized as a social gradient effect; (b) "drilling down" reveals the core biodevelopmental mechanisms that yield the social disparities that emerge across the life course; (c) in turn, life course effects on developmental health have an impact on societies and populations that are revealed by "ramping up" the research to consider international comparisons of population developmental health; and (d) viewing this integrated evidence through the lens of equity and justice helps to break the vicious cycle that reproduces social inequality in a distressingly recurring fashion.

Pregnancy recruitment for population research: the National Children's Study vanguard experience in Wayne County, Michigan

BACKGROUND

To obtain a probability sample of pregnancies, the National Children's Study conducted door-to-door recruitment in randomly selected neighbourhoods in randomly selected counties in 2009-10. In 2011, an experiment was conducted in 10 US counties, in which the two-stage geographic sample was maintained, but participants were recruited in prenatal care provider offices. We describe our experience recruiting pregnant women this way in Wayne County, Michigan, a county where geographically eligible women attended 147 prenatal care settings, and comprised just 2% of total county pregnancies.

METHODS

After screening for address eligibility in prenatal care offices, we used a three-part recruitment process: (1) providers obtained permission for us to contact eligible patients, (2) clinical research staff described the study to women in clinical settings, and (3) survey research staff visited the home to consent and interview eligible women.

RESULTS

We screened 34,065 addresses in 67 provider settings to find 215 eligible women. Providers obtained permission for research contact from 81.4% of eligible women, of whom 92.5% agreed to a home visit. All home-visited women consented, giving a net enrolment of 75%. From birth certificates, we estimate that 30% of eligible county pregnancies were enrolled, reaching 40-50% in the final recruitment months.

CONCLUSIONS

We recruited a high fraction of pregnancies identified in a broad cross-section of provider offices. Nonetheless, because of time and resource constraints, we could enrol only a fraction of geographically eligible pregnancies. Our experience suggests that the probability sampling of pregnancies for research could be more efficiently achieved through sampling of providers rather than households.

A Comparative Study of Population Health in the United States and Canada during the Neoliberal Era, 1980–2008

This article draws on the vast evidence that suggests, on one hand, that socioeconomic inequalities in health are present in every society in which they have been measured and, on the other hand, that the size of inequalities varies substantially across societies. We conduct a comparative case study of the United States and Canada to explore the role of neoliberalism as a force that has created inequalities in socioeconomic resources (and thus in health) in both societies and the roles of other societal forces (political, economic, and social) that have provided a buffer, thereby lessening socioeconomic inequalities or their effects on health. Our findings suggest that, from 1980 to 2008, while both the United States and Canada underwent significant neoliberal reforms, Canada showed more resilience in terms of health inequalities as a result of differences in: ( a) the degree of income inequality, itself resulting from differences in features of the labor market and tax and transfer policies, ( b) equality in the provision of social goods such as health care and education, and ( c) the extent of social cohesiveness across race/ethnic- and class-based groups. Our study suggests that further attention must be given to both causes and buffers of health inequalities.

Cost-Benefit Analysis Mediation of the Relationship Between Sensation Seeking and Risk Behavior

Risk behavior during adolescence results in substantial morbidity and mortality. Sensation seeking consistently relates to engagement in risk behavior, but the psychological mediators of this relationship remain unclear. The current study demonstrates that adolescents' judgments of the costs versus benefits of risk behavior were a significant mediator of this relationship. Participants were 406 racially and ethnically diverse adolescents ages 12-17 (M = 14.5, SD = 1.7; 48.3% female) who participated in a larger multi-site investigation of personality and neurocognitive predictors of risk behavior. Data were collected via self-report in a single laboratory session. Mediation of the relationship of sensation seeking to risk behavior was tested using structural equation modeling. Results indicated that higher levels of sensation seeking predicted weighing the benefits of risk behavior higher than its costs, which in turn predicted higher levels of risk behavior. Implications of these findings for understanding mechanisms underlying adolescents' risk behavior and directions for future research are discussed.

Adolescent drivers: a developmental perspective on risk, proficiency, and safety

Despite considerable improvement in the rates of crashes, injuries, and fatalities among adolescent drivers, attributable in part to effective interventions such as graduated driver licensing, these rates and their associated health risks remain unacceptably high. To understand the sources of risky driving among teens, as well as to identify potential avenues for further advances in prevention, this article presents a review of the relevant features of contemporary research on adolescent development. Current research offers significant advances in the understanding of the sources of safe driving, proficient driving, and risky driving among adolescents. This multifaceted perspective--as opposed to simple categorization of good versus bad driving--provides new opportunities for using insights on adolescent development to enhance prevention. Drawing on recent work on adolescent physical, neural, and cognitive development, we argue for approaches to prevention that recognize both the strengths and the limitations of adolescent drivers, with particular attention to the acquisition of expertise, regulatory competence, and self-regulation in the context of perceived risk. This understanding of adolescent development spotlights the provision of appropriate and effective scaffolding, utilizing the contexts of importance to adolescents--parents, peers, and the broader culture of driving--to support safe driving and to manage the inherent risks in learning to do so.

Understanding adolescent development: implications for driving safety

PROBLEM

The implementation of Graduated Driver Licensing (GDL) programs has significantly improved the crash and fatality rates of novice teen drivers, but these rates remain unacceptably high.

METHOD

A review of adolescent development research was undertaken to identify potential areas of improvement.

RESULTS

Research support for GDL was found to be strong, particularly regarding early acquisition of expertise in driving safety (beyond driving skill), and to limitations that reduce opportunities for distraction. GDL regimes are highly variable, and no US jurisdictions have implemented optimal regimes.

SUMMARY

Expanding and improving GDL to enhance acquisition of expertise and self-regulation are indicated for implementation and for applied research. Driver training that effectively incorporates safety goals along with driving skill is another target.

IMPACT ON INDUSTRY

The insurance industry will benefit from further GDL enhancements. Benefits may accrue to improved driver training, improved simulation devices during training, and automated safety feedback instrumentation.

Young children's social information processing: Family antecedents and behavioral correlates

Little research has examined whether social information processing (SIP) measures from early childhood predict externalizing problems beyond the shared association with familial risk markers. In the present study, family antecedents and first-grade externalizing behaviors were studied in relation to preschool and 1st-grade SIP using data from the U.S. National Institute for Child Health and Human Development Study of Early Child Care (N=1,364). A subgroup of low-risk children reported only benign attributions in preschool and had few externalizing problems in 1st grade according to both teacher and mother reports. After controlling for gender and cognitive functioning, the authors found that maternal education and authoritarian attitudes were key predictors of this "Pollyanna preschooler" status and of SIP in 1st grade. However, small effect sizes for SIP variables underscore the need for new approaches to measurement and for further research on moderators of the link between SIP and children's behavior.

Adolescents' and children's knowledge about rights: some evidence for how young people view rights in their own lives

The present study examined the development of knowledge about rights from childhood to adolescence. One hundred and sixty-nine 8-16-year-olds participated in individual semi-structured interviews assessing knowledge and importance of rights both generally and in children's and adolescents' lives. Detailed content analyses indicated that a global stage account may not capture key features of the development of young people's knowledge about rights. Even the oldest adolescents consistently "defined" rights in concrete rather than abstract terms. In contrast, by 10 years of age the majority of subjects were aware of the universal nature of rights. These results suggest that what adolescents and children think about rights appears to be influenced by how they view rights in their own lives. The findings are discussed in terms of developmental theory and in relation to practical implications for children's rights.

Children's and adolescents' understanding of rights: balancing nurturance and self-determination

This study examined the development of young people's understanding of nurturance and self-determination rights. One hundred and sixty-nine participants from 5 age groups (8, 10, 12, 14, and 16 years of age) participated in a semistructured interview containing hypothetical vignettes, in which a story character wished to exercise a self-determination right or nurturance right that conflicted with the wishes or practices of those in authority. Participants were asked to decide if they would support the story character's request for rights and to justify their decisions. Younger children (8- to 12-year-olds) were significantly less likely to identify both nurturance and self-determination rights as salient than were older participants (14- to 16-year-olds). The types of reasoning participants exhibited for the two types of rights differed at all ages. Reasoning about nurturance rights did not show an age-related progression from concrete to abstract, whereas reasoning about self-determination rights was more likely to exhibit such a progression. Results suggest that previous attempts to explain the development of understanding of rights in terms of global stages does not fully capture children's and adolescents' reasoning, and, in particular, such a framework may not account for the differences in young people's thinking about the 2 types of rights.

Blurring of vessels in spiral CT angiography: effects of collimation width, pitch, viewing plane, and windowing in maximum intensity projection

PURPOSE

Our goal was to examine the effects of collimation width (CW), pitch, viewing plane, and windowing on the display of in-plane vessels in maximum intensity projection (MIP).

METHOD

A theoretical concept based on partial volume averaging of vessels was developed to describe the contents of voxels (densities) in MIP and to derive cross-sectional vessel diameters and blurring. To validate the concept and to describe the influence of pitch, a Plexiglas cone submerged in water was scanned with varying CW and pitch. Binary MIP with three representative window levels was chosen so that definitive vessel diameters could be quantitated.

RESULTS

The theoretical concept correctly predicted voxel contents and blurring for CW > or = 3 mm and low pitch. For high pitch, actual blurring was larger; however, for a given table speed, blurring of the cone decreased with pitch while increasing with CW. Overall blurring was most effectively reduced by using a thin CW and the transverse viewing plane. In the transverse viewing plane, the least blurring was found using binary MIP with a low window level. On the contrary, in the longitudinal viewing plane, blurring was minimized using a window level halfway between the density of the cone and that of the surrounding water.

CONCLUSION

For CW > or = 3 mm, blurring of in-plane vessels can be explained with a simple geometrical concept based on partial volume. For accurate display, the transverse viewing plane should be used, a proper windowing must be chosen, and the CW should be kept below vessel size while raising the pitch to cover a reasonable volume.

Cultural specificity of support sources, correlates and contexts: three studies of African-American and caucasian youth

Levels and correlates of parental support, peer support, partner support, and/or spiritual support among African American and Caucasian youth were examined in three contexts: adolescent pregnancy (Study 1), first year of college (Study 2), and adolescence and young adulthood (age 15-29; Study 3). Partially consistent with a cultural specificity perspective, in different contexts different support sources were higher in level and/or more strongly related to adjustment for one ethnic group than the other. Among pregnant adolescents, levels of spiritual support were higher for African Americans than Caucasians; additionally, peer support was positively related to well-being only for African Americans whereas partner support was positively related to well-being only for Caucasians. Among college freshmen, family support was more strongly related to institutional and goal commitment for African Americans than Caucasians; conversely, peer support was more strongly related to institutional and goal commitment among Caucasians. Among 15 to 29-year-olds, levels of parental support and spiritual support were higher among African Americans than Caucasians; additionally, spiritual support was positively related to self-esteem for African Americans but not for Caucasians. Implications and limitations of the research are discussed.

Infrarenal abdominal aortic aneurysms: implications of CT evaluation of size and configuration for placement of endovascular aortic grafts

PURPOSE

To measure infrarenal abdominal aortic aneurysms and assess the implications and potential obstacles for placement of an endovascular aortic graft undergoing clinical testing in Europe.

MATERIALS AND METHODS

Helical computed tomography was used to measure 77 infrarenal aortic aneurysms (77 patients) and the distances between the aneurysms and the renal arteries and the aortic bifurcation.

RESULTS

Mean length of the aneurysms was 8.2 cm; mean distance to the renal arteries, 2.7 cm; mean aortic diameter 1.5 cm distal to the renal arteries, 1.9 cm; and mean minimal diameter of perfused lumen, 2.5 cm. Thirteen aneurysms extended into the common iliac artery; 40 reached the bifurcation. The mean minimal luminal diameter of the iliac artery was 1.1 cm.

CONCLUSION

Sufficient nonaneurysmal segments below the renal arteries and distal to the aneurysms are necessary for stent fixation. The large diameter of the delivery introducer in relation to the iliac arteries may be a major obstacle to graft delivery. At best, 33 patients could have benefited from use of the graft evaluated.

On estimating processing variance: commentary and reanalysis of Kail's "Developmental functions for speeds of cognitive processes"

A recent paper by Kail (1988) in this journal appears to contain a significant error in the data analysis. The "goodness-of-fit" coefficients reported which suggest that overall about 94% of the variance can be accounted for by the model seem to be a substantial overestimation as a result of inappropriate procedures for statistical modeling. Using the data made available to us by Kail, we have reanalyzed these results. The corrected values range from 0.9 to 92.1% for the individual tasks with an overall average between 40 and 60%. We suggest that the support for the original conclusions is considerably weaker than reported.

Differences in memory retrieval: a construct validity investigation

Long-term memory retrieval efficiency was investigated as a potential underlying source of individual and developmental differences in cognitive functioning. Fourth-grade, eighth-grade, and college-aged subjects participated in a task using the Posner letter-matching paradigm. Letter pairs were presented simultaneously under physical-match and name-match instruction conditions. Reaction times were used to estimate parameters of long-term memory retrieval efficiency, basic encoding, decision, and response time, and name and physical output interference. Psychometric tests of verbal and spatial ability were included to assess convergent and discriminant validity of hypothesized relationships between aptitude test performance and basic cognitive processes. Developmental differences were observed in most but not all of the processing variables. Individual difference analyses indicated that less confounded estimates of processing parameters were not systematically related to verbal ability at any age level. Basic encoding and response speed was the most consistent correlate of spatial ability. The results suggest difficulties in previous interpretations of NIPI-verbal ability relationships. The study of cognitive processes in interaction and embedded in meaningful tasks is discussed.

Perception of numerical invariance in neonates

40 healthy, normal newborn infants were evaluated with reference to their ability to discriminate among visual stimulus arrays consisting of 2 versus 3 or 4 versus 6 black dots. Infants made this discrimination within a habituation/dishabituation paradigm for the small number sets (2 to 3 and 3 to 2) but not for the larger sets (4 to 6 and 6 to 4). We argue that this suggests the ability to abstract numerical invariance from small-set visual arrays and may be evidence for complex information processing during the first week of life.

Development of the search-processing parameter

A potentially important source of cognitive developmental variance is that associated with basic cognitive-processing efficiency. Discrepant findings from several studies have failed to establish convincingly whether developmental change exists in basic processing efficiency. Employing 2 different experimental tasks, memory and visual scanning, which permit the isolation of a theoretically similar process, that is, search, we examined age effects on the search-processing parameter after analyzing it for convergent and discriminant validity. Each of the 96 subjects at 4 ages (9, 11, 13, and 15 years) completed both experiments. Validity evidence was obtained through a comparison of process and task intercorrelations, which revealed the former to be significantly more related than the latter (p less than .001). Also, significant age effects (p less than .001) were obtained for the search-processing parameter in both tasks, which provides evidence for the development of basic cognitive-processing efficiency.