On the empirical indistinguishability of knowledge structures

In recent years a number of articles have focused on the identifiability of the basic local independence model. The identifiability issue usually concerns two model parameter sets predicting an identical probability distribution on the response patterns. Both parameter sets are applied to the same knowledge structure. However, nothing is known about cases where different knowledge structures predict the same probability distribution. This situation is referred to as ʻempirical indistinguishabilityʼ between two structures and is the main subject of the present paper. Empirical indistinguishability is a stronger form of unidentifiability, which involves not only the parameters, but also the structural and combinatorial properties of the model. In particular, as far as knowledge structures are concerned, a consequence of empirical indistinguishability is that the existence of certain knowledge states cannot be empirically established. Most importantly, it is shown that model identifiability cannot guarantee that a certain knowledge structure is empirically distinguishable from others. The theoretical findings are exemplified in a number of different empirical scenarios.     

Thoughts of Death and Suicide in Early Adolescence

The prevalence and persistence of thoughts of death and suicide during early adolescence were estimated in a community‐based cohort. A latent class approach was used to identify distinct subgroups based on endorsements to depression items administered repeatedly over 24 months. Two classes emerged, with 75% in a low ideation class across four assessments. Less than 2% persisted in the high ideation class over three or more assessments. African American and Asian American adolescents were more likely than European Americans to belong to the high ideation class. No members of the low ideation class endorsed “thought about killing myself,” while “thoughts of death and dying” was endorsed by members of both classes. Implications for interpreting meanings of death and suicide ideation in early adolescence are discussed.     

Simone Weil and the Theo‐Poetics of Compassion

Simone Weil's writings suggest that human compassion is divinely revelatory to the extent that interpersonal union and estrangement intensify identically and simultaneously. The relational space of compassionate communion is aporetic; the more attuned one becomes to an afflicted other, the more unreachable this other is seen to be. In her uniquely poetic style of writing, Weil locates perhaps the most intense experience of God directly in the center of this aporia. Compassion between two people—a sufferer and an empathizer—becomes a locus of divine manifestation as it instantiates the (im)possible distance and oneness of Creation, Incarnation, and Cross.     

Sexual differences in memory in shiny cowbirds

Avian brood parasites depend on other species, the hosts, to raise their offspring. During the breeding season, parasitic cowbirds (Molothrus sp.) search for potential host nests to which they return for laying a few days after first locating them. Parasitic cowbirds have a larger hippocampus/telencephalon volume than non-parasitic species; this volume is larger in the sex involved in nest searching (females) and it is also larger in the breeding than in the non-breeding season. In nature, female shiny cowbirds Molothrus bonariensis search for nests without the male’s assistance. Here we test whether, in association with these neuroanatomical and behavioural differences, shiny cowbirds display sexual differences in a memory task in the laboratory. We used a task consisting of finding food whose location was indicated either by the appearance or the location of a covering disk. Females learnt to retrieve food faster than males when food was associated with appearance cues, but we found no sexual differences when food was associated with a specific location. Our results are consistent with the view that parasitism and its neuroanatomical correlates affect performance in memory tasks, but the effects we found were not in the expected direction, emphasising that the nature of avian hippocampal function and its sexual differences are not yet understood. Received: 30 April 1998 / Accepted after revision: 5 September 1998     

Importance of fathers' parenting to African-American toddler's social and cognitive development

The present study examined the degree to which parenting attitudes and behavior (i.e., self-reported warmth, restrictiveness, and behavioral sensitivity as assessed during a freeplay session) were related to toddlers' development. Results showed a restrictive attitude was negatively related to social and cognitive development, whereas paternal sensitivity was positively related to aspects of social development that are less dependent on language skills (e.g., motor and daily living skills). Fathers of girls exhibited greater sensitivity in their freeplay interactions than fathers of boys. More globally, the present research demonstrates important relations between the parenting attitudes and behavior of low- to working-income African-American fathers and young children's development, and similarities to White, middle-income fathers.     

The Long Arm of Religion: Childhood Adversity,Religion, and Self‐perception Among Black Americans

Significant associations between childhood adversity and adult mental health have been documented in epidemiological and social science research. However, there is a dearth of research examining this relationship among black Americans, as well as into what cultural institutions and practices may help individuals in dealing with childhood adversity. This study suggests that religion may be an important resource for black Americans in the face of early‐life socioeconomic and health disadvantage. Using data from the National Survey of American Life, a nationally representative sample of both African Americans and black Caribbeans (n = 5,191), this study outlines a series of arguments linking childhood adversity, religiosity, and self‐perception among black Americans. The results suggest some support for religious involvement in moderating—or buffering—the harmful effects of childhood adversity on the self‐esteem and mastery among black Americans, specifically religious service attendance and religious coping. In addition, the results reveal that religion may also amplify the deleterious effects of childhood disadvantage on adult mental health. Study limitations are identified and several promising directions for future research are discussed.     

Regression Mixture Models: Does Modeling the Covariance Between Independent Variables and Latent Classes Improve the Results?

Regression mixture models are increasingly used as an exploratory approach to identify heterogeneity in the effects of a predictor on an outcome. In this simulation study, we tested the effects of violating an implicit assumption often made in these models; that is, independent variables in the model are not directly related to latent classes. Results indicate that the major risk of failing to model the relationship between predictor and latent class was an increase in the probability of selecting additional latent classes and biased class proportions. In addition, we tested whether regression mixture models can detect a piecewise relationship between a predictor and outcome. Results suggest that these models are able to detect piecewise relations but only when the relationship between the latent class and the predictor is included in model estimation. We illustrate the implications of making this assumption through a reanalysis of applied data examining heterogeneity in the effects of family resources on academic achievement. We compare previous results (which assumed no relation between independent variables and latent class) to the model where this assumption is lifted. Implications and analytic suggestions for conducting regression mixture based on these findings are noted.