Propensity score estimation with boosted regression for evaluating causal effects in observational studies

Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate estimation of propensity scores is impeded by large numbers of covariates, uncertain functional forms for their associations with treatment selection, and other problems. This article demonstrates that boosting, a modern statistical technique, can overcome many of these obstacles. The authors illustrate this approach with a study of adolescent probationers in substance abuse treatment programs. Propensity score weights estimated using boosting eliminate most pretreatment group differences and substantially alter the apparent relative effects of adolescent substance abuse treatment.     

Faith in community and communities of faith? government rhetoric and religious identity in Urban Britain

This paper examines the concept of community and the discourse around it in the context of the religious diversity in urban areas in England. Sociology has a long history of working with, deconstructing, and at times rejecting the usefulness of the term ‘community’ and many scholars have in the context of postmodernity preferred to talk about processes of identity formation and networking. Constructions of identity in which faith affiliation plays a salient role are probably becoming more common and more politically significant. However, an integrated theory of the relationship between religion, community, ethnicity, and identity remains to be developed and this paper attempts some tentative first steps.

In their search for ‘feel good’ terminology, politicians in democracies such as the UK have often turned to the language of community and continue to do so. Faced with the task of managing local conflicts and delivering services which are responsive to the demands of users, contemporary governments have increasingly adopted communitarian positions and the language of social capital. In recent years in the UK, religion has moved up the political agenda and an official discourse and policy initiatives structured around the notion of ‘faith communities’ have emerged.

The New Labour government has indeed put its faith in community and sought to co‐opt communities of faith into its ‘project’. However, it is far from clear that there is a coherent understanding of the notion of faith community or of the two words that make up the phrase. One may question whether the government discourse resonates with the understandings of community and identity in the major faith traditions found in the contemporary city. An examination of some of the official discourse set alongside the changing and conflicting identities of some ‘faith communities’ in London and other British cities suggests that the British State's current simplistic approach to engaging with religious diversity is an inadequate basis for policy development.     

Assessment of deviant arousal in adult male sex offenders with developmental disabilities

Ten individuals, residing in a treatment facility specializing in the rehabilitation of sex offenders with developmental disabilities, participated in an arousal assessment involving the use of the penile plethysmograph. The arousal assessments involved measuring change in penile circumference to various categories of stimuli both appropriate (adult men and women) and inappropriate (e.g., 8- to 9-year-old boys and girls). This approach extends the existing assessment literature by the use of repeated measurement and single-subject experimental design. Data from these assessments were analyzed to determine if clear and informative outcomes were obtained. Overall, three general patterns of results emerged. Some participants showed differentiated deviant arousal or higher levels of arousal to specific inappropriate stimuli (deviant is a term used in the existing sex-offender literature to describe this type of arousal). Other participants showed undifferentiated deviant arousal, in which case they showed nonspecific arousal to inappropriate stimuli. The remaining participants showed no arousal to inappropriate stimuli but did show arousal to appropriate stimuli. Implications for assessment, treatment, and future directions are discussed.     

Left posterior auditory-related cortices participate both in speech perception and speech production: Neural overlap revealed by fMRI

Recent neuroimaging studies and neuropsychological data suggest that there are regions in posterior auditory cortex that participate both in speech perception and speech production. An outstanding question is whether the same neural regions support both perception and production or whether there exist discrete cortical fields subserving these functions. Previous neurophysiological studies suggest that there is indeed regional overlap between these systems, but those studies used a rehearsal task to assess production. The present study addressed this question in an event-related fMRI experiment in which subjects listened to speech and in separate trials, performed a covert object naming task. Single subject analysis revealed regions of coactivation for speech perception and production in the left posterior superior temporal sulcus (pSTS), left area Spt (a region in the Sylvian fissure at the parietal-temporal boundary), and left inferior frontal gyrus. These results are consistent with lesion data and previous physiological data indicating that posterior auditory cortex plays a role in both reception and expression of speech. We discuss these findings within the context of a neuroanatomical framework that proposes these neural sites are a part of an auditory-motor integration system.     

Attending to affect: appraisal strategies modulate the electrocortical response to arousing pictures

Arousing (unpleasant and pleasant) pictures elicit increased neurophysiological measures of perceptual processing. In particular, the electrocortical late positive potential (LPP) is enhanced for arousing, compared with neutral, pictures. To determine whether the magnitude of the LPP is sensitive to the way stimuli are appraised, 16 participants viewed both pleasant and unpleasant pictures and categorized them along an affective or nonaffective dimension. Results indicate that the LPP was reduced for both pleasant and unpleasant pictures when participants made nonaffective, compared with affective, judgments. These results are consistent with previous studies that have used functional neuroimaging to investigate the role of appraisal on emotional processing. The results are further discussed in terms of the utility of using the LPP to study emotion regulation.     

Reappraisal modulates the electrocortical response to unpleasant pictures

Cognitive strategies such as reappraisal reduce the intensity of negative experience and brain activity that is sensitive to emotional salience. The time course of reappraisal-related neural modulation remains unclear, and it is unknown whether the electrocortical response to emotional stimuli is sensitive to reappraisal. Event-related brain potentials were recorded first while participants passively viewed pleasant, unpleasant, and neutral pictures, and then during an emotion regulation block in which participants were instructed to attend to or reappraise unpleasant pictures. The late positive potential (LPP) was enhanced for pleasant and unpleasant pictures in the passive viewing block, and reappraisal resulted in a reliably reduced LPP—a protracted modulation that began 200 msec after stimulus onset. The degree of LPP modulation was positively related to reductions in the self-reported emotional intensity that followed emotion regulation instructions. These results indicate that reappraisal modulates early electrocortical activity that is related to emotional salience, and that the LPP is a useful tool for studying emotion regulation.     

Child well-being in an era of welfare reform: the sensitivity of transitions in development to policy change

This study examined the age-specific pattern of effects of welfare policies on child achievement. Drawing from 7 random-assignment welfare and antipoverty evaluations that provided more than 30,000 observations of children's achievement, this study found that times of developmental transition are the only periods sensitive to the changes in families brought about by these policies. More specifically, small positive effects of welfare and antipoverty policies were found for children making the transition into middle childhood, and small negative effects of these same policies were found for children making the transition out of middle childhood and into early adolescence. Effects were robust across various program groupings and could not be attributed to family characteristics that differ for children of different ages. This research informs the understanding of how changes in employment and income for low-income parents affect development across childhood.     

Familiarization, attention, and recognition memory in infancy: an event-related potential and cortical source localization study

This study investigated the effects of familiarization and attention on event-related potential (ERP) correlates of recognition memory in infants. Infants 4.5, 6, or 7.5 months of age were either familiarized with 2 stimuli that were used during later testing or presented 2 stimuli that were not used later. Then, infants were presented with a recording of Sesame Street to elicit attention or inattention and presented with familiar and novel stimuli. A negative ERP component over the frontal and central electrodes (Nc) was larger in the preexposure familiarization group for novel- than for familiar-stimulus presentations, whereas the Nc did not differ for the group not receiving a familiarization exposure. Spatial independent components analysis of the electroencephelogram and "equivalent current dipole" analysis were used to examine putative cortical sources of the ERP components. The cortical source of Nc was located in areas of prefrontal cortex and anterior cingulate cortex.     

What is enumerated by subitization mechanisms?

Subitization, the rapid enumeration of small numbers of objects, is often held to reflect a general ability to process three or four items simultaneously. However, questions as to which types of visual representations count as items for subitization have, thus far, received relatively little attention. In several new experiments, we instructed participants to enumerate three or four colored regions in a display. In some trials, all of these regions belonged to separate visual objects, whereas in others, two or more belonged to the same object(s). We found far slower enumeration in the latter case than in the former case, a result that cannot be attributed to Stroop interference from the number of attended objects in a display. We conclude that subitization mechanisms cannot operate on small fragments of shape and color alone, even when such fragments are easily individuated from one another. Rather, such mechanisms are compelled to operate on object representations.