The Use of Propensity Scores in Mediation Analysis

Mediation analysis uses measures of hypothesized mediating variables to test theory for how a treatment achieves effects on outcomes and to improve subsequent treatments by identifying the most efficient treatment components. Most current mediation analysis methods rely on untested distributional and functional form assumptions for valid conclusions, especially regarding the relation between the mediator and outcome variables. Propensity score methods offer an alternative whereby the propensity score is used to compare individuals in the treatment and control groups who would have had the same value of the mediator had they been assigned to the same treatment condition. This article describes the use of propensity score weighting for mediation with a focus on explicating the underlying assumptions. Propensity scores have the potential to offer an alternative estimation procedure for mediation analysis with alternative assumptions from those of standard mediation analysis. The methods are illustrated investigating the mediational effects of an intervention to improve sense of mastery to reduce depression using data from the Job Search Intervention Study (JOBS II). We find significant treatment effects for those individuals who would have improved sense of mastery when in the treatment condition but no effects for those who would not have improved sense of mastery under treatment.     

Associations between symptoms of maternal postpartum depression,gestational age and infant social withdrawal: A longitudinal study in a community cohort

Infant social withdrawal is a risk factor for non-optimal child development; thus, it is important to identify risk factors associated with withdrawal. In a large community sample (N = 19,017), we investigate whether symptoms of maternal and partner postpartum depression (PPD; measured with the Edinburgh Postnatal Depression Scale) and prematurity are predictors of infant social withdrawal (measured with the Alarm Distress Baby Scale). Withdrawal was assessed at 2–3, 4–7 and 8–12 months postpartum. Linear regressions showed that prematurity predicted higher infant social withdrawal at all time points, and maternal symptoms of PPD were positively associated with withdrawal at 2–3 months. Logistic regressions showed that odds for elevated social withdrawal were increased with elevated levels of maternal symptoms of PPD at 2–3 and 8–12 months. Partner's symptoms of PPD were not associated with withdrawal. Future studies should investigate how PPD symptoms and prematurity may impact the individual development of social withdrawal.     

A Neuropsychological Model of Mentally Tough Behavior

Four studies were conducted with two primary objectives: (a) to conceptualize and measure mental toughness from a behavioral perspective and (b) to apply relevant personality theory to the examination of between‐person differences in mentally tough behavior. Studies 1 (N = 305 participants from a range of different sports) and 2 (N = 110 high‐level cricketers) focused on the development of an informant‐rated mental toughness questionnaire that assessed individual differences in ability to maintain or enhance performance under pressure from a wide range of stressors. Studies 3 (N = 214) and 4 (N = 196) examined the relationship between reinforcement sensitivities and mentally tough behavior in high‐level cricketers. The highest levels of mental toughness reported by coaches occurred when cricketers were sensitive to punishment and insensitive to reward. Study 4 suggested that such players are predisposed to identify threatening stimuli early, which gives them the best possible opportunity to prepare an effective response to the pressurized environments they encounter. The findings show that high‐level cricketers who are punishment sensitive, but not reward sensitive, detect threat early and can maintain goal‐directed behavior under pressure from a range of different stressors.     

Associations Between Maternal Mental Health and Child Emotional and Behavioral Problems: Does Prenatal Mental Health Matter?

This study examined associations between elevated symptoms of prenatal depression or anxiety and offspring emotional and behavioral problems during mid to late childhood taking into account the impact of later maternal mental health symptoms. The sample consisted of 2,891 women and their children (49 % male) from a prospective, community-based study, the Avon Longitudinal Study of Parents and Children. Women completed measures of depressive (Edinburgh Postnatal Depression Scale) and anxious (Crown Crisp Experiential Index) symptoms at regular intervals beginning in pregnancy. Mothers and teachers assessed offspring emotional and behavioral problems using the Strengths and Difficulties Questionnaire when children were 10–11 years old. Multivariable regression models were fit to address study hypotheses. Exposure to elevated symptoms of maternal depression during pregnancy was associated with increased total offspring emotional and behavioral problems, even after controlling for later maternal mental health problems and a range of sociodemographic and psychosocial characteristics, according to mothers’ but not teachers’ reports. Similarly, children exposed to elevated symptoms of maternal anxiety during pregnancy were reported to have increased total emotional and behavioral problems by mothers but not by teachers. We found support for modest associations between elevated symptoms of maternal depression and anxiety during the prenatal period and certain domains of offspring emotional and behavioral problems in mid to late childhood above and beyond the impact of later maternal mental health problems. These findings highlight the need for additional clinical and research attention to the prenatal period and to both maternal depression and anxiety.     

The Positive Influence of Creating a Holistic Facial Composite on Video Line‐up Identification

Witnesses to a crime may be asked to create a facial composite of the offender from memory. They may then view a suspect in a police line‐up. Previous research on this topic has found both recognition impairment and enhancement following composite construction. In Experiment 1, creator‐participants employed the holistic facial composite system system EFIT‐V or the feature‐based E‐FIT system to create a single composite, and in Experiment 2, creators constructed up to three EFIT‐Vs. In both experiments, facial composite creators were one‐and‐a‐half times more likely than non‐composite creating controls to make correct target identifications from a video line‐up. No between condition effects were found in target‐absent trials in Experiment 1. The development of holistic facial composite systems has enhanced suspect identification rates in police investigations, and these results suggest that the use of such a system can also have a positive influence on a composite‐creating witness' later recognition of the suspect. Copyright © 2014 John Wiley & Sons, Ltd.     

The dimensions of deception detection: Self‐reported deception cue use is underpinned by two broad factors

Many perceived cues to deception have been reported in the literature, but little attention has been paid to how they are combined when making deception judgments. The present research used a data‐driven approach to investigate how cues are integrated when evaluating veracity. Two hundred fifteen participants performed a deception detection task before completing a deception cue use questionnaire. A factor analysis of the questionnaire data produced two dimensions, one associated with nonverbal cues to anxiety and the other associated with detail and level of involvement. The present work extends our understanding of deception detection processes and underlines the importance of examining not only the cues that people use but also the way in which they use them.     

Whatever happened to Kony2012? Understanding a global Internet phenomenon as an emergent social identity

Kony2012 was a viral Internet video that attracted unprecedented online interest in promoting a campaign to arrest the leader of an African militant group. The current research considers the social psychological bases of social media‐based collective action. In three cross‐sectional surveys (N = 304) collected before, on, and after the key action date of 20 April 2012, we consider the nature (opinion based or global) and function (emergent or transforming) of social identity in modern forms of social action. Multigroup structural equation modelling showed that Kony2012 action was best captured by an emergent opinion‐based social identity. Moreover, the same factors that predicted Kony2012 action generally also predicted engagement in new repertoires of protest (involving the use of social media) and an observable traditional socio‐political action (signing a letter to a government minister). The results suggest that there is no sharp dividing line between traditional and new forms of collective action and that both may be understood as valid expressions of collective selfhood. Copyright © 2015 John Wiley & Sons, Ltd.     

Prenatal, perinatal and neonatal stimulation: a survey of neonatal nurseries

A recent survey was conducted on stimulation of mothers and babies during pregnancy and the neonatal period. The survey was responded to by 82 neonatology staff members from Neonatal Intensive Care Units (NICUs) at hospitals in the United States. Some forms of stimulation were extremely common including (1) skin-to-skin following birth in the delivery room (83% of hospitals); (2) containment (swaddling and surrounded by blanket rolls) in the NICU (86%); (3) music in the NICU (72%); (4) rocking in the NICU (85%); (5) kangaroo care (98%); (6) non-nutritive sucking during tubefeedings in the NICU (96%); and (7) breastfeeding in the NICU (100%). Other forms of stimulation occurred less frequently including (1) pregnancy massage (19%); (2) labor massage (30%); (3) the Doula (assistant who comforts during labor and delivery) (30%); (4) waterbeds in the NICU (23%); and (5) preterm infant massage in the NICU (38%).