Effect sizes in ANCOVA and difference-in-differences designs

It is common practice in both randomized and quasi-experiments to adjust for baseline characteristics when estimating the average effect of an intervention. The inclusion of a pre-test, for example, can reduce both the standard error of this estimate and—in non-randomized designs—its bias. At the same time, it is also standard to report the effect of an intervention in standardized effect size units, thereby making it comparable to other interventions and studies. Curiously, the estimation of this effect size, including covariate adjustment, has received little attention. In this article, we provide a framework for defining effect sizes in designs with a pre-test (e.g., difference-in-differences and analysis of covariance) and propose estimators of those effect sizes. The estimators and approximations to their sampling distributions are evaluated using a simulation study and then demonstrated using an example from published data.     

Task difficulty modulates brain-behavior correlations in language production and cognitive control: Behavioral and fMRI evidence from a phonological go/no-go picture-naming paradigm

Language production and cognitive control are complex processes that involve distinct yet interacting brain networks. However, the extent to which these processes interact and their neural bases have not been thoroughly examined. Here, we investigated the neural and behavioral bases of language production and cognitive control via a phonological go/no-go picture-naming task. Naming difficulty and cognitive control demands (i.e., conflict monitoring and response inhibition) were manipulated by varying the proportion of naming trials (go trials) and inhibition trials (no-go trials) across task runs. The results demonstrated that as task demands increased, participants’ behavioral performance declined (i.e., longer reaction times on naming trials, more commission errors on inhibition trials) whereas brain activation generally increased. Increased activation was found not only within the language network but also in domain-general control regions. Additionally, right superior and inferior frontal and left supramarginal gyri were sensitive to increased task difficulty during both language production and response inhibition. We also found both positive and negative brain–behavior correlations. Most notably, increased activation in sensorimotor regions, such as precentral and postcentral gyri, was associated with better behavioral performance, in both successful picture naming and successful inhibition. Moreover, comparing the strength of correlations across conditions indicated that the brain–behavior correlations in sensorimotor regions that were associated with improved performance became stronger as task demands increased. Overall, our results suggest that cognitive control demands affect language production, and that successfully coping with increases in task difficulty relies on both language-specific and domain-general cognitive control regions.     

The effects of perpetrator age and abuse disclosure on the relationship between feelings provoked by child sexual abuse and posttraumatic stress

The present study examined the relationship between feelings provoked by child sexual abuse (CSA) and posttraumatic stress disorder (PTSD) symptom scores in a sample of 163 female survivors of CSA. Finkelhor and Browne's traumagenic dynamics model was applied. The interactive effects of provoked feelings with perpetrator age and the existence of abuse disclosure were also studied. Results showed an overall relationship between feelings provoked by CSA and PTSD symptom scores. Feelings of stigma, betrayal, and powerlessness as a result of CSA were associated with PTSD symptom score when the entire group of CSA victims was analyzed. The role of traumatic sexualization was relevant only when analyzed in interaction with the age of the perpetrator and disclosure. The relationship between traumatic sexualization and PTSD symptom scores was only significant when the abuse was committed by an adult perpetrator and when a disclosure was made during the time of abuse, or a short time after the abuse had occurred.     

Lunch Buddy Mentoring for Children Victimized by Peers: Two Pilot Studies

The authors describe two pilot studies examining the potential benefits of Lunch Buddy (LB) mentoring, a manualized approach to school-based mentoring. LB mentoring takes place during the school lunch period and is designed to promote positive changes in children's peer relationships. In both studies, changes in peer victimization were assessed after one and three semesters of LB mentoring. In the first study, LB mentors were paired with elementary school children (N = 24) identified by child and teacher reports as victimized by peers. Results revealed significant declines in self- and teacher-rated victimization after one and three semesters of mentoring. In the second study, LB mentors were paired with victimized children who also engaged in bullying behavior (N = 23). Results indicated significant declines in self- and teacher-ratings of peer victimization after three semesters of mentoring. In both studies, ratings of perceived harm were low and ratings of satisfaction were high. Discussed are the implications of these findings for future research and for efforts to develop a nonharmful way to help children who are repeatedly victimized.     

AMPA/kainate, NMDA, and dopamine D1 receptor function in the nucleus accumbens core: a context-limited role in the encoding and consolidation of instrumental memory

Neural integration of glutamate- and dopamine-coded signals within the nucleus accumbens (NAc) is a fundamental process governing cellular plasticity underlying reward-related learning. Intra-NAc core blockade of NMDA or D1 receptors in rats impairs instrumental learning (lever-pressing for sugar pellets), but it is not known during which phase of learning (acquisition or consolidation) these receptors are recruited, nor is it known what role AMPA/kainate receptors have in these processes. Here we show that pre-trial intra-NAc core administration of the NMDA, AMPA/KA, and D1 receptor antagonists AP-5 (1 microg/0.5 microL), LY293558 (0.01 or 0.1 microg/0.5 microL), and SCH23390 (1 microg/0.5 microL), respectively, impaired acquisition of a lever-pressing response, whereas post-trial administration left memory consolidation unaffected. An analysis of the microstructure of behavior while rats were under the influence of these drugs revealed that glutamatergic and dopaminergic signals contribute differentially to critical aspects of the initial, randomly emitted behaviors that enable reinforcement learning. Thus, glutamate and dopamine receptors are activated in a time-limited fashion-only being required while the animals are actively engaged in the learning context.     

Intentional Teaching Facilitates Young Children's Comprehension and Use of a Symbolic Object

Children are exposed to symbolic objects that they have to learn to use very early in life. The authors’ aim was to examine whether it is possible to intentionally teach young children the symbolic function of an object. They employed a search task in which children had to use a map to find a toy. Experiment 1 revealed that with no instruction 3-year-, 10-month-old children were quite successful; 3-year-, 6-month-olds showed a divided performance; and 3-year-, 0-month-olds failed. With this baseline, Experiment 2 compared the performance of 3-year-, 0-month-olds in three different conditions: no-instruction, complete instruction (before the task begins), and teaching (complete instruction plus corrective feedback); only children in the teaching condition succeeded. However, children 6 months younger, 2-year-, 6-month-olds, failed despite teaching that was provided (Study 3). This research shows that at some points in development instruction is not enough; intentional teaching in communicative contexts is the mechanism that boosts symbolic understanding in early childhood.     

The emotional impact of bullying and cyberbullying on victims: a European cross-national study

Past research has demonstrated the effects of bullying can be severe and long term for the individuals involved. The main aim of this study is to analyze the emotional impact on victims of traditional bullying, both direct and indirect forms, and of cyberbullying through mobile phones and the Internet. A sample of 5,862 adolescents from three different countries, Italy (N = 1,964), Spain (N = 1,671), and England (N = 2,227), responded to a questionnaire that asked if they had experience of various forms of bullying, and the consequent emotional impact. The results show that both traditional bullying and cyberbullying have a significant prevalence in the samples. Emotional responses are linked to types of bullying. Analysis of answers identified specific emotional profiles for the different types of bullying and cyberbullying. Direct bullying and cyberbullying via mobile phone showed similar profiles, and also indirect bullying and cyberbullying using the Internet. Similarities and differences between profiles are discussed and some hypotheses are presented to explain the results. In addition, school grade, gender, country, and severity of bullying episodes were related to the specific emotional profiles of each type of bullying. Aggr. Behav. 38:342‐356, 2012. © 2012 Wiley Periodicals, Inc.