Infant Pathways to Externalizing Behavior: Evidence of Genotype × Environment Interaction

To further the understanding of the effects of early experiences, 9-month-old infants were observed during a frustration task. The analytical sample was composed of 348 linked triads of participants (adoptive parents, adopted child, and birth parent[s]) from a prospective adoption study. It was hypothesized that genetic risk for externalizing problems and affect dysregulation in the adoptive parents would independently and interactively predict a known precursor to externalizing problems: heightened infant attention to frustrating events. Results supported the moderation hypotheses involving adoptive mother affect dysregulation: Infants at genetic risk showed heightened attention to frustrating events only when the adoptive mother had higher levels of anxious and depressive symptoms. The Genotype × Environment interaction pattern held when substance use during pregnancy was considered.     

Multilevel Mediation With Small Samples: A Cautionary Note on the Multilevel Structural Equation Modeling Framework

Multilevel structural equation modeling (ML-SEM) for multilevel mediation is noted for its flexibility over a system of multilevel models (MLMs). Sample size requirements are an overlooked limitation of ML-SEM (100 clusters is recommended). We find that 89% of ML-SEM studies have fewer than 100 clusters and the median number is 44. Furthermore, 75% of ML-SEM studies implement 2–1–1 or 1–1–1 models, which can be equivalently fit with MLMs. MLMs theoretically have lower sample size requirements, although studies have yet to assess small sample performance for multilevel mediation. We conduct a simulation to address this pervasive problem. We find that MLMs have more desirable small sample performance and can be trustworthy with 10 clusters. Importantly, many studies lack the sample size and model complexity to necessitate ML-SEM. Although ML-SEM is undeniably more flexible and uniquely positioned for difficult problems, small samples often can be more effectively and simply addressed with MLMs.     

A linguistic dissociation in Williams syndrome: Good at gender agreement but poor at lexical retrieval

Williams syndrome (WS) is a rareneuro-developmental disorder characterised byspared language in the face of serious deficitsin nonlinguistic cognitive abilities. Weconducted a study on ten WS individuals inwhich gender agreement and gender assignmentwere assessed by means of two tasks: gendercategorisation and gender concord. Subjectsperformed gender categorisation to real nounswhose gender was regular or exceptional giventheir ending, and to invented nouns which werecomposed of nonword or word stems and realword-endings. The same material was used in thegender concord task in which subjects had tomatch the items with the appropriate form ofthe article and the adjective carrying genderagreement. In the gender categorisation of realwords, WS were lower than controls but bothgroups demonstrated a similar sensitivity togender-ending regularities. In the gendercategorisation of nonwords, the results showeda clear dissociation. The WS subjects producedmore ending-consistent responses than thecontrols. Contrary to the controls, WS reliedheavily on the gender clue provided by theending even when the gender of the word evokedby the stem of the invented word was opposed tothat evoked by the ending. Participants with WSwere not influenced by the specific word evokedby the stem of the invented word. In the secondtask (concord task), the WS subjects performed well although lower than thecontrols. We concluded that the WS people werenot impaired in gender agreement which relieson syntactic rules and/or on the extraction ofregularities but experienced difficulties inretrieving lexical instances.     

Peripheral Narrowing among Experienced and Inexperienced Rifle Shooters under Low- and High-Stress Conditions

Abstract

This study examined Easterbrook's (1959) hypothesis that performance on a primary task would improve or at least be maintained with increased levels of arousal, while performance on a secondary task would decrease. To test this hypothesis, the performance of 20 collegiate rifle shooters (10 experienced, 10 inexperienced) on a primary target shooting task and a secondary auditory task were compared while shooting under low- and high-time stress conditions. Heart rate results, but not a self-report anxiety measure, provided evidence for the effectiveness of the stress manipulation. The results primarily supported Easterbrook's hypothesis. There were no differences in secondary task performance between experienced and inexperienced shooters. However, subjects who first underwent high time stress followed by low (H-L) shot better than those given the reverse order (L-H). These findings are discussed in relation to the attention demands of self-paced sports as well as the transfer effects of stress.     

Velocity profiling using inertial sensors for freestyle swimming

The ability to unobtrusively measure velocity in the aquatic environment is a fundamental challenge for engineers and sports scientists and important in assessing the skill level. The aim of this research was to develop a method for velocity profiling in freestyle swimming utilising a purpose-built inertial sensor. Seventeen swimmers with different experience levels participated in this study performing a total of 159 laps in the velocity range from 0.79 to 2.04 m s^?1. Data were collected using a triaxial accelerometer and a tethered velocity meter. The collected acceleration data were filtered using a 0.5 Hz Hamming-windowed FIR filter to remove the gravitational acceleration before the lap velocity profiles were calculated. These calculated lap velocity profiles were then compared with the velocity profiles measured by the velocity meter using Bland–Altman analysis. The scattering follows a normal distribution with a mean skewness of 0.96 ± 0.47 and kurtosis of 2.93 ± 1.12. The results show that an inertial sensor alone can be used to determine a lap velocity profile from single point acceleration records.     

Collaborative feedback and reflection for professional growth: preparing first-year pre-service teachers for participation in the community of practice

Teaching has been described as an emerging community of practice. Within such professional communities, the processes of reflection and collaborative dialogue, or critical transformative dialogue, are central to the maintenance and improvement of professional practice for individuals, and the field. This paper reports on the challenges experienced by a group of first-year pre-service teachers engaging in a process of reflection and critique with peers, as they participated in a program focused on the development of core practices of teaching. These pre-service teachers' responses indicated their growing understanding of the importance of engaging in ongoing critical dialogue, as part of the “unnatural” aspects of teaching. The paper concludes with a reflection on the value of feedback from the earliest stages of professional learning.     

Maintenance of responding when reinforcement becomes delayed

In four experiments with rats, we examined the persistence of behavior when reinforcement was switched from immediate to delayed. In Experiment 1, lever pressing elicited by instrumental training with immediate reinforcement continued when a 20-sec delay of reinforcement was introduced (easy-to-hard condition), whereas when the delay condition was introduced from the start (hard-to-hard condition), responding remained low throughout. A similar result was obtained in Experiment 2, in which lever pressing was elicited by a classical conditioning (autoshaping) procedure. In Experiment 3, rats initially trained with delayed reinforcement continued to respond at a low rate when switched to immediate reinforcement (hard-to-easy condition). By measuring magazine entry (goal tracking) as well as lever pressing (sign tracking) in Experiment 4, we confirmed that such transfer effects at least partly involve the persistence of whatever type of behavior was initially dominant.     

Do more hours in center-based care cause more externalizing problems? A cross-national replication study

Whether high quantities of center-based care cause behavior problems is a controversial question. Studies using covariate adjustment for selection factors have detected relations between center care and behavior problems, but studies with stronger internal validity less often find such evidence. We examined whether within-child changes in hours in center-based care predicted changes in externalizing problems in toddlers and preschoolers (N = 10,105; 49% female; data collection 1993–2012) in seven studies, including from Germany, Netherlands, Norway, two from Canada and two from the U.S. Race/ethnicity data were only collected in the United States (57% and 80% White; 42% and 13% African-American; 1.2% and 5% Latinx). Meta-analyses showed no association (r = .00, p = .88) between hours in center-based care and externalizing problems.