Stronger neural dynamics capture changes in infants' visual working memory capacity over development

Visual working memory (VWM) capacity has been studied extensively in adults, and methodological advances have enabled researchers to probe capacity limits in infancy using a preferential looking paradigm. Evidence suggests that capacity increases rapidly between 6 and 10 months of age. To understand how the VWM system develops, we must understand the relationship between the looking behavior used to study VWM and underlying cognitive processes. We present a dynamic neural field model that captures both real-time and developmental processes underlying performance. Three simulation experiments show how looking is linked to VWM processes during infancy and how developmental changes in performance could arise through increasing neural connectivity. These results provide insight into the sources of capacity limits and VWM development more generally.     

Evaluation of the immediate and subsequent effects of response interruption and redirection on vocal stereotypy

We evaluated 2 3-component multiple-schedule sequences-a response interruption and redirection (RIRD) treatment sequence and a no-interaction control sequence-using a multielement design. With this design, we were able to evaluate the immediate and subsequent effects of RIRD on 2 participants' vocal stereotypy. For both participants, RIRD produced an immediate decrease in vocal stereotypy and did not result in a subsequent increase.     

Feasibility and Preliminary Outcomes of a School-Based Mindfulness Intervention for Urban Youth

Youth in underserved, urban communities are at risk for a range of negative outcomes related to stress, including social-emotional difficulties, behavior problems, and poor academic performance. Mindfulness-based approaches may improve adjustment among chronically stressed and disadvantaged youth by enhancing self-regulatory capacities. This paper reports findings from a pilot randomized controlled trial assessing the feasibility, acceptability, and preliminary outcomes of a school-based mindfulness and yoga intervention. Four urban public schools were randomized to an intervention or wait-list control condition (n = 97 fourth and fifth graders, 60.8% female). It was hypothesized that the 12-week intervention would reduce involuntary stress responses and improve mental health outcomes and social adjustment. Stress responses, depressive symptoms, and peer relations were assessed at baseline and post-intervention. Findings suggest the intervention was attractive to students, teachers, and school administrators and that it had a positive impact on problematic responses to stress including rumination, intrusive thoughts, and emotional arousal.     

Corresponding delay-dependent biases in spatial language and spatial memory

The present study addresses the relationship between linguistic and non-linguistic spatial representations. In three experiments we probe spatial language and spatial memory at the same time points in the task sequence. Experiments 1 and 2 show analogous delay-dependent biases in spatial language and spatial memory. Experiment 3 extends this correspondence, showing that additional perceptual structure along the vertical axis reduces delay-dependent effects in both tasks. These results indicate that linguistic and non-linguistic spatial systems depend on shared underlying representational processes. In addition, we also address how these delay-dependent biases can arise within a single theoretical framework without positing differing prototypes for linguistic and non-linguistic spatial systems.     

Activation of the infralimbic cortex in a fear context enhances extinction learning

Activation of the infralimbic region (IL) of the medial prefrontal cortex (mPFC) reduces conditioned fear in a variety of situations, and the IL is thought to play an important role in the extinction of conditioned fear. Here we report a series of experiments using contextual fear conditioning in which the IL is activated with the GABAa antagonist picrotoxin (Ptx) during a single extinction session in the fear context. We investigate the impact of this manipulation on subsequent extinction sessions in which Ptx is no longer present. First, we demonstrate that a single treatment with intra-IL Ptx administered in a conditioned fear context greatly accelerates the rate of extinction on the following days. Importantly, IL-Ptx also enhances extinction to a different fear context than the one in which IL-Ptx was administered. Thus, IL-Ptx primes extinction learning regardless of the fear context in which the IL was initially activated. Second, activation of the IL must occur in conjunction with a fear context in order to enhance extinction; the extinction enhancing effect is not observable if IL-Ptx is administered in a neutral context. Finally, this extinction enhancing effect is specific to the IL for it does not occur if Ptx is injected into the prelimbic region (PL) of the mPFC. The results indicate a novel persisting control of fear induced by activation of the IL and suggest that IL activation induces changes in extinction-related circuitry that prime extinction learning.     

Feedforward, -backward,and neutral transparency measures for Grade 1 and Grade 2 Greek readers

In the present study, orthographic metrics for Greek children’s Grade 1 and Grade 2 reading materials were presented. Data for five transparency metrics—three of which being neither feedforward nor feedbackward— were presented and offered for use in the research of children’s reading and spelling acquisition. The analysis demonstrated the complex relationships between metrics and compared the results with those obtained for the English language. The structure of these metrics from a variety of corpus sizes was investigated, and we concluded that large corpus sizes do not necessarily make a substantial contribution to the value of such metrics when compared with smaller samples.     

The Effects of Incentives on Visual–Spatial Working Memory in Children with Attention-deficit/Hyperactivity Disorder

Working memory is one of several putative core neurocognitive processes in attention-deficit/hyperactivity disorder (ADHD). The present work seeks to determine whether visual–spatial working memory is sensitive to motivational incentives, a laboratory analogue of behavioral treatment. Participants were 21 children (ages 7–10) with a diagnosis of ADHD-combined type. Participants completed a computerized spatial span task designed to assess storage of visual–spatial information (forward span) and manipulation of the stored information (backward span). The spatial span task was completed twice on the same day, once with a performance-based incentive (trial-wise feedback and points redeemable for prizes) and once without incentives. Participants performed significantly better on the backward span when rewarded for correct responses, compared to the no incentive condition. However, incentives had no effect on performance during the forward span. These findings may suggest the use of motivational incentives improved manipulation, but not storage, of visual–spatial information among children with ADHD. Possible explanations for the differential incentive effects are discussed, including the possibility that incentives prevented a vigilance decrement as task difficulty and time on task increased.     

The temporal representation of in-phase and anti-phase movements

We have proposed that the stability of bimanual coordination is influenced by the complexity of the representation of the task goals. Here, we present two experiments to explore this hypothesis. First, we examined whether a temporal event structure is present in continuous movements by having participants vocalize while producing bimanual circling movements. Participants tended to vocalize once per movement cycle when moving in-phase. In contrast, vocalizations were not synchronized with anti-phase movements. While the in-phase result is unexpected, the latter would suggest anti-phase continuous movements lack an event structure. Second, we examined the event structure of movements marked by salient turn-around points. Participants made bimanual wrist flexion movements and were instructed to move 'in synchrony' with a metronome, without specifying how they should couple the movements to the metronome. During in-phase movements, participants synchronized one hand cycle with every metronome beat; during anti-phase movements, participants synchronized flexion of one hand with one metronome beat and extension of the other hand with the next beat. The results are consistent with the hypothesis that the instability of anti-phase movements is related to their more complex (or absent) event representation relative to that associated with in-phase movements.     

Feedforward, -backward, and neutral transparency measures for British English

Orthographic transparency metrics for opaque or deep languages, such as French and English, have tended to focus on feedforward and/or feedback directions, with claims made for the influence of both on reading. In the present study, data for five transparency metrics for southern British English, three of which are neither feedforward nor feedback, are presented, demonstrating the complex relationships between the metrics and offering an explanation for feedback effects in children’s reading accuracy. The structure of such metrics from a variety of corpus sizes and origins is investigated, and it is concluded that large corpus sizes do not make a substantial contribution to the value of such metrics, when compared with smaller samples, and that adult and child corpuses have very similar profiles. Probabilities of occurrence for the phonemes, graphemes, and sonographs in this study may be downloaded from brm.psychonomic-journals.org/content/supplemental.