Relational reasoning is an essential component of fluid intelligence, and is known to have a protracted developmental trajectory. To date, little is known about the neural changes that underlie improvements in reasoning ability over development. In this event-related functional magnetic resonance imaging (fMRI) study, children aged 8-12 and adults aged 18-25 performed a relational reasoning task adapted from Raven’s Progressive Matrices. The task included three levels of relational reasoning demands: REL-0, REL-1, and REL-2. Children exhibited disproportionately lower accuracy than adults on trials that required integration of two relations (REL-2). Like adults, children engaged lateral prefrontal cortex (PFC) and parietal cortex during task performance; however, they exhibited different timecourses and activation profiles, providing insight into their approach to the problems. As in prior studies, adults exhibited increased rostrolateral PFC (RLPFC) activation when relational integration was required (REL-2 > REL-1, REL-0). Children also engaged RLPFC most strongly for REL-2 problems at early stages of processing, but this differential activation relative to REL-1 trials was not sustained throughout the trial. These results suggest that the children recruited RLPFC while processing relations, but failed to use it to integrate across two relations. Relational integration is critical for solving a variety of problems, and for appreciating analogies; the current findings suggest that developmental improvements in this function rely on changes in the profile of engagement of RLPFC, as well as dorsolateral PFC and parietal cortex.

During development, children improve at retrieving and using rules to guide their behavior and at flexibly switching between these rules. In this study, we used functional magnetic resonance imaging to examine the changes in brain function associated with developmental changes in flexible rule use. Three age groups (8 -12, 13-17, and 18 -25 years) performed a task in which they were cued to respond to target stimuli on the basis of simple task rules. Bivalent target stimuli were associated with different responses, depending on the rule, whereas univalent target stimuli were associated with fixed responses. The comparison of bivalent and univalent trials enabled the identification of regions modulated by demands on rule representation. The comparison of rule-switch and rule-repetition trials enabled the identification of regions involved in rule switching. We have used this task previously in adults and have shown that ventrolateral prefrontal cortex (VLPFC) and the (pre)-supplementary motor area (pre-SMA/SMA) have dissociable roles in task-switching, such that VLPFC is associated most closely with rule representation, and pre-SMA/SMA is associated with suppression of the previous task set (Crone et al., 2006a). Based on behavioral data in children (Crone et al., 2004), we had predicted that regions associated with task-set suppression would show mature patterns of activation earlier in development than regions associated with rule representation. Indeed, we found an adult-like pattern of activation in pre-SMA/SMA by adolescence, whereas the pattern of VLPFC activation differed among children, adolescents, and adults. These findings suggest that two components of task-switching-rule retrieval and task-set suppression-follow distinct neurodevelopmental trajectories.

Psychological interventions targeting wellbeing can reliably increase wellbeing and decrease depressive symptoms. However, only a handful of studies have implemented wellbeing interventions online, and those studies have largely done so in a way that prioritizes experimental control over realism and scalability. We sought to take existing wellbeing interventions with established efficacy and to evaluate their impact when translated into a format that is publicly accessible, scalable, and designed with the goal of engaging users. Participants in this fully online trial were first-time registrants of the Happify platform, a fully automated web and mobile wellbeing intervention grounded in positive psychology, cognitivebehavioral therapy, and mindfulness-based stress reduction, which has offered wellbeing programs to over 3 million registrants to date. Consenting participants were randomly assigned to access the full Happify platform or a psychoeducation comparison condition and further categorized by their usage during the study: recommended usage (a minimum of 2-3 activities per week) or low usage (usage less than the recommended level). Participants were assessed on depressive symptoms, anxiety symptoms, and a composite measure of resilience at baseline and 8 weeks later. Participants who used Happify at the recommended level reported fewer depressive and anxiety symptoms and greater resilience after 8 weeks than participants who used Happify at a low level or participants who used the psychoeducation condition at any level. The Happify group also experienced greater rates of reduction in depression and anxiety symptom severity category, and had a greater net benefit (% users who improved minus % users who deteriorated), compared to the other groups. The results of this study suggest a successful first attempt at implementing and scaling a comprehensive package of lab-tested wellbeing interventions without losing efficacy.

The present study examines 5- to 8-year-old children's relation reasoning in solving matrix completion tasks. This study incorporates a componential analysis, an eye-tracking method, and a microgenetic approach, which together allow an investigation of the cognitive processing strategies involved in the development and learning of children's relational thinking. Developmental differences in problem-solving performance were largely due to deficiencies in engaging the processing strategies that are hypothesized to facilitate problem-solving performance. Feedback designed to highlight the relations between objects within the matrix improved 5- and 6-year-olds' problem-solving performance, as well as their use of appropriate processing strategies. Furthermore, children who engaged the processing strategies early on in the task were more likely to solve subsequent problems in later phases. These findings suggest that encoding relations, integrating rules, completing the model, and generalizing strategies across tasks are critical processing components that underlie relational thinking. (PsycINFO Database Record