publications

2024

1. Estimating the Replicability of Psychology Experiments After an Initial Failure to Replicate

   Veronica Boyce, Ben Prystawski, Adani B. Abutto, and 17 more authors

   Collabra: Psychology, Nov 2024

   Abs

   When a replication fails, scientists have to decide whether to make a second attempt or move on. Psychology researchers who attempt to replicate studies often face this decision, given the empirical rate of replication success in psychology, which is lower than desired. Here, we report 17 re-replications of experiments for which an original replication had failed. In 5/17 of these “rescue” projects (29%), the “rescue” study mostly or fully replicated the original results, albeit with a smaller effect size; in the other 12, the second replication was also judged to have failed. We speculate that successful rescue projects were due to larger sample sizes or methodological changes such as attention checks. In the absence of obvious weaknesses in a failed replication study’s sample or procedure, however, it may be most efficient to stop pursuing an effect after a single failed replication.

2021

1. Prefrontal and frontostriatal structures mediate academic outcomes associated with ADHD symptoms

   Howard Chiu, Sila Genc, Charles B. Malpas, and 4 more authors

   Brain Disorders, Dec 2021

   Abs

   

   Children with attention-deficit/hyperactivity disorder (ADHD) have poor academic functioning compared to typically developing children, with executive dysfunction mediating the relationship between ADHD symptoms and academic outcomes. This study investigated whether differences in prefrontal and frontostriatal structures explain this mediating relationship. 132 children aged 9–11 years (mean 10.4 years) completed a MRI including structural and diffusion acquisitions. Cortical regions were parcellated using Freesurfer. Frontostriatal tracts were generated using constrained spherical deconvolution (CSD) tractography. Executive functioning was assessed using working memory, sustained attention and response inhibition tasks. Academic achievement was measured by direct assessment of reading and mathematics, teacher report of academic competence, and national standardized academic testing. Serial mediation analysis tested whether executive function and frontostriatal structures mediate the poorer academic functioning seen in ADHD. Symptom severity (predominantly inattention) was associated with poorer academic outcomes. Working memory partially mediated the relationship between symptoms and academic outcomes. In a serial mediation model, left DLPFC volume, right orbitofrontal volume, and left striatal structures to DLPFC tract volumes partially mediated academic outcome. This study suggests that variability in frontostriatal structures explain the mediating effect of cognitive performance on the relationship between ADHD symptomatology and academic outcomes.