Mechanisms of N-2 Repetition Costs and their Relationship to Inattention and Hyperactivity
Research Poster Social & Behavioral Sciences 2025 Graduate ExhibitionPresentation by Alexandra Roule
Exhibition Number 149
Abstract
Objective. N-2 repetition costs refer to an effect in which performance costs are higher when switching back to a recently performed task (A-B-A) than switching between novel tasks (C-B-A). These costs, driven by the inhibition of one task when moving to the next, decrease as more time is allotted for the inhibition of a previous task to dissipate. It remains unclear whether they also vary as a function of preparation time for the upcoming task. ADHD symptomology is often associated with inhibitory deficits- usually measured as the presence/absence of a response. Expanding research on inhibition in ADHD to N-2 repetition costs, we would also expect increased symptomology to predict lower costs. Method. Eighty-eight young adults (ages 18-30) completed two versions of the N-2 paradigm, in addition to questionnaires and a clinical interview evaluating inattention and hyperactivity as part of a larger neurocognitive study on attention problems. Paradigm 1 experimentally manipulated the time participants could prepare in advance of the stimulus (i.e. cue-to-stimulus interval; CSI). Paradigm 2 experimentally manipulated the time participants were given between trials (i.e. response-to-cue interval; RCI) to evaluate the mechanism of the dissipation effect. Performance was evaluated using diffusion modeling, which provides meaningful metrics of evidence accumulation rate and preparatory processing. Results. Preliminary results indicate that longer CSI and RCI reduce N-2 repetition costs, however counter to hypotheses, in both circumstances these reductions appear attributable to inhibitory dissipation. Similarly, higher inattention and hyperactivity ratings do not differentially predict N-2 repetition costs.
Importance
This study aims to disentangle the two processes involved in N-2 repetition costs: preparation and dissipation, which are easily experimentally confounded. The current study separates the experimental manipulation of CSI and RCI duration into two paradigms and uses evidence accumulation modeling to describe performance more meaningfully than frequently used measures of accuracy and reaction time. Given that the symptom and cognitive presentation of ADHD is often heterogenous and less understood in adults, this study also contributes to the cognitive literature on ADHD. By focusing on inhibitory control and task switching, two domains of executive functioning implicated in ADHD, this study seeks to determine how inhibitory control deficits may paradoxically, prevent the performance costs associated with N-2 repetition.