Instrumental learning and behavioral persistence in children with attention-deficit/hyperactivity-disorder: does reinforcement frequency matter?

After a Hand Was Lent: Sporadically Experiencing Multisensory Interference During the Rubber Hand Illusion Does Not Shield Against Disembodiment

Observations from multisensory body illusions indicate that the body representation can be adapted to changing task demands, e.g., it can be expanded to integrate external objects based on current sensorimotor experience (embodiment). While the mechanisms that promote embodiment have been studied extensively in earlier work, the opposite phenomenon of, removing an embodied entity from the body representation (i.e., disembodiment) has received little attention yet. The current study addressed this phenomenon and drew inspiration from the partial reinforcement extinction effect in instrumental learning which suggests that behavior is more resistant to extinction when reinforcement is delivered irregularly. In analogy to this, we investigated whether experiencing occasional visuo-motor mismatches during the induction phase of the moving rubber hand illusion (intermittent condition) would result in slower disembodiment as compared to a regular induction phase where motor and visual signals always match (continuous condition). However, we did not find an effect of reinforcement schedule on disembodiment. Keeping a recently embodied entity in the body schema, therefore, requires constant updating through correlated perceptual and motor signals.

Behavioral and Emotional Responding to Punishment in ADHD: Is Increased Emotionality Related to Altered Behavioral Responding?

Children with ADHD are theorized to experience increased negative emotional responses to punishment, compared to typically developing (TD) children, resulting in altered behavioral responding (Amsel, 1992). However, this has not been empirically tested. The current study evaluated the effects of punishment and reward on the behavioral and emotional responding of children with and without ADHD. Fifty-three children with ADHD (64.15% boys) and 46 TD children (47.83% boys), age 6-12, completed a task in which they chose between playing two simultaneously available games. Reward was arranged symmetrically across the games; responses on one game were punished four times as often as responses on the other game. Children's negative and positive emotional expressions were assessed during task completion with facial expression coding. Results indicated both groups showed a preference for playing the less punished game. Children with ADHD took longer to respond after punishment and reward compared to TD children. Negative emotional expressions increased with time on task for those with ADHD, the opposite pattern was seen in TD children. Children with ADHD showed more positive emotional expressions overall. The effect of ADHD on increased response times after reward was statistically fully mediated by increased positive facial expressions. Findings indicate children with ADHD do not show an altered response bias under punishment compared to TD children, but their cumulative negative emotional responding may indicate problems with building frustration tolerance as hypothesized by Amsel (1992). Results are theoretically important as they suggest increased emotional responding in ADHD is associated with slower responding.

Relationships between experimental task and questionnaire measures of reward/punishment sensitivity in attention-deficit/hyperactivity disorder (ADHD): protocol for a scoping review

INTRODUCTION

One of the purported underlying causal mechanisms of attention deficit hyperactivity disorder (ADHD) is altered motivational processes. Questionnaires have been used to identify the characteristics of reward and punishment sensitivity in individuals with ADHD. However, these questionnaires were initially developed to measure individual traits related to anxiety (inhibitory) and impulsivity (approach) tendencies or differences in pleasure-seeking. These reward and punishment sensitivity questionnaires are useful but might not capture all relevant aspects of altered motivational processes in ADHD. The proposed scoping review aims to: (1) examine which aspects of hypothesised altered reward and punishment sensitivity correspond to constructs measured by existing questionnaires, (2) characterise the relationships between ADHD symptomatology and reward and punishment sensitivity as measured by existing questionnaires and (3) evaluate the consistency between the altered reward and punishment sensitivity as measured by existing questionnaires and experimental task performance.

METHODS AND ANALYSIS

Reporting of the scoping review results will adhere to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews and the Joanna Briggs Methodology for Scoping Reviews. Published English-language literature was searched in three electronic databases (PubMed, Web of Science, APA PsycINFO) on 16 November 2023, with no restriction on the year of publication. Two researchers independently screened all identified titles/abstracts before proceeding to full-text review and additional handsearching of relevant studies. A narrative review and conclusions will be presented together with tables summarising the articles reviewed and the results organised by the three aims.

ETHICS AND DISSEMINATION

This study reviews existing publications with ethical approval in place. Therefore, ethical approval is not required. Review results will be disseminated through academic conferences and peer-reviewed manuscripts. Scoping review results will also inform future research to measure and identify altered motivational processes in ADHD.

Using rodent data to elucidate dopaminergic mechanisms of ADHD: Implications for human personality

An altered behavioral response to positive reinforcement has been proposed to be a core deficit in attention deficit hyperactivity disorder (ADHD). The spontaneously hypertensive rat (SHR), a congenic animal strain, displays a similarly altered response to reinforcement. The presence of this genetically determined phenotype in a rodent model allows experimental investigation of underlying neural mechanisms. Behaviorally, the SHR displays increased preference for immediate reinforcement, increased sensitivity to individual instances of reinforcement relative to integrated reinforcement history, and a steeper delay of reinforcement gradient compared to other rat strains. The SHR also shows less development of incentive to approach sensory stimuli, or cues, that predict reward after repeated cue-reward pairing. We consider the underlying neural mechanisms for these characteristics. It is well known that midbrain dopamine neurons are initially activated by unexpected reward and gradually transfer their responses to reward-predicting cues. This finding has inspired the dopamine transfer deficit (DTD) hypothesis, which predicts certain behavioral effects that would arise from a deficient transfer of dopamine responses from actual rewards to reward-predicting cues. We argue that the DTD predicts the altered responses to reinforcement seen in the SHR and individuals with ADHD. These altered responses to reinforcement in turn predict core symptoms of ADHD. We also suggest that variations in the degree of dopamine transfer may underlie variations in personality dimensions related to altered reinforcement sensitivity. In doing so, we highlight the value of rodent models to the study of human personality.

Poor learning or hyper-exploration?: A commentary on Hulsbosch et al. (2023)

In an outstanding paper, Hulsbosch et al. (Journal of Child Psychology and Psychiatry, 2023) tested major reinforcement learning theories of attention-deficit/hyperactivity disorder (ADHD). On a reinforcement learning task, children with ADHD needed more trials to reach the criterion in the learning phase and chose the target less often in the extinction phase. These results only partially support either of the theories and may be interpreted as reflecting a general deficit in learning. Still, distinguishing between learning and decision-making stages suggests that poor performance on reinforcement learning tasks by children with ADHD is accounted for by increased exploration or decreased choice consistency rather than deficient learning.