Two-choice Reaction Time Task Research Articles

Stochastic resonance is not required for pink noise to have beneficial effects on ADHD-related performance? The Moderate Brain Arousal model challenged.

ObjectiveRandom noise, such as white or pink noise, has been shown to have beneficial effects on the performance of individuals with (elevated traits of) ADHD. Both the state regulation deficit (SRD) account and the moderate brain arousal (MBA) model argue that this effect is due to enhanced cognitive arousal. The MBA model specifically attributes this to random noise affecting dopaminergic (DA) transmission via stochastic resonance (SR). However, he requirement of SR and the role of DA have not yet been properly examined. To test this, proper control conditions are needed. MethodTo examine the requirement of SR, 60 neurotypical adults with varying levels of ADHD traits performed a slow two-choice reaction time (S1-S2) task in three auditory conditions: pink (random) noise, a pure 100 Hz tone (non-random noise), and silence. All participants also completed the Attention Network Test (ANT) in two conditions (pink noise and silence) to inspect the effect on executive network efficiency which may serve as a proxy measure of DA. ADHD traits were assessed via self-report. ResultsAuditory stimulation improved performance on the S1-S2 task in participants with elevated ADHD traits, however this was the case for both pink noise and the pure tone. Pink noise did not affect executive network efficiency, irrespective of ADHD traits. ConclusionsOur results suggest that stochastic resonance is not required for pink noise to have a beneficial effect on ADHD-related performance. Pink noise did not affect our DA proxy measure, however this negative finding should be interpreted with caution. Our results cast doubt on the tenets of the MBA model, warranting further research.

Practice-related changes in perceptual evidence accumulation correlate with changes in working memory.

It has been proposed that evidence accumulation determines not only the speed and accuracy of simple perceptual decisions but also influences performance on tasks assessing higher-order cognitive abilities, such as working memory (WM). Accordingly, estimates of evidence accumulation based on diffusion decision modeling of perceptual decision-making tasks have been found to correlate with WM performance. Here we use diffusion decision modeling in combination with latent factor modeling to test the stronger prediction that practice-induced changes in evidence accumulation correlate with changes in WM performance. Analyses are based on data from the COGITO Study, in which 101 young adults practiced a battery of cognitive tasks, including three simple two-choice reaction time tasks and three WM tasks, in 100 day-to-day training sessions distributed over 6 months. In initial analyses, drift rates were found to correlate across the three choice tasks, such that latent factors of evidence accumulation could be established. These latent factors of evidence accumulation were positively correlated with latent factors of practiced and unpracticed WM tasks, both before and after practice. As predicted, individual differences in changes of evidence accumulation correlated positively with changes in WM performance. Our findings support the proposition that decision making and WM both rely on the active maintenance of task-relevant internal representations. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

Examining the Mechanisms of Internal and External Focus of Attention With Donders’ Subtractive Method

The goal of the current study was to measure the processing demands on the stages of information processing with internal and external foci of attention. Participants completed simple and two-choice reaction time tasks with internal and external foci of attention. Donders' subtraction method was used to isolate the cumulative duration of stages unique to simple and choice reaction time tasks. Mean reaction time was comparable with internal and external foci of attention in simple and two-choice reaction time tasks. These results suggest that processing demands were comparable with internal and external foci of attention. We hypothesize that there was not a processing advantage for an external focus in simple reaction time because the required movements had low movement complexity.

Sharing motor plans while acting jointly: A TMS study

When acting together, we may represent not only our own individual goals but also a collective goal. Although behavioural evidence suggests that agents' motor plans might be related to collective goals, direct neurophysiological evidence of whether collective goals are motorically represented is still scarce. The aim of the present transcranial magnetic stimulation (TMS) study is to begin to fill this gap. A participant and a confederate were asked to sequentially perform a two-choice reaction time task by acting on pressure sensors. In their own turn, they saw a cue indicating whether to lift their fingers from (or to press them on) a pressure sensor to shoot a ball across the screen as fast as possible. The confederate responded with the right hand, the participant with the left hand. While the confederate acted on the sensor, the participant's motor evoked potentials (MEPs) were collected from the right Extensor Carpi Ulnaris. If participants represent their own and the confederate's actions as being directed to a collective goal, MEPs amplitude should be modulated according to the action the confederate should perform. To test this conjecture, we contrasted three conditions: a Joint condition, in which both players worked together with their collective goal being to shoot the ball to get it to a common target, a Parallel condition, in which the players performed exactly the same task but received independent outcomes for their performance, and a Competitive condition, in which the outcome of the game still depended on the other player performance, but without the collective goal feature. Results showed no MEPs modulation according to the confederate's action in the Joint condition. Post-hoc exploratory analyses both provide some hints about this negative finding and also suggest possible improvements (i.e., adopting a different dependent variable, avoiding task-switching between conditions) for testing our hypothesis that collective goal can be represented motorically.

Computational modeling reveals strategic and developmental differences in the behavioral impact of reward across adolescence.

Studies of reward effects on behavior in adolescence typically rely on performance metrics that confound myriad cognitive and non-cognitive processes, making it challenging to determine which process is impacted by reward. The present longitudinal study applied the diffusion decision model to a reward task to isolate the influence of reward on response caution from influences of processing and motor speed. Participants completed three annual assessments from early to middle adolescence (N=387, 55% female, Mage =12.1 at Wave 1; Mage =13.1 at Wave 2, Mage =14.1 at Wave 3) and three annual assessments in late adolescence (Mages =17.8, 18.9, 19.9). At each assessment, participants completed a two-choice reaction time task under conditions of no-reward and a block in which points were awarded for speeded accuracy. Reward reduced response caution at all waves, as expected, but had a greater impact as teens moved from early to middle adolescence. Simulations to identify optimal response caution showed that teens were overly cautious in early adolescence but became too focused on speed over accuracy by middle adolescence. By late adolescence, participants adopted response styles that maximized reward. Further, response style was associated with both internalizing and externalizing symptoms in early-to-middle adolescence, providing evidence for the construct validity of a diffusion model approach in this developmental period.

Functional brain imaging of speeded decision processing in Parkinson's disease and comparison with Schizophrenia

This study examined whether Parkinson's disease (PD11Parkinson Disease) and schizophrenia (SCZ22Schizophrenia) share a hypo dopaminergic dysfunction of the prefrontal cortex leading to cognitive impairments in decision processing. 24 medicated PD patients and 28 matched controls performed the Eriksen flanker two-choice reaction time (RT33Reaction Time) task while brain activity was measured throughout, using functional Magnetic Resonance Imaging (fMRI44functional Magnetic Resonance Imaging). Results were directly compared to those of 30 SCZ patients and 30 matched controls. Significant differences between SCZ and PD were found, through directly comparing the z-score deviations from healthy controls across all behavioral measures, where only SCZ patients showed deviances from controls. Similarly a direct comparison of z-score activation deviations from controls indicated significant differences in prefrontal and cingulate cortical activation between SCZ and PD, where only SCZ patients showed hypo-activation of these areas compared to controls. The hypo-activation of the dorsolateral prefrontal cortex was related to larger RT variability (ex-Gaussian tau) in SCZ but not PD patients. Overall, the concluding evidence does not support a shared neural substrate of cognitive dysfunction, since the deficit in speeded decision processing and the related cortical hypo-activation observed in SCZ were absent in PD.

Effect of perceived interpersonal closeness on the joint Simon effect in adolescents and adults

Here, we explored the role of perceived interpersonal closeness in joint action using the joint Simon task in adolescents and adults. In a two-choice reaction time task, spatially assigned responses to non-spatial stimulus features are faster when the stimulus and response are in congruent locations than not. This phenomenon is called Simon effect and is absent or strongly attenuated when a participant responds to only one of the stimuli. However, the effect reappears when two participants carry out the same go/no-go tasks cooperatively. This re-emergence of the Simon effect in joint action is called the joint Simon effect (JSE). In this study, we first replicated the standard and joint Simon effects in adolescents (n = 43), as well as adults (n = 39) with similar magnitude of the effects in the two age groups. The magnitude of the JSE was positively correlated with the level of closeness as measured by Inclusion of Other in the Self scale. This correlation was not significantly different in adolescents (n = 73) compared to adults (n = 71). Our findings show that joint action is sensitive to the social factor such as interpersonal closeness, and the underlying mechanisms are already mature by adolescence.

Saccadic eye movements in dual tasking: No impairment of spatial planning, but delayed execution of saccades.

In the target-distractor saccade task, a target and an irrelevant distractor are simultaneously presented and the task itself consists of a target-directed saccade. Findings usually show that as saccade latency increases, saccade trajectory deviation towards the distractor decreases. We presented this saccade task in two dual-task experiments to address the open question of whether performance of an auditory-manual task simply delays the temporal execution of a saccade, or whether it also interferes with the spatial planning of the saccade trajectory. We measured saccade latency, as a measure of a delay in execution, and saccade trajectory deviation, as a measure of the spatial planning. In Experiment 1, the auditory-manual task was a two-choice reaction time (two-CRT) task, and in Experiment 2, it was a go-no-go task. Performing the two tasks in close temporal succession shortly delayed the temporal execution of the saccade, but did not influence the spatial planning of the saccade trajectory. This result pattern was more pronounced when the auditory-manual task required the selection and execution of one of two possible manual responses (Experiment 1), less pronounced when the auditory-manual task required the decision to execute a button press (go condition, Experiment 2), and absent when the auditory-manual task required the decision to inhibit a button press (no-go condition, Experiment 2). Taken together, the manual response rather than the response selection process of the auditory-manual task led to a delay of saccade execution, but not to an impairment of the spatial planning of the saccade trajectory.

Visuo-Perceptual and Decision-Making Contributions to Visual Hallucinations in Mild Cognitive Impairment in Lewy Body Disease: Insights from a Drift Diffusion Analysis.

Background: Visual hallucinations (VH) are a common symptom in dementia with Lewy bodies (DLB); however, their cognitive underpinnings remain unclear. Hallucinations have been related to cognitive slowing in DLB and may arise due to impaired sensory input, dysregulation in top-down influences over perception, or an imbalance between the two, resulting in false visual inferences. Methods: Here we employed a drift diffusion model yielding estimates of perceptual encoding time, decision threshold, and drift rate of evidence accumulation to (i) investigate the nature of DLB-related slowing of responses and (ii) their relationship to visuospatial performance and visual hallucinations. The EZ drift diffusion model was fitted to mean reaction time (RT), accuracy and RT variance from two-choice reaction time (CRT) tasks and data were compared between groups of mild cognitive impairment (MCI-LB) LB patients (n = 49) and healthy older adults (n = 25). Results: No difference was detected in drift rate between patients and controls, but MCI-LB patients showed slower non-decision times and boundary separation values than control participants. Furthermore, non-decision time was negatively correlated with visuospatial performance in MCI-LB, and score on visual hallucinations inventory. However, only boundary separation was related to clinical incidence of visual hallucinations. Conclusions: These results suggest that a primary impairment in perceptual encoding may contribute to the visuospatial performance, however a more cautious response strategy may be related to visual hallucinations in Lewy body disease. Interestingly, MCI-LB patients showed no impairment in information processing ability, suggesting that, when perceptual encoding was successful, patients were able to normally process information, potentially explaining the variability of hallucination incidence.

Active Bilingualism in Aging: Balanced Bilingualism Usage and Less Frequent Language Switching Relate to Better Conflict Monitoring and Goal Maintenance Ability.

Experience-related neuroplasticity suggests that bilinguals who actively manage their two languages would develop more efficient neural organization at brain regions related to language control, which also overlap with areas involved in executive control. Our aim was to examine how active bilingualism-manifested as the regular balanced use of two languages and language switching-may be related to the different domains of executive control in highly proficient healthy older adult bilinguals, controlling for age, processing speed, and fluid intelligence. Participants were 76 community-dwelling older adults who reported being physically and mentally healthy and showed no signs of cognitive impairment. They completed a self-report questionnaire on their language background, two computer measures for previously identified covariates (processing speed as measured by two-choice reaction time (RT) task and fluid intelligence as measured by the Raven's Progressive Matrices), as well as a battery of computerized executive control tasks (Color-shape Task Switching, Stroop, Flanker, and Spatial 2-back task). Regression analyses showed that, even after controlling for age, processing speed, and fluid intelligence, more balanced bilingualism usage and less frequent language switching predicted higher goal maintenance (nonswitch trials RT in Color-shape Task Switching) and conflict monitoring abilities (global RT in Color-shape Task Switching and Flanker task). Results suggest that active bilingualism may provide benefits to maintaining specific executive control abilities in older adult bilinguals against the natural age-related declines.

Redundant visual signals reduce the intensity of alcohol impairment

BackgroundHumans interact with multiple stimuli across several modalities each day. The “redundant signal effect” refers to the observation that individuals respond more quickly to stimuli when information is presented as multisensory, redundant stimuli (e.g., aurally and visually), rather than as a single stimulus presented to either modality alone. Studies of alcohol effects on human performance show that alcohol induced impairment is reduced when subjects respond to redundant multisensory stimuli. However, redundant signals do not need to involve multisensory stimuli to facilitate behavior as studies have shown facilitating effects by redundant unisensory signals that are delivered to the “same sensory” (e.g., two visual or two auditory signals). MethodsThe current study examined the degree to which redundant visual signals would reduce alcohol impairment and compared the magnitude of this effect with that produced by redundant multisensory signals. On repeated test sessions, participants (n = 20) received placebo or 0.65 g/kg alcohol and performed a two-choice reaction time task that measured how quickly participants responded to four different signal conditions. The four conditions differed by the modality of the target presentation: visual, auditory, multisensory, and unisensory. ResultsAlcohol slowed performance in all conditions and reaction times were generally faster in the redundant signal conditions. Both multisensory and unisensory redundant signals reduced the impairing effects of alcohol compared with single signals. ConclusionsThese findings indicate that the ability of redundant signals to counteract alcohol impairment does not require multisensory input. Duplicate signals to the same modality can also reduce alcohol impairment.

Cardiovascular and Orthostatic Responses to a Festive Meal Associated With Alcohol in Young Men.

Aim: Sharing a festive meal associated with alcohol is quite common. While the cardiovascular changes occurring after meal ingestion of different nutrient composition has been well-established, the effects of ingesting a festive versus a standard meal accompanied with alcohol are less clear. Here, we compared the postprandial hemodynamics, cutaneous and psychomotor performance responses after ingestion of a classical Swiss festive meal [cheese fondue (CF)] versus a light ready-meal [Nasi Goreng (NG)], both accompanied with white wine.Methods: In a randomized cross over design, we examined in 12 healthy young men, the continuous cardiovascular, cutaneous, and reaction time responses to ingestion of cheese fondue versus a standard meal at rest (sitting position) and hemodynamic changes in response to orthostatic challenge (active standing) in pre- and postprandial phases.Results: Breath alcohol concentration after wine ingestion was similar after both meal types. Compared to the standard meal, consumption of CF induced higher increases in heart rate (HR), cardiac output (CO), double product (DP) and cardiac power output (CPO), greater vasodilation, and rises in skin blood flow and skin temperature. Greater increases in HR, DP, and mean blood pressure (MBP) were observed during orthostatic challenges with CF compared to NG. A two-choice reaction time task revealed similar reaction times with both meals, suggesting no influence of meal composition on psychomotor performance.Conclusion: In sitting position, CF ingestion induced a more important cardiovascular load compared to NG. Although the dose of alcohol and the festive meal used here did not lead to orthostatic hypotension, eating CF induced a greater cardiometabolic load suggesting that hemodynamic reserves have been encroached during active standing. This may impede the cardiovascular capacity during physical exercise or stress situations, particularly in elderly subjects who are at greater risk for postprandial hypotension and cardiovascular diseases.

The use of reaction time distributions to study attention in male rats: the effects of atomoxetine and guanfacine.

Norepinephrine (NE) is involved in the control of sustained attention. Studies of sustained attention in humans include measures of reaction time (RT) and RT variability (RTV). The present study tested the role of NE using components of the RT distribution in rats in a manner thought to be similar to human studies of RTV. This study tested the effects of increased synaptic NE (atomoxetine (ATX)) and α-2 receptor binding (guanfacine) on attentional lapses in rats. Male Sprague-Dawley rats (n = 20) were trained and tested in a two-choice RT task (2CRTT). Atomoxetine dose (saline, 0.1, 0.5, 1.0mg/kg, i.p.), guanfacine dose (saline, 0.01, 0.1, 0.3mg/kg, i.p.), and distractors were manipulated in three experiments. RT was divided into initiation time (IT) and movement time (MT). Analyses of distribution mode (peak) and deviation from the mode (skew) were then performed. ATX and guanfacine had no effect on IT mode, reduced IT devmode, and increased MT mode. When distractors were introduced, ATX again improved devmode, but a lack of interaction between ATX and distractor indicated that ATX did not prevent distractor-induced impairments. IT devmode is a measure of distribution skew thought to reflect lapses of attention. The effects of ATXon IT devmode suggest that increased synaptic NE reduces attentional lapses. These findings are consistent with human reports of reduced RTV after ATXadministration. The same pattern of results with guanfacine suggests that the effects of increased NE are due in part to binding at α-2 noradrenergic receptors.

Reaction time variability and attention-deficit/hyperactivity disorder: is increased reaction time variability specific to attention-deficit/hyperactivity disorder? Testing predictions from the default-mode interference hypothesis.

Increased reaction time variability (RTV) is one of the most replicable behavioral correlates of attention-deficit/hyperactivity disorder (ADHD). However, this may not be specific to ADHD but a more general marker of psychopathology. Here we compare RT variability in individuals with ADHD and those with other childhood internalizing and externalizing conditions both in terms of standard (i.e., the standard deviation of reaction time) and alternative indices that capture low-frequency oscillatory patterns in RT variations over time thought to mark periodic lapses of attention in ADHD. A total of 667 participants (6-12years old) were classified into non-overlapping diagnostic groups consisting of children with fear disorders (n = 91), distress disorders (n = 56), ADHD (n = 103), oppositional defiant or conduct disorder (ODD/CD; n = 40) and typically developing controls (TDC; n = 377). We used a simple two-choice reaction time task to measure reaction time. The strength of oscillations in RTs across the session was extracted using spectral analyses. Higher RTV was present in ADHD compared to all other disorder groups, effects that were equally strong across all frequency bands. Interestingly, we found that lower RTV to characterize ODD/CD relative to TDC, a finding that was more pronounced at lower frequencies. In general, our data support RTV as a specific marker of ADHD. RT variation across time in ADHD did not show periodicity in a specific frequency band, not supporting that ADHD RTV is the product of spontaneous periodic lapses of attention. Low-frequency oscillations may be particularly useful to differentiate ODD/CD from TDC.

Saving the Perruchet effect: A role for the strength of the association in associative learning.

In a partial reinforcement schedule where a cue repeatedly predicts the occurrence of a target in consecutive trials, reaction times to the target tend to decrease in a monotonic fashion, while participants' expectancies for the target decrease at the same time. This dissociation between reaction times and expectancies-the so-called Perruchet effect-challenges the propositional view of learning, which posits that human conditioned responses result from conscious inferences about the relationships between events. However, whether the reaction time pattern reflects the strength of a putative cue-target link, or only non-associative processes, such as motor priming, remains unclear. To address this issue, we implemented the Perruchet procedure in a two-choice reaction time task and compared reaction time patterns in an Experimental condition, in which a tone systematically preceded a visual target, and in a Control condition, in which the onset of the two stimuli were uncoupled. Participants' expectancies regarding the target were recorded separately in an initial block. Reaction times decreased with the succession of identical trials in both conditions, reflecting the impact of motor priming. Importantly, reaction time slopes were steeper in the Experimental than in the Control condition, indicating an additional influence of the associative strength between the two stimuli. Interestingly, slopes were less steep for participants who showed the gambler's fallacy in the initial block. In sum, our results suggest the mutual influences of motor priming, associative strength, and expectancies on performance. They are in line with a dual-process model of learning involving both a propositional reasoning process and an automatic link-formation mechanism.

ERP components associated with an indirect emotional stop signal task in healthy and depressed participants

Recent research has provided evidence to suggest that emotional stimuli may interfere with response inhibition, due to automatic capture of attention. Whilst previous studies have provided data regarding changes to event-related potentials (ERPs) in emotional Go/NoGo tasks, few studies to-date have utilized an emotional stop signal task (SST). Thirty-five participants were included in the study; 21 healthy controls and 14 depressed. An indirect emotional SST was employed, which consisted of the presentation of neutral, negative or positive visual images. The primary two-choice reaction time task required responding to frame colour (blue or green), whilst in 33% of trials an auditory stop signal was presented, with stop signal delay adjusted according to an adaptive tracking procedure. ERPs associated with both the primary visual task and the auditory SST were analysed using temporal principle components analysis (tPCA). In the primary task, reaction times were found to be slower for negative compared to neutral images. Stop signal reaction time (SSRT) was not found to be affected by image category or depression status. However, the NoGo-N2 component was found to be reduced for positive images, whilst the NoGo-P3 component was reduced for both positive and negative images in comparison to neutral images in the stop signal task. This effect was found to be enhanced for the depressed participants, indicating that inhibitory processing in the presence of positive stimuli may be inhibited to a greater extent in depressed individuals than in healthy controls. These findings provide further evidence for the ability of emotional valence and major depressive disorder to influence inhibitory processing.

Dissociated Components of Executive Control in Acute Hypobaric Hypoxia.

The neurocognitive effects of acute hypobaric hypoxia are still largely unknown. This study was designed to test the hypothesis that executive control, an important component of cognition, is especially vulnerable to hypoxia. Subjects participated in a simulated hypobaric chamber flight to 5500 m. Four auditory tasks were presented before, during, and after hypoxia: 1) Voice, and 2) Name variant of the Stroop task (both measuring conflict resolution); 3) go/no-go task (GNG; measuring inhibition); and 4) two-choice reaction time task (CRT; which is a noninhibitory control task). The Stroop effect increased during hypoxia: in the Voice Stroop it increased from 49.4 to 83.6 ms for reaction time and from 4.1 to 12.3% for accuracy; in the Name Stroop from 43.5 to 82.9 ms for reaction time (accuracy remained unchanged). Accuracy declined from 82.3 to 75.0% in CRT, and from 85.8 to 77.5% (averaged over stimulus types) in the GNG task. Importantly, accuracy decreased similarly to go and no-go stimuli in the GNG task, revealing unaffected inhibition. The findings suggest that tasks requiring conflict resolution are more likely to be impaired than tasks requiring inhibition of response. Furthermore, our results provide evidence for the distinct nature of inhibitory control functions.Takács E, Czigler I, Pató LG, Balázs L. Dissociated components of executive control in acute hypobaric hypoxia. Aerosp Med Hu Perform. 2017; 88(12):1081-1087.

Heading south with a north-up map: A choice processing analysis of map alignment effects

ABSTRACTThis study employed an information accumulation model of choice reaction times to investigate alignment effects in mental representations of maps. University students studied a map from a single orientation (with north at the top). In a subsequent two-choice reaction time task, the students’ spatial knowledge of the map was assessed employing spatial left/right judgments, which were made from imagined perspectives that were either north-aligned or south-aligned. Data showed a standard alignment effect, favoring north- over south-aligned trials. To examine the locus of this effect, data were fit using the Linear Ballistic Accumulator (LBA) model of speeded decisions (Brown & Heathcote, 2008). Of interest were three model parameters: drift rate, the speed at which evidence accumulates toward a response; response threshold, the amount of evidence demanded from the decision maker before selecting a response; and non-decision time, the time consumed by pre- and postdecisional processes. The best-fitting model suggested that non-decision time accounted for the alignment effect. The difference in non-decision time between north and south-aligned judgments suggests a mental alignment stage on south-aligned trials, accounting for the longer reaction times for judgements misaligned with the presented north orientation of the map.

Schizophrenia: An Impairment in the Capacity to Perceive Affordances.

Phenomenological psychopathologists conceptualize schizophrenia as a self-disorder involving profound distortions of selfhood. For James Gibson, “to perceive the world is to coperceive oneself.” If the sense of self is disturbed in individuals with schizophrenia, this could also lead to disturbances in these individuals’ ability to perceive affordances, environmental properties taken with reference to the perceiver’s action capabilities (e.g., a rigid surface affording ‘walk-on-able,’ chairs ‘sit-on-able,’ and so on). To test this hypothesis, three experiments investigated schizophrenia patients’ affordance perception. Participants were presented with a photo of a common object on the computer and then asked to judge its secondary affordance (a non-designed function) in a two-choice reaction time task in Experiment 1 and in a yes/no task in Experiment 2. Schizophrenia participants performed less accurately and more slowly than controls. To rule out visual impairment as a contributing factor, in Experiment 3, participants identified physical properties (color, shape, material composition) of the objects. Schizophrenia participants were as accurate as controls and responded faster than in the previous experiments. Results suggest that the capacity to perceive affordances is likely impaired in people with schizophrenia, although the capacity to detect the object’s physical properties is kept intact. Inability to perceive affordances, those functionally significant properties of the surrounding environment, may help explain why schizophrenia patients may appear as somewhat detached from the world.

Poor stimulus discriminability as a common neuropsychological deficit between ADHD and reading ability in young children: a moderated mediation model.

Attention deficit hyperactivity disorder (ADHD) is frequently associated with poorer reading ability; however, the specific neuropsychological domains linking this co-occurrence remain unclear. This study evaluates information-processing characteristics as possible neuropsychological links between ADHD symptoms and RA in a community-based sample of children and early adolescents with normal IQ (⩾70). The participants (n = 1857, aged 6-15 years, 47% female) were evaluated for reading ability (reading single words aloud) and information processing [stimulus discriminability in the two-choice reaction-time task estimated using diffusion models]. ADHD symptoms were ascertained through informant (parent) report using the Development and Well-Being Assessment (DAWBA). Verbal working memory (VWM; digit span backwards), visuospatial working memory (VSWM, Corsi Blocks backwards), sex, socioeconomic status, and IQ were included as covariates. In a moderated mediation model, stimulus discriminability mediated the effect of ADHD on reading ability. This indirect effect was moderated by age such that a larger effect was seen among younger children. The findings support the hypothesis that ADHD and reading ability are linked among young children via a neuropsychological deficit related to stimulus discriminability. Early interventions targeting stimulus discriminability might improve symptoms of inattention/hyperactivity and reading ability.