Time-Perception Deficits in Attention-Deficit/Hyperactivity Disorder: A Systematic Review and Meta-Analysis.

The present meta-analysis quantified the deficit in time perception in Attention-Deficit/Hyperactivity Disorder (ADHD) throughout the lifespan and examined potential moderators of this deficit. Our sample of 824 effect sizes showed a mean g of 0.688 that was moderated by the age of the sample and working memory. Separate moderator analyses for samples below or above the age of 18 showed that the link with working memory only applied to the samples below the age of 18, whereas an effect of ADHD subtype only applied to samples 18 and above. The discussion highlights the implications for remediation and avenues for future research.

Identifying spatial effects in a lateralized duration estimation task.

Spatial influences may be introduced to an experimental task by manipulations performed on the stimulus or the response or by virtue of the type of stimuli under study. Identification of spatial influences is especially pertinent in investigations of laterality, as isolation of processing to one hemisphere may inadvertently introduce spatial confounds. Because, however, space is not a relevant task feature, it may not always be obvious that it should be taken into consideration. Failure to anticipate these spatial influences can affect the conclusions drawn from results. The current work examines potential spatial influences in an experimental paradigm previously used to investigate perceptual asymmetries for duration estimation in which both stimulus presentation and response selection were lateralized. Potential spatial influences (including the spatial-temporal association of response codes - STEARC, spatial attention, and the Simon effect) are identified and systematically tested over 5 experiments. Results suggest that previously observed perceptual asymmetries in this experimental paradigm may be the result of a spatial confound, specifically, that of the Simon effect. Using vertical response options with the lateral stimulus presentation, however, mitigated the spatial influence. Altogether, the current work demonstrates the importance of carefully considering potential spatial confounds prior to commencement of laterality studies.

Expectation expands subjective duration for repeated stimuli by altering perception.

Repeated stimuli are generally perceived to be shorter in duration than novel stimuli. Matthews (2015), however, demonstrated that when repetition is predictable, expectations of repetition may expand subjective duration for repeated stimuli. Although this effect is hypothesised to be perceptual, this has yet to be empirically established. The present study, therefore, examined perceptual and decisional factors in the repetition effect by using psychophysical methods while varying probabilities of repetition, in addition to replicating Matthews' original paradigm. Using faces with neutral expressions, 60 participants completed 2 judgment tasks, indicating whether a comparison stimulus was longer or shorter in duration than a standard stimulus preceding it. Comparison stimuli were presented for the same duration as the 500-ms standard in the replication task and for 1 of 7 durations (from 200-1,250 ms) in the crucial extension task, allowing for examination of sensitivity and bias. No evidence of bias was observed, but modulating participants' expectations of repetition affected perception, such that discrimination was more difficult under high than low repetition conditions. Overall, participants were more likely to judge stimuli that met expectations as longer, regardless of whether the expectation was repetition or novelty. Implications for models of repetition, context effects, and time estimation are discussed. (PsycINFO Database Record (c) 2019 APA, all rights reserved).