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Reinforcement learning tasks are often used to assess participants' tendency to learn more from the positive or more from the negative consequences of one's action. However, this assessment often requires comparison in learning performance across different task conditions, which may differ in the relative salience or discriminability of the stimuli associated with more and less rewarding outcomes, respectively. To address this issue, in a first set of studies, participants were subjected to two versions of a common probabilistic learning task. The two versions differed with respect to the stimulus (Hiragana) characters associated with reward probability. The assignment of character to reward probability was fixed within version but reversed between versions. We found that performance was highly influenced by task version, which could be explained by the relative perceptual discriminability of characters assigned to high or low reward probabilities, as assessed by a separate discrimination experiment. Participants were more reliable in selecting rewarding characters that were more discriminable, leading to differences in learning curves and their sensitivity to reward probability. This difference in experienced reinforcement history was accompanied by performance biases in a test phase assessing ability to learn from positive vs. negative outcomes. In a subsequent large-scale web-based experiment, this impact of task version on learning and test measures was replicated and extended. Collectively, these findings imply a key role for perceptual factors in guiding reward learning and underscore the need to control stimulus discriminability when making inferences about individual differences in reinforcement learning.

This paper studied whether abnormal P3 amplitudes in PDD are a corollary of abnormalities in ERP components related to selective attention in visual and auditory tasks. Furthermore, this study sought to clarify possible age differences in such abnormalities. Children with PDD showed smaller P3 amplitudes than controls, but no abnormalities in selective attention. Adolescents with PDD showed abnormal selective attention, as reflected by larger auditory Processing Negativity (PN) and visual N2b, but no P3 abnormalities. Dipole localizations revealed that the locations of PN generators in subjects with PDD differed from controls. It was concluded that the abnormalities in selective attention in adolescents with PDD have a normalizing effect on P3, and possibly act as a compensatory process.

Objective: We experimentally test the effect of cognitive load on auditory susceptibility during automated driving. Background: In automated vehicles, auditory alerts are frequently used to request human intervention. To ensure safe operation, human drivers need to be susceptible to auditory information. Previous work found reduced susceptibility during manual driving and in a lesser amount during automated driving. However, in practice, drivers also perform nondriving tasks during automated driving, of which the associated cognitive load may further reduce susceptibility to auditory information. We therefore study the effect of cognitive load during automated driving on auditory susceptibility. Method: Twenty-four participants were driven in a simulated automated car. Concurrently, they performed a task with two levels of cognitive load: repeat a noun or generate a verb that expresses the use of this noun. Every noun was followed by a probe stimulus to elicit a neurophysiological response: the frontal P3 (fP3), which is a known indicator for the level of auditory susceptibility. Results: The fP3 was significantly lower during automated driving with cognitive load compared with without. The difficulty level of the cognitive task (repeat or generate) showed no effect. Conclusion: Engaging in other tasks during automated driving decreases auditory susceptibility as indicated by a reduced fP3. Application: Nondriving task can create additional cognitive load. Our study shows that performing such tasks during automated driving reduces the susceptibility for auditory alerts. This can inform designers of semi-automated vehicles (SAE levels 3 and 4), where human intervention might be needed. [ABSTRACT FROM AUTHOR]

Keywords: driving; methylphenidate; ADHD 230 Original PapersMethylphenidate significantly improves driving performance of adults with attention-deficit hyperactivity disorder: a randomized crossover trial SAGE Publications, Inc.200810.1177/0269881107082946 Joris CVerster Section Psychopharmacology, Faculty of [...]