Dopaminergic and prefrontal contributions to reward-based learning and outcome monitoring during child development and aging

In many instances, children and older adults show similar difficulties in reward-based learning and outcome monitoring. These impairments are most pronounced in situations in which reward is uncertain (e.g., probabilistic reward schedules) and if outcome information is ambiguous (e.g., the relative value of outcomes has to be learned). Furthermore, whereas children show a greater sensitivity to external outcome information, older adults focus less on a rapid differentiation of rewarding outcomes. In this article, we review evidence for the idea that these phenomenologically similar impairments in learning and outcome monitoring in children and older adults can be attributed to deficits in different underlying neurophysiological mechanisms. We propose that in older adults learning impairments are the result of reduced dopaminergic projections to the ventromedial prefrontal cortex, which lead to less differentiated representations of reward value. In contrast, in children, impairments in learning can be primarily attributed to deficits in executive control, which may be due to a protracted development of the dorsal medial and lateral prefrontal cortices. We think that this framework maps well onto recent neurophysiological models of reward processing and is plausible from a broader developmental perspective.     

Development of adolescents' peer crowd identification in relation to changes in problem behaviors

This 5-wave longitudinal study, which included 1,313 Dutch adolescents, examined the development of peer crowd identification in relation to changes in problem behaviors. Adolescents from 2 age cohorts annually reported their identification with 7 peer crowds and their levels of internalizing and externalizing problem behaviors. Univariate latent growth curve analyses revealed declines (i.e., "Hip Hoppers" and "Metal Heads") or declines followed by stabilization (i.e., "Nonconformists") in identification with nonconventional crowds and increases (i.e., "Elites" and "Brains") or declines followed by stabilization (i.e., "Normals" and "Jocks") in identification with conventional crowds. Multivariate latent growth curve analyses indicated that stronger and more persistent identifications with nonconventional crowds were generally associated with more problem behaviors throughout adolescence. In contrast, stronger and more persistent identifications with conventional crowds were generally associated with fewer problem behaviors throughout adolescence with the notable exception of Brains, who showed a mixed pattern. Though characterized by fewer externalizing problems, this group did report more anxiety problems. These findings and their implications are discussed.     

Differences between Chinese morphosyllabic and German alphabetic readers in the Stroop interference effect

The goal of our study was to localize the source of the stronger Stroop interference effect found in morphosyllabic readers as compared with alphabetic readers. Twenty-three Chinese and 24 German undergraduate students were tested in a Stroop paradigm with the following stimuli: color patches, colorneutral words (e.g.,friend printed in yellow), incongruent color-associated words (e.g.,blood printed in blue), and incongruent color words (e.g.,yellow printed in blue). Results revealed no differences in German and Chinese students’ response times to color patches. Chinese participants, however, showed longer color naming latencies for neutral words as well as for color words and color-related words. No differences between German and Chinese participants were found when print color latencies for neutral words were subtracted from print color latencies for color words and color-related words. This result does not support theories which suggest that for morphosyllabic readers there is a direct route from orthography to the semantics of a word. We rather argue, with reference to dual route models of reading, that access from print to phonology is faster for morphosyllabic than for alphabetic readers, and therefore interference caused by conflicting phonologies of color name and written word will be stronger in Chinese readers than in German readers.     

Epistemic Norms and Democracy: a Response to Talisse

John Rawls argued that democracy must be justifiable to all citizens; otherwise, a democratic society is oppressive to some. In A Pragmatist Philosophy of Democracy ( 2007 ), Robert B. Talisse attempts to meet the Rawlsian challenge by drawing from Charles S. Peirce's pragmatism. This article first briefly canvasses the argument of Talisse's book and then criticizes its key premise concerning (normative) reasons for belief by offering a competing reading of Peirce's “The Fixation of Belief” ( 1877 ). It then proceeds to argue that Talisse's argument faces a dilemma: his proposal of epistemic perfectionism either is substantive and can be reasonably disagreed about or is minimal but insufficient to ground a democratic society. Consequently, it suggests that the Rawlsian challenge can only be solved by abandoning Rawls's own notion of reasonableness, and that an interesting alternative notion of reasons can be derived from Peirce's “Fixation.”     

Empathy, values, morality and Asperger's syndrome

The aims of this study were, first, to re-address the issue of empathy among people with autism conditions; second, to explore the relationships between empathy and values among autistic populations and controls; and third, to explore the capacity for moral agency among those affected by autism. We compared responses of an Asperger group (N = 41) and a control group (N = 139) to measures of self-reported empathy (Davis's IRI) and value priorities (Schwartz's PVQ). Control group results were largely in line with previous studies, such that empathy subscales of perspective taking and empathic concern showed their strongest positive and negative relations to the Schwartz self-transcendence/self-enhancement dimensions. Results for the Asperger group showed that although on the one hand there were self-reported difficulties in perspective taking and the cognitive recognition of affect, and that on the other hand there were less connections between the empathy and value measures, there was nevertheless a comparable prioritization of moral values. Conclusions suggest that different people may acquire moral values through different mechanisms.     

Switching in the cocktail party: exploring intentional control of auditory selective attention

Using a novel variant of dichotic selective listening, we examined the control of auditory selective attention. In our task, subjects had to respond selectively to one of two simultaneously presented auditory stimuli (number words), always spoken by a female and a male speaker, by performing a numerical size categorization. The gender of the task-relevant speaker could change, as indicated by a visual cue prior to auditory stimulus onset. Three experiments show clear performance costs with instructed attention switches. Experiment 2 varied the cuing interval to examine advance preparation for an attention switch. Experiment 3 additionally isolated auditory switch costs from visual cue priming by using two cues for each gender, so that gender repetition could be indicated by a changed cue. Experiment 2 showed that switch costs decreased with prolonged cuing intervals, but Experiment 3 revealed that preparation did not affect auditory switch costs but only visual cue priming. Moreover, incongruent numerical categories in competing auditory stimuli produced interference and substantially increased error rates, suggesting continued processing of task-relevant information that often leads to responding to the incorrect auditory source. Together, the data show clear limitations in advance preparation of auditory attention switches and suggest a considerable degree of inertia in intentional control of auditory selection criteria.     

Representational momentum in aviation

The purpose of this study was to examine the effects of expertise on motion anticipation. We conducted 2 experiments in which novices and expert pilots viewed simulated aircraft landing scenes. The scenes were interrupted by the display of a black screen and then started again after a forward or backward shift. The participant's task was to determine whether the moving scene had been shifted forward or backward. A forward misjudgment of the final position of the moving scene was interpreted as a representational momentum (RM) effect. Experiment 1 showed that an RM effect was detected only for experts. The lack of motion anticipation on the part of novices is a surprising result for the RM literature. It could be related to scene unfamiliarity, encoding time, or shift size. Experiment 2 was run with novices only. It was aimed at testing the potential impact of 2 factors on the RM effect: scene encoding time and shift size. As a whole, the results showed that encoding time and shift size are important factors in anticipation processes in realistic dynamic situations.     

Diagnosing fatigue in gait patterns by support vector machines and self-organizing maps

The aim of the study was to train and test support vector machines (SVM) and self-organizing maps (SOM) to correctly classify gait patterns before, during and after complete leg exhaustion by isokinetic leg exercises. Ground reaction forces were derived for 18 gait cycles on 9 adult participants. Immediately before the trials 7–12, participants were required to completely exhaust their calves with the aid of additional weights (44.4 ± 8.8 kg). Data were analyzed using: (a) the time courses directly and (b) only the deviations from each individual’s calculated average gait pattern. On an inter-individual level the person recognition of the gait patterns was 100% realizable. Fatigue recognition was also highly probable at 98.1%. Additionally, applied SOMs allowed an alternative visualization of the development of fatigue in the gait patterns over the progressive fatiguing exercise regimen.     

The unconscious pursuit of emotion regulation: implications for psychological health

Because of the central involvement of emotion regulation in psychological health and the role that implicit (largely unconscious) processes appear to play in emotion regulation, implicit emotion-regulatory processes should play a vital role in psychological health. We hypothesised that implicitly valuing emotion regulation translates into better psychological health in individuals who use adaptive emotion-regulation strategies. A community sample of 222 individuals (56% women) who had recently experienced a stressful life event completed an implicit measure of emotion regulation valuing (ER-IAT) and reported on their habitual use of an important adaptive emotion-regulation strategy: cognitive reappraisal. We measured three domains of psychological health: well-being, depressive symptoms, and social adjustment. As hypothesised, individuals who implicitly valued emotion regulation exhibited greater levels of psychological health, but only when they were high in cognitive reappraisal use. These findings suggest that salutary effects of unconscious emotion-regulation processes depend on its interplay with conscious emotion-regulation processes.