Methylphenidate slows reactions of children with attention deficit disorder during and after an error

A Sternberg memory search task was administered under placebo and methylphenidate to 42 children with cross-situational attention deficit disorder (ADD), 31 children with cross-situational ADD plus oppositional features, and 25 patients with marginal ADD. Overall, stimulant medication enhanced accuracy and speed. In addition, patients reacted faster on correct responses not preceded by an error than on errors (especially false alarms) or on correct responses following an error. The slowness during error reactions may reflect decreased confidence or confusion during stimulus classification. This uncertainty may also lead subjects to respond with greater caution, hence more slowly, on correct responses following errors. Notably, methylphenidate increased the slowing of reactions on error trials as well as on correct reactions following an error. Stimulant medication may augment subjects' persistence when they are uncertain or confused, thereby heightening caution and promoting accuracy on succeeding trials. Consistent with previous reports of the generality of enhancement of performance by stimulant medication, the impact of methylphenidate was comparable for the three subtypes of ADD studied.Jaine Strauss is at Macalester College.This research was supported by National Institute of Mental Health Grants MH32103 and MH38118. We thank Rachel Avery, Christine Carriuolo, Lawrence Ota, the late Helen Pollock, and the University of Rochester's Strong Memorial Hospital Pharmacy for their assistance.     

On being more than just a part of the whole: Regional identity and social distinctiveness

This article reports the results of a questionnaire study that examined the relationship between regional identification and perceptual accentuation of ingroup distinctiveness in a natural field setting. Respondents were male inhabitants of the Saarland which is a small German state. Half the respondents were members of the leading political party of the Saarland, while the other respondents were members of the major opposition party. As expected, the former showed more pronounced regional identification than the latter. Our main prediction was that a higher level of regional identification would be accompanied by stronger accentuation of positive distinctiveness of the regional ingroup relative to the national ingroup. The prediction was confirmed, both in terms of intergroup differentiation and perceived group homogeneity. Additional results suggest that, depending on the level of social identification, perceived group homogeneity may be either positively or negatively related to familiarity with the ingroup. Finally, we discuss the applicability of social identity theory to social contexts comprising differentially inclusive ingroups instead of mutually exclusive ingroups and outgroups.     

The perception of ingroup and outgroup homogeneity: On the confounding of group size,level of abstractness and frame of reference. A reply to Bartsch and Judd

In this reply, I criticize Bartsch and Judd's (1993) article on several grounds. First, they under-utilize the efforts undertaken in prior work to rule out the possibility of an inverse relation between group size and perceived group homogeneity as an alternative explanation of the observed ingroup homogeneity effect. Secondly, Bartsch and Judd's design doubles and thus aggravates the confounding problem. By trying to avoid the target group size confound, they end up with two other confounds involving level of abstractness and frame of reference. Finally, I criticize Bartsch and Judd's methodological advice to avoid within-subjects comparisons of ingroup and outgroup homogeneity in minority–majority contexts. Quite on the contrary, I highlight the socialpsychological significance of these comparisons.     

Ist Die Limes-Theorie Der Wahrscheinlichkeit Eine Sinnvolle Idealisation?

Ohne Zusammenfassung     

Simulation of motor-neuronal networks

This research develops a theoretical connectionist-type model of the operation of the human motor system. The model includes the operation of the cerebral cortex, pons, spinal cord, and muscles. It emphasizes the parallel passage of neuronal signals, the integration of multiple signals within nuclei, and the modulation of signals as a result of sensory input. A redundant Fast Fourier Transform (FFT) procedure that analyzes EEG signals by a method similar to the one used by pontine nuclei is described.     

The influence of stereotypes on decisions to shoot

Using a videogame to simulate encounters with potentially hostile targets, three studies tested a model in which racial bias in shoot/don't-shoot decisions reflects accessibility of the stereotype linking Blacks to danger. Study 1 experimentally manipulated the race-danger association by asking participants to read newspaper stories about Black (vs. White) criminals. As predicted, exposure to stories concerning Black criminals increased bias in the decision to shoot. Studies 2 and 3 manipulated the number of White and Black targets with and without guns in the context of the videogame itself. As predicted, frequent presentation of stereotypic (vs. counterstereotypic) targets exacerbated bias (Study 2) and—consistent with our process account—rendered stereotypes more accessible (Study 3). Copyright © 2007 John Wiley & Sons, Ltd.     

A Censored Mixture Model for Modeling Risk Taking

Psychometrika - Risk behavior has substantial consequences for health, well-being, and general behavior. The association between real-world risk behavior and risk behavior on experimental tasks is...