What happened to the Canada-United States brain drain of the 1990s? New evidence from the 2000 US census

This article uses the 2000 US Census to ascertain both quantitative and qualitative changes in Canadian immigrants to the United States through, the 1990s, and compares these to earlier migration cohorts from census data in 1980 and 1990. Canadians in the United States continue to have higher relative salaries and education levels vis-à-vis their American counterparts and this gap has widened in the 1990s, even when controlling for variety of labour market factors. A similar phenomenon occurred amongst immigrants from Britain and Ireland and suggests that US economic performance and immigration policy are the probable driving, force behind this migration.     

Unskilled, unaware, or both? The better-than-average heuristic and statistical regression predict errors in estimates of own performance

People who score low on a performance test overestimate their own performance relative to others, whereas high scorers slightly underestimate their own performance. J. Kruger and D. Dunning (1999) attributed these asymmetric errors to differences in metacognitive skill. A replication study showed no evidence for mediation effects for any of several candidate variables. Asymmetric errors were expected because of statistical regression and the general better-than-average (BTA) heuristic. Consistent with this parsimonious model, errors were no longer asymmetric when either regression or the BTA effect was statistically removed. In fact, high rather than low performers were more error prone in that they were more likely to neglect their own estimates of the performance of others when predicting how they themselves performed relative to the group.     

Perinatal infection, fetal inflammatory response, white matter damage, and cognitive limitations in children born preterm

Only sparse information is available about a possible association between antenatal infection outside the brain and subsequent cognitive limitations among preterm infants. Based on published studies, we provide a theoretical schema that links them via the fetal inflammatory response and neonatal white matter damage. We conclude that the relationship between antenatal infection and cognitive limitations deserves much further attention by researchers interested in the prevention of this undesirable outcome of prematurity.     

Dopamine modulates frontomedial failure processing of agentic introverts versus extraverts in incentive contexts

The agency facet of extraversion (aE) describes individual differences in goal-directed behavior and has been linked to dopamine function in incentive contexts. Because dopamine presumably modulates the processing of negative feedback/failure, aE may relate to failure processing in incentive contexts. To test this hypothesis, N = 86 participants performed a virtual ball-catching task. An incentive context was created by displaying potential rewards and subtle manipulations of task performance, which either was (control group) or was not (incentive context group) made explicit. To probe the involvement of dopamine, participants received either placebo or the selective dopamine D2 receptor antagonist sulpiride (200 mg). Failure processing was assessed through negative-feedback-evoked differences in the frontal midline theta electroencephalogram power (DFMT) and in the feedback-related negativity event-related potential component (FRN). Before incentives were introduced, DFMT (but not the FRN) was related to neuroticism/anxiety. Importantly, once incentives were displayed, aE was associated with DFMT, FRN, task performance, and changes in self-reported positive affect, which further depended on incentive context group and/or substance group: In the incentive context group but not in the control group, agentic extraverts showed relatively blunted DFMT after placebo. Sulpiride significantly enhanced DFMT, whereas it reduced FRN amplitudes and performance in agentic extra- versus introverts. These findings provide strong support for current dopamine models of aE and failure processing, and also highlight the importance of task context. Moreover, the dissociations of FRN and DFMT suggest the existence of two nonredundant electrophysiological indices of feedback processing, both relating to dopamine and aE.     

Parieto-occipital areas involved in efficient filtering in search: A time course analysis of visual marking using behavioural and functional imaging procedures

Search for a colour-form conjunction target can be facilitated by presenting one set of distractors prior to the second set of distractors and the target: the preview benefit (Watson & Humphreys, 1997). The early presentation of one set of distractors enables them to be efficiently filtered from search. We report two studies investigating the time course of the preview benefit. In Experiment 1 we use a standard reaction time analysis to show that the benefit has a relatively slow time course; old items need to precede the new set by 600 ms or more in order to be fully filtered from search. Furthermore, the reductions in reaction time across time in the preview condition varied nonlinearly with the display size, suggesting that old items were discounted from search in parallel. In Experiment 2 we examined the neural locus of this filtering effect over time, using positron emission tomography (PET). We show that regions of parieto-occipital cortex are selectively activated in a preview search condition relative to a detection baseline. These regions also increase in activation as the preview interval increases (and search then becomes easier), consistent with them modulating the parallel filtering of distractors from targets in spatial search. Interestingly, the same areas as those activated in preview search were also active in conjunction search relative to its own detection baseline. Thus these regions either modulate parallel filtering in conjunction search too, or they modulate different behavioural functions according to task constraints.     

Goethe’s Polarity of Light and Darkness

Rarely does research in the history and philosophy of science lead to new empirical results, but that is exactly what has happened in one of the essays of this special issue: Rang and Grebe-Ellis have developed new experimental techniques to perform measurements Goethe proposed 217 years ago. These measurements fit neatly with Goethe’s idea of polarity—his complementary spectrum is not only an optical, but also a thermodynamical counterpart of Newton’s spectrum. I use the new measurements, firstly, to argue against the asymmetries between light and darkness posited by Lyre and Schreiber; and, secondly, to explicate the alternative theory (the heterogeneity of darkness) that Goethe had introduced to urge scientific pluralism. In my replies to exegetical criticism by Böhler, Hampe and Zemplén, I show that the main goal of Goethe’s Farbenlehre was indeed to expose symmetries between light and darkness. Furthermore, I argue that it is worthwhile to focus on the experiments, arguments and hypotheses of the Farbenlehre, and not merely on rhetorical, narrative or stylistical aspects, as Böhler and Hampe would have it. Goethe’s criticism of Newton is often dismissed, but it is in fact surprisingly relevant today.     

Gendered norms for family size, employment, and occupation: Are there personal costs for violating them?

The present study investigated gendered stereotypes involving women’s family size, employment, and occupation. Eleven ratings of targets’ social and personality characteristics were ascribed by 400 undergraduates to a hypothetical married woman described as voluntarily childfree or the mother of one, two, or eight children, and as nonemployed or employed either part or full time in either a gender-appropriate or gender-inappropriate occupation. Women employed in gender-atypical occupations were considered less expressive and were socially distanced, but this factor did not interact with family size. Two-children mothers were regarded favorably as was employment. Prior findings denigrating single-child mothers and glorifying eight-children mothers were not replicated—both groups were rated similar to normative, two-children mothers. Consistent with prior research, childfree women were evaluated least favorably. Findings suggest that norms regarding both family size (two children) and employment exist among contemporary college students. The authors thank Pauline Beres for her help with data collection and entry. This paper was presented at the meeting of the American Psychological Association in New York in 1995.