Nonlinear epigenetic variance: review and simulations

We present a review of empirical evidence that suggests that a substantial portion of phenotypic variance is due to nonlinear (epigenetic) processes during ontogenesis. The role of such processes as a source of phenotypic variance in human behaviour genetic studies is not fully appreciated. In addition to our review, we present simulation studies of nonlinear epigenetic variance using a computational model of neuronal network development. In each simulation study, time series for monozygotic and dizygotic twins were generated and analysed using conventional behaviour genetic modelling. In the results of these analyses, the nonlinear epigenetic variance was subsumed under the non-shared environmental component. As is commonly found in behaviour genetic studies, observed heritabilities and unique environmentabilities increased with time, whereas common environmentabilities decreased. The fact that the phenotypic effects of nonlinear epigenetic processes appear as unsystematic variance in conventional twin analyses complicates the identification and quantification of the ultimate genetic and environmental causes of individual differences. We believe that nonlinear dynamical system theories provide a challenging perspective on the development of individual differences, which may enrich behaviour genetic studies.     

Sexual Difference and Decolonization: Oyĕwùmí and Irigaray in Dialogue about Western Culture

In this article we aim to show the potential of cross‐continental dialogues for a decolonizing feminism. We relate the work of one of the major critics of the Western metaphysical patriarchal order, Luce Irigaray, to the critique of the colonial/modern gender system by the Nigerian feminist scholar Oy?rónké Oy?wùmí. Oy?wùmí's work is often rejected based on the argument that it is empirically wrong. We start by problematizing this line of thinking by providing an epistemological interpretation of Oy?wùmí's claims. We then draw Irigaray and Oy?wùmí into conversation, and show how this bolsters and helps to further illuminate and contextualize Oy?wùmí's critique of gender. But the dialogue between these thinkers also reveals significant limitations of Irigaray's philosophy, namely her presumption of the priority of sexual difference, its rigid duality, and her failure to take into account the inextricable intertwinement of gender and race in the Western patriarchal order. Relating Irigaray's critique of Western culture's forgetting of sexual difference to Oy?wùmí's critique hence demonstrates to what extent Irigaray's philosophy remains typically Western and how she therefore fails to escape the paradigm that she is so critical of.     

We all live in Germany but … Ingroup projection,group‐based emotions and prejudice against immigrants

Immigration, cultural diversity and integration are among the most central challenges for modern societies. Integration is often impeded by negative emotions and prejudices held by the majority members towards immigrants in a common society. Based on the ingroup projection model (Mummendey & Wenzel, 1999), we examined the impact of perceived relative ingroup prototypicality on intergroup emotions and prejudice. Additionally, we examined whether this impact is causal and explored the issue of causality in more detail contrasting a linear causal model with bi‐directional or reciprocal causality. Hypotheses were tested in a study with a two‐wave panel of majority members (N=1085) in Germany. We examined the proposed relations between relative ingroup prototypicality, intergroup emotions and prejudice and determined the causal direction of these relationships. Results support the predictive power of relative ingroup prototypicality on intergroup emotions and prejudice. Moreover, most causal relations between our measures are reciprocally causal. We discuss the implications of these findings for the general conception of prejudice and intergroup emotions. Copyright © 2009 John Wiley & Sons, Ltd.     

Linking dynamical perceptual decisions at different levels of description in motion pattern formation: psychophysics

The relationship between local-level motion detection and higher level pattern-forming mechanisms was investigated with the motion quartet, a bistable stimulus for which either horizontal or vertical motion patterns are perceived. Local-level perturbations in luminance contrast affected the stability of the perceived patterns and, thereby, the size of the pattern-level hysteresis obtained by gradually changing the motion quartet's aspect ratio. Briefly eliminating luminance contrast (so nonmotion was perceived during the perturbation) eliminated pattern-level hysteresis, and briefly increasing luminance contrast (so motion was perceived during the perturbation) increased pattern-level hysteresis. Partially reducing luminance contrast resulted in bistability during the perturbation; pattern-level hysteresis was maintained when motion was perceived, and eliminated when nonmotion was perceived. The results were attributed to local motion/nonmotion perceptual decisions in area V1 affecting the magnitude of the activation feeding forward to motion detectors in area MT, where the stability of pattern-level perceptual decisions is determined by activation-dependent, future-shaping interactions that inhibit soon-to-be-stimulated detectors responsive to competing motion directions.     

Can we predict mathematical learning disabilities from symbolic and non‐symbolic comparison tasks in kindergarten? Findings from a longitudinal study

Background. The ability to compare numbers, as the most basic form of number sense, has been related to arithmetical achievement. Aims. The current study addressed the predictive value of non‐symbolic and symbolic (number word (NW) and Arabic number (AN)) comparison for arithmetics by means of a longitudinal design. Sample. Sixteen children with mathematical disabilities (MD), 64 low achievers (LA), and 315 typical achieving (TA) children were followed from kindergarten till grade 2. Method. The association of comparison skills with arithmetical skills in grades l and 2 was studied. The performances of MD, LA and TA children were compared. Results. Regression analyses showed that non‐symbolic skills in kindergarten were predictively related to arithmetical achievement 1 year later and fact retrieval 2 years later. AN comparison was predictively related to procedural calculation 2 years later. In grade 2, there was an association between both symbolic tasks and arithmetical achievement. Children with MD already had deficits in non‐symbolic and symbolic AN comparison in kindergarten, whereas in grade 2 the deficits in processing symbolic information remained. Conclusions. The combination of non‐symbolic and symbolic deficits represents a risk of developing MD.     

Gaze aversion during social interaction in preterm infants: a function of attention skills?

Preterm infants avert their gaze more often and for longer periods in early social interactions compared to full term infants. In previous studies this finding is interpreted as being a function of the higher degree of parental stimulation that is often found in parents of preterm children. The current study explores an additional hypothesis. Since the development of general visual attention abilities is found to be less optimal in preterm children, it is possible that less optimal maturation of attention abilities partially explains the elevated gaze aversion in a social context. Therefore, the current study investigated the association between gaze aversion in a social context and the ability to disengage and shift visual attention in a non-social context in 20 preterm and 42 full term infants aged 4 and 6 months. Results confirm that preterm infants are slower to shift their attention in a non-social context and that they avert their gaze more often in a social context compared to full term children. Furthermore, more frequent gaze aversion during social interaction at 6 months was related to longer disengagement and the shifting of attention at 4 and 6 months, but only within the preterm group. The results suggest that attention maturation is less optimal in preterm children; this can be observed in a non-social as well as a social context. Less attention maturation in preterm children can negatively influence the amount of time they can stay actively involved in social interaction.     

The relationship between acculturation preferences and prejudice: Longitudinal evidence from majority and minority groups in three European countries

A longitudinal field survey tested the reciprocal effects of acculturation preferences and prejudice among ethnic minorities and majorities. Data were collected at two points in time from 512 members of ethnic minorities and 1143 majority members in Germany, Belgium and England. Path analyses yielded not only the lagged effects of prejudice on acculturation preferences but also the reverse for both majority and minority members. The mutual longitudinal effects between prejudice and desire for culture maintenance were negative, and the mutual effects between prejudice and desire for culture adoption were positive for majority members. The reverse was the case for minority participants. Moreover, the two acculturation dimensions interacted in their effect on prejudice for majority participants but not for minority participants. The effect of desire for culture adoption on prejudice was moderated by perceived intergroup similarity. Theoretical and practical implications of the findings are discussed. Copyright © 2014 John Wiley & Sons, Ltd.