A Study of Blocking and Overshadowing in Filial Imprinting

The occurrence of blocking and overshadowing in filial imprinting was investigated in junglefowl chicks (Gallus gallus spadiceus). When subjects were exposed to a novel object in the presence of a familiar one, imprinting on the novel object was impaired in one of two experimental groups (Experiment 1). When subjects were exposed to two objects from the beginning, imprinting on each object was impaired (Experiment 2). These results suggest that phenomena resembling blocking and overshadowing in conditioning may occur in imprinting. The fact that overshadowing was much more prevalent and convincing than blocking is discussed by referring to processes involved in the formation of internal representations. It is suggested that processes connecting these representations to the executive system of filial behaviour may follow the rules of associative learning.     

Colorblind or colorful? How diversity approaches affect cultural majority and minority employees

We examined how perceived organizational diversity approaches (colorblindness and multiculturalism) relate to affective and productive work outcomes for cultural majority and minority employees. Using structural equation modeling on data collected in a panel study among 152 native Dutch majority and 77 non‐Western minority employees, we found that perceptions of a colorblind approach were most strongly related to work satisfaction and perceived innovation for majority members, while perceptions of a multicultural approach “worked best” for minority members. Moreover, these effects were fully mediated by the extent to which employees felt socially included in the organization. Thus, while inclusion is an important factor for both groups to enhance work outcomes, it is facilitated by different diversity approaches for majority and minority members.     

There is no induced motion at near-threshold velocities

Duncker's classic experiments on induced motion at near-threshold velocities were based on the assumption that movement of one stimulus relative to the other (object-relative) is perfectly detected while it remains completely impossible to identify which of the two stimuli is moving (subject-relative). In the present experiments it is shown that the threshold areas of object-relative and subject-relative movement are largely overlapping. Consequently Dunker's assumption cannot be fulfilled: whenever object-relative movement is well detectable accuracy of detecting subject-relative motion will also be over 50%. In four additional experiments it is shown that the well-established effects of fixation, stimulus size and enclosure on induced motion are to be interpreted as effects of these variables on the detection of subject-relative movement: the so-called induction phenomena occured only when accuracy was over 50%.     

The perception of pure and mistuned musical fifths and major thirds: Thresholds for discrimination,beats, and identification

In Experiment 1, the discriminability of pure and mistuned musical intervals consisting of simultaneously presented complex tones was investigated. Because of the interference of nearby harmonics, two features of beats were varied independently: (1) beat frequency, and (2) the depth of the level variation. Discrimination thresholds (DTs) were expressed as differences in level (AL) between the two tones. DTs were determined for musical fifths and major thirds, at tone durations of 250, 500, and 1,000 msec, and for beat frequencies within a range of .5 to 32 Hz. The results showed that DTs were higher (smaller values of ΔL) for major thirds than for fifths, were highest for the lowest beat frequencies, and decreased with increasing tone duration. Interaction of tone duration and beat frequency showed that DTs were higher for short tones than for sustained tones only when the mistuning was not too large. It was concluded that, at higher beat frequencies, DTs could be based more on the perception of interval width than on the perception of beats or roughness. Experiments 2 and 3 were designed to ascertain to what extent this was true. In Experiment 2, beat thresholds (BTs) for a large number of different beat frequencies were determined. In Experiment 3, DTs, BTs, and thresholds for the identification of the direction of mistuning (ITs) were determined. For mistuned fifths and major thirds, sensitivity to beats was about the same. ITs for fifths and major thirds were not significantly different; deviations from perfect at threshold ranged from about 20 to 30 cents. Comparison of the different thresholds revealed that DTs are mainly determined by sensitivity to beats. Detailed analysis, however, indicated that perception of interval width is a relevant aspect in discrimination, especially for the fifths.     

The role of general and number-specific order processing in adults’ arithmetic performance

Digit order processing is highly related to individual differences in arithmetic performance. To examine whether serial scanning or associative mechanisms underlie order processing, order tasks (i.e. deciding whether three digits were presented in an order or not) were administered in two experiments. In the first experiment, digits were presented in different directions namely ascending, descending and non-ordered. For each direction, close and far distance sequences were presented. Results revealed reversed distance effects for ordered sequences, but ascending sequences elicited faster performance and stronger reversed distance effects than descending sequences, suggesting that associative mechanisms underlie order processing. In the second experiment, it was examined to which extent the relation between order processing and arithmetic is number-specific by presenting order tasks with digits, letters and months. In all order tasks similar distance effects were observed and similar relations with arithmetic were found, suggesting that both general associative mechanisms and number-specific mechanisms contribute to arithmetic.     

Protean attitude and career success: The mediating role of self-management

A protean career attitude is considered as an important determinant of career success in the contemporary career era. In this article we test a model in which we specify the relationships between protean career attitude, career self-management behaviors, career insight, and career success outcomes (career satisfaction and perceived employability). A survey was conducted among a sample of 289 employees. The results support the idea that a protean career attitude is a significant antecedent of career success and that this relationship is fully mediated by the development of career insight. The implications of these findings for understanding the process through which career attitude affects individuals’ career success are discussed.     

Under the Spell of the Ring

Among orthodox reformed Christians in the Netherlands fierce debates have occurred on moral aspects of Christian life. This essay discusses three major controversial moral issues that are related to conceptions of sex, gender, and sexuality: divorce/remarriage, women’s ordination, and homosexuality. By analysing several contributions to debates on these issues, it proposes and explores a hypothesis that concerns the role of a particular understanding of marriage as characterized by a hermeneutical construct: a communal, deeply rooted and subconscious normative principle that drives our interpretations of texts and practices. This essay illustrates the problems of both the dominance of marriage within Christian communities and lived faith, as well as the modern, romantic aspects of this particular understanding of marriage.