Geometric analogue of holographic reduced representation

Holographic reduced representations (HRRs) are distributed representations of cognitive structures based on superpositions of convolution-bound n-tuples. Restricting HRRs to n-tuples consisting of ±1, one reinterprets the variable binding as a representation of the additive group of binary n-tuples with addition modulo 2. Since convolutions are not defined for vectors, the HRRs cannot be directly associated with geometric structures. Geometric analogues of HRRs are obtained if one considers a projective representation of the same group in the space of blades (geometric products of basis vectors) associated with an arbitrary n-dimensional Euclidean (or pseudo-Euclidean) space. Switching to matrix representations of Clifford algebras, one can always turn a geometric analogue of an HRR into a form of matrix distributed representation. In typical applications the resulting matrices are sparse, so that the matrix representation is less efficient than the representation directly employing the rules of geometric algebra. A yet more efficient procedure is based on ‘projected products’, a hierarchy of geometrically meaningful n-tuple multiplication rules obtained by combining geometric products with projections on relevant multivector subspaces. In terms of dimensionality the geometric analogues of HRRs are in between holographic and tensor-product representations.     

Attachment‐style differences in the appraisal of the attachment figure

The present study investigated the distinctive effects of global and specific attachment styles on the processing of attachment‐figure cues, focusing specifically on the role of cognitive inhibition. We manipulated the temporal accessibility of specific attachment styles and measured automatic inhibitory processes using a negative affective priming (NAP) task presenting positive and negative words. We also measured one's explicit attitude towards the attachment figure. Results showed that specific, but not global, attachment styles influenced the processing of attachment‐figure cues. We also found that participants primed with a secure attachment style showed a better inhibition of negative traits than those primed with an insecure style. At the explicit level, the anxious attachment types showed a more negative evaluation of their attachment figure than primed secures. Copyright © 2010 John Wiley & Sons, Ltd.     

Understanding Workaholics' Motivations: A Self‐Determination Perspective

In order to explain the diverging well‐being outcomes of workaholism, this study aimed to examine the motivational orientations that may fuel the two main components of workaholism (i.e. working excessively and working compulsively). Drawings on Self‐Determination Theory, both autonomous and controlled motivation were suggested to drive excessive work, which therefore was expected to relate positively to both well‐being (i.e. vigor) and ill‐health (i.e. exhaustion). Compulsive work, in contrast, was hypothesised to originate exclusively out of controlled motivation and therefore to only associate positively with ill‐being. Structural equation modeling in a heterogeneous sample of Belgian white‐collar workers (N= 370) confirmed that autonomous motivation associated positively with excessive work, which then related positively to vigor. Controlled motivation correlated positively with compulsive work, which therefore related positively with exhaustion. The hypothesised path from controlled motivation to exhaustion through excessive work was not corroborated. In general, the findings suggest that primarily compulsive work yields associations with ill‐being, since it may stem from a qualitatively inferior type of motivation.     

Cerebellar-induced apraxic agraphia: a review and three new cases

Apraxic agraphia is a writing disorder due to a loss or lack of access to motor engrams that program the movements necessary to produce letters. Clinical and functional neuroimaging studies have demonstrated that the neural network responsible for writing includes the superior parietal region and the dorsolateral and medial premotor cortex. Recent studies of two cases with atypical lesion localisations in the left thalamus and the right cerebellum support the hypothesis that the written language network is larger than previously assumed. The aim of this study is twofold: (1) to provide a survey of cases of apraxic agraphia published between 1973 and June 2010, and (2) to provide further evidence for a role of the cerebellum in writing via three additional cases who presented with apraxic agraphia after ischemic damage in the cerebellum. Functional neuroimaging studies by means of brain perfusion SPECT showed perfusional deficits in the anatomoclinically suspected supratentorial areas, subserving language dynamics, syntax, naming, writing and executive functioning.     

Attention for emotional facial expressions in dysphoria: an eye-movement registration study

Former research demonstrated that depression is associated with dysfunctional attentional processing of emotional information. Most studies examined this bias by registration of response latencies. The present study employed an ecologically valid measurement of attentive processing, using eye-movement registration. Dysphoric and non-dysphoric participants viewed slides presenting sad, angry, happy and neutral facial expressions. For each type of expression, three components of visual attention were analysed: the relative fixation frequency, fixation time and glance duration. Attentional biases were also investigated for inverted facial expressions to ensure that they were not related to eye-catching facial features. Results indicated that non-dysphoric individuals were characterised by longer fixating and dwelling on happy faces. Dysphoric individuals demonstrated a longer dwelling on sad and neutral faces. These results were not found for inverted facial expressions. The present findings are in line with the assumption that depression is associated with a prolonged attentional elaboration on negative information.     

Justified ethicality: Observing desired counterfactuals modifies ethical perceptions and behavior

Employing a die-under-cup paradigm, we study the extent to which people lie when it is transparently clear they cannot be caught. We asked participants to report the outcome of a private die roll and gain money according to their reports. Results suggest that the degree of lying depends on the extent to which self-justifications are available. Specifically, when people are allowed to roll the die three times to ensure its legitimacy, but only the first roll is supposed to “count,” we find evidence that the highest outcome of the three rolls is reported. Eliminating the ability to observe more than one roll reduces lying. Additional results suggest that observing desired counterfactuals, in the form of additional rolls not meant to determine pay, attenuates the degree to which people perceive lies as unethical. People seem to derive value from self-justifications allowing them to lie for money while feeling honest.     

Frames of reference and cooperative social decision-making

Cooperative decision-making was studied as a function of the decision-makers' own, and the interdependent other party's gain or loss frame. As expected, results showed that (a) an own gain frame produced less cognitive activity than an own loss frame and (b) other's loss frame caused more cooperation than other's gain frame, but only in case of an own gain frame.     

Dynamic factor analysis of nonstationary multivariate time series

A dynamic factor model is proposed for the analysis of multivariate nonstationary time series in the time domain. The nonstationarity in the series is represented by a linear time dependent mean function. This mild form of nonstationarity is often relevant in analyzing socio-economic time series met in practice. Through the use of an extended version of Molenaar's stationary dynamic factor analysis method, the effect of nonstationarity on the latent factor series is incorporated in the dynamic nonstationary factor model (DNFM). It is shown that the estimation of the unknown parameters in this model can be easily carried out by reformulating the DNFM as a covariance structure model and adopting the ML algorithm proposed by Jöreskog. Furthermore, an empirical example is given to demonstrate the usefulness of the proposed DNFM and the analysis.     

The boston bio-bang: The emergence of a “Regional system of innovation”

In this article we will describe the emergence of a great number of small, regionally concentrated, innovative biotech companies. We see these organizations as “hosts” of concepts and ideas, greatly influencing their spreading over the sector. We have chosen an evolutionary perspective following individual companies in their struggle for survival, describing it as “obtaining food” and “fooling predators.” This struggle gives insight in the behavior of the biotech companies and related institutions as a “system of innovation.” One of our findings is that the variety of biotech companies is conditioned by their selection environment, but that this selection environment allows great variety and even encourage variety by keeping the companies small. Haiko Van der Voort is a research associate who lectures and publishes in a wide range of issues including precess management and system innovations. Martin De Jong is associate professor of public management.     

Imposing structure on a Corsi-type task: evidence for hierarchical organisation based on spatial proximity in serial-spatial memory

Structure was imposed on a tapping task by requiring participants to reproduce sequences of responses to icons organised in spatial clusters. A first experiment featured sequences either segregated or not segregated by clusters. Accuracy was higher for sequences segregated by clusters. Moreover, inter-response times were longer at cluster boundaries than within cluster boundaries. To rule out possible confounding effects of movement length, this temporal pattern was replicated in a second experiment requiring a single response indicating the next sequential step, following the presentation of a portion of a previously practised sequence. These results suggest that sequence reproduction can be sustained by a hierarchical representation based on spatial proximity and provide a first indication of the role of spatial structure in serial-spatial memory.