Properties of and Algorithms for Fitting Three-Way Component Models with Offset Terms

Prior to a three-way component analysis of a three-way data set, it is customary to preprocess the data by centering and/or rescaling them. Harshman and Lundy (1984) considered that three-way data actually consist of a three-way model part, which in fact pertains to ratio scale measurements, as well as additive “offset” terms that turn the ratio scale measurements into interval scale measurements. They mentioned that such offset terms might be estimated by incorporating additional components in the model, but discarded this idea in favor of an approach to remove such terms from the model by means of centering. Then estimates for the three-way component model parameters are obtained by analyzing the centered data. In the present paper, the possibility of actually estimating the offset terms is taken up again. First, it is mentioned in which cases such offset terms can be estimated uniquely. Next, procedures are offered for estimating model parameters and offset parameters simultaneously, as well as successively (i.e., providing offset term estimates after the three-way model parameters have been estimated in the traditional way on the basis of the centered data). These procedures are provided for both the CANDECOMP/PARAFAC model and the Tucker3 model extended with offset terms. The successive and the simultaneous approaches for estimating model and offset parameters have been compared on the basis of simulated data. It was found that both procedures perform well when the fitted model captures at least all offset terms actually underlying the data. The simultaneous procedures performed slightly better than the successive procedures. If fewer offset terms are fitted than there are underlying the model, the results are considerably poorer, but in these cases the successive procedures performed better than the simultaneous ones. All in all, it can be concluded that the traditional approach for estimating model parameters can hardly be improved upon, and that offset terms can sufficiently well be estimated by the proposed successive approach, which is a simple extension of the traditional approach. The author is obliged to Jos M.F. ten Berge and Marieke Timmerman for helpful comments on an earlier version of this paper. The author is obliged to Iven van Mechelen for making available the data set used in Section 6.     

On growth curves and mixture models

The multilevel model of change and the latent growth model are flexible means to describe all sorts of population heterogeneity with respect to growth and development, including the presence of sub‐populations. The growth mixture model is a natural extension of these models. It comes at hand when information about sub‐populations is missing and researchers nevertheless want to retrieve developmental trajectories from sub‐populations. We argue that researchers have to make rather strong assumptions about the sub‐populations or latent trajectory classes in order to retrieve existing population differences. A simulated example is discussed, showing that a sample of repeated measures drawn from two sub‐populations easily leads to the mistaken inference of three sub‐populations, when assumptions are not met. The merits of methodological advises on this issue are discussed. It is concluded that growth mixture models should be used with understanding, and offer no free way to growth patterns in unknown sub‐populations. Copyright © 2006 John Wiley & Sons, Ltd.     

Heart work after errors: Behavioral adjustment following error commission involves cardiac effort

Posterror slowing (PES) is the observation that people respond slower on trials subsequent to error commissions than on trials subsequent to correct responses. Different accounts have been proposed to explain PES. On the one hand, it has been suggested that PES arises from an adaptive increase in cognitive control following error commission, thereby making people more cautious after making an error. On the other hand, PES has been attributed to an orienting response, indicating that attention is shifted toward the error. In the present study we tested these accounts by investigating the effects of error commission in both flanker and switch tasks on two task-evoked cardiac measures: the interbeat interval—that is, the interval between two consecutive R peaks—and the RZ interval—that is, the interval between the R peak and the Z point—as measured using electro- and impedance cardiography, respectively. These measures allowed us to measure cardiac deceleration (autonomic orienting) and cardiac effort mobilization, respectively. Our results revealed a shorter RZ interval during posterror trials, indicating increased effort mobilization following errors. In addition, we replicated earlier studies that have shown cardiac slowing during error trials. However, multilevel analyses showed that only the posterror decrease in RZ interval predicted posterror reaction times, whereas there was no positive relationship between error-related cardiac deceleration and posterror reaction times. Our results suggest that PES is related to increased cardiac effort, supporting a cognitive-control account of PES.     

Maintenance of semantic information in capacity-limited item short-term memory

We report a semantic effect in immediate free recall, which is localized at recency and is preserved under articulatory suppression but is highly reduced when recall is delayed after an intervening distractor task. These results are explained by a neurocomputational model based on a limited-capacity short-term memory (STM) store, consisting ofactivated long-term memory representations. The model makes additional predictions about serial position functions in semantically cued recall, indicating capacity limitations caused by a displacement type mechanism, which are confirmed in a second experiment. This suggests that in addition to the phonological component in verbal STM, there is an activation/ item-limited component with semantically sensitive representations.     

Language comprehension vs. language production: age effects on fMRI activation

Normal language acquisition is a process that unfolds with amazing speed primarily in the first years of life. However, the refinement of linguistic proficiency is an ongoing process, extending well into childhood and adolescence. An increase in lateralization and a more focussed productive language network have been suggested to be the neural correlates of this process. However, the processes underlying the refinement of language comprehension are less clear. Using a language comprehension (Beep Stories) and a language production (Vowel Identification) task in fMRI, we studied language representation and lateralization in 36 children, adolescents, and young adults (age 6-24 years). For the language comprehension network, we found a more focal activation with age in the bilateral superior temporal gyri. No significant increase of lateralization with age could be observed, so the neural basis of language comprehension as assessed with the Beep Stories task seems to be established in a bilateral network by late childhood. For the productive network, however, we could confirm an increase with age both in focus and lateralization. Only in the language comprehension task did verbal IQ correlate with lateralization, with higher verbal IQ being associated with more right-hemispheric involvement. In some subjects (24%), language comprehension and language production were lateralized to opposite hemispheres.     

Examination of the influence of contingency on changes in reinforcer value

This study examined how the amount of effort required to produce a reinforcer influenced subsequent preference for, and strength of, that reinforcer in 7 individuals with intellectual disabilities. Preference assessments identified four moderately preferred stimuli for each participant, and progressive-ratio (PR) analyses indexed reinforcer strength. Stimuli were then assigned to one of four conditions for 4 weeks: fixed-ratio (FR) 1 schedule, escalating FR schedule, yoked noncontingent (NCR) delivery, and restricted access. Preference assessments and PR schedules were then repeated to examine changes in selection percentages and PR break points. Selection percentages decreased for all NCR stimuli but increased for most of the restricted stimuli. There were no systematic changes in selection percentages for either of the contingent stimuli. Break points increased, on average, for all conditions, but the increase was highest for the restricted stimuli and lowest for the NCR stimuli. These results are discussed in relation to recent basic research addressing the influence of effort on stimulus value.     

Once the money is in sight: Distinctive effects of conscious and unconscious rewards on task performance

Monetary rewards facilitate performance on behavioral and cognitive tasks, even when these rewards are perceived without conscious awareness. Also, recent research suggests that consciously (vs. unconsciously) perceived rewards may prompt people to more strongly concentrate on task stimuli and details. Here we propose that the latter is sometimes dysfunctional, in that it prevents improvements in task performance. We used an Attentional Blink paradigm, in which such enhanced concentration on task stimuli is detrimental to performance. Participants were consciously (supraliminally) or unconsciously (subliminally) exposed to a high-value or low-value coin that they could earn by performing well on an Attentional Blink trial. As hypothesized, high-value rewards increased performance when they were presented subliminally, while this performance benefit vanished when high-value rewards were presented consciously. We discuss this finding in the context of recent research on unconscious goal pursuit.     

Eye tracking unconscious face-to-face confrontations: dominance motives prolong gaze to masked angry faces

In primates, dominance/submission relationships are generally automatically and nonaggressively established in face-to-face confrontations. Researchers have argued that this process involves an explicit psychological stress-manipulation mechanism: Striding with a threatening expression, while keeping direct eye contact, outstresses rivals so that they submissively avert their gaze. In contrast, researchers have proposed a reflexive and implicit modulation of face-to-face confrontation in humans, on the basis of evidence that dominant and submissive individuals exhibit vigilant and avoidant responses, respectively, to facial anger in masked emotional Stroop tasks. However, these tasks do not provide an ecologically valid index of gaze behavior. Therefore, we directly measured gaze responses to masked angry, happy, and neutral facial expressions with a saccade-latency paradigm and found that increased dominance traits predict a more prolonged gaze to (or reluctance to avert gaze from) masked anger. Furthermore, greater non-dominance-related reward sensitivity predicts more persistent gaze to masked happiness. These results strongly suggest that implicit and reflexive mechanisms underlie dominant and submissive gaze behavior in face-to-face confrontations.     

Revisiting the agentic shift: Weakening personal control increases susceptibility to social influence

What happens when people experience a reduced sense of personal control? Among the various strategies to defend against a perception of randomness, people may show an increased acceptance of external sources of control. Indeed, in one of the most classic studies in social psychology, Stanley Milgram referred to an “agentic shift”—the tendency to relinquish personal control to an external agent—to explain his dramatic obedience effects. We propose that his account is a specific manifestation of a more general phenomenon: the tendency for increased susceptibility to various forms of external social influence when perceived personal control is reduced. In a series of (lab and field) studies using a variety of perceived control manipulations, we demonstrate that a reduction in the sense of personal control increases people's vulnerability to the bystander effect, promotes obedience to authority and fosters compliance with behavioral requests. Copyright © 2012 John Wiley & Sons, Ltd.     

Romaphobia Among Serbian Adolescents: The Role of National In‐group Attitudes and Perceived Threat

This study employed the integrated threat theory to examine Serbian adolescents' attitudes towards the Roma. The sample consisted of 687 secondary school students (mean age 17), of whom 53% were females. In a survey‐based study, we assessed adolescents' national in‐group attitudes (i.e., nationalism), their feelings toward the Roma, and their perception of economic and symbolic threat. Findings suggest that perceived threat to either real resources or worldviews of the dominant group was related to more negative attitudes towards the Roma minority. Further, Romaphobia was positively related to adolescents' nationalism and this relationship was partially mediated by perceived economic and symbolic threat. The theoretical and educational implications are discussed.