The detection of feature singletons defined in two dimensions is based on salience summation, rather than on serial exhaustive or interactive race architectures

Influential models of visual search assume that dimension-specific feature contrast signals are summed into a master saliency map in a coactive fashion. The main source of evidence for coactivation models, and against parallel race models, is violations of the race model inequality (RMI; Miller, 1982) by redundantly defined singleton feature targets. However, RMI violations do not rule out serial exhaustive (Townsend & Nozawa, 1997) or interactive race (Mordkoff & Yantis, 1991) architectures. These alternatives were tested in two experiments. In Experiment 1, we used a double-factorial design with singleton targets defined in two dimensions and at two levels of intensity, to distinguish between serial versus parallel models and self-terminating versus exhaustive stopping rules. In Experiment 2, we manipulated contingency benefits that are expected to affect the magnitude of redundancy gains and/or RMI violations on the assumption of an interactive race. The results of both experiments revealed redundancy gains as well as violations of the RMI, but the data pattern excluded serial-exhaustive and interactive race models as possible explanations for RMI violations. This result supports saliency summation (coactivation) models of search for singleton feature targets.     

Social Comparison and Information Transmission in the Work Context

In the workplace, people can experience various types of failure and frustrations resulting in spontaneous social comparisons with other colleagues who are more (upward comparison) or less (downward comparison) successful. Upward comparisons especially have been shown to increase envy toward the outperforming benchmark colleague, which could negatively affect social interaction with this colleague. In line with this, our results consistently show that upward comparisons are associated with higher levels of experienced envy, as well as with a lower transmission rate of high-quality information. By contrast, type of social comparison had no impact on the amount of transmitted low-quality, work-relevant information. Theoretical and practical implications are discussed.     

Large-Scale Assessment of Change in Student Achievement: Dutch Primary School Students’ Results on Written Division in 1997 and 2004 as an Example

This article discusses large-scale assessment of change in student achievement and takes the study by Hickendorff, Heiser, Van Putten, and Verhelst (2009) as an example. This study compared the achievement of students in the Netherlands in 1997 and 2004 on written division problems. Based on this comparison, they claim that there is a performance decline in this subdomain of mathematics, and that there is a move from applying the digit-based long division algorithm to a less accurate way of working without writing down anything. In our discussion of this study, we address methodological challenges that come in when investigating long-term trends in student achievements, such as the need for adequate operationalizations, the influence of the time of measurement and the necessity of the comparability of assessments, the effect of the assessment format, and the importance of inclusion relevant covariates in item response models. All these issues matter when assessing change in student achievement.     

Alcohol consumption and handwriting: A kinematic analysis

Cerebellar dysfunction is associated with deficits in the control of movement extent, as well as changes in the amplitude and relative amounts of acceleration and deceleration and action tremor. The present study sought to identify whether cerebellar symptoms occur in the handwriting of intoxicated individuals. Twenty participants in two sub-groups (alcohol dependent and non-alcohol dependent) were asked to write four cursive letter ‘l’s on a Wacom SD420 graphics tablet before and after consumption of a dose of vodka and orange producing a peak blood alcohol concentration of 0.048%. There was a relationship between blood alcohol concentration and stroke length. Kinematic analysis of handwriting indicated increases in the relative proportions of time spent in acceleration and increases in spectral power around 4 Hz. It was found that alcohol intoxication causes symptoms of cerebellar dysfunction, and that alcohol dependent individuals had less ballistic handwriting compared to non-alcohol dependent participants.     

What do eye movements reveal about the role of memory in visual search?

Horowitz and Wolfe (1998, 2003) have challenged the view that serial visual search involves memory processes that keep track of already inspected locations. The present study used a search paradigm similar to Horowitz and Wolfe's (1998), comparing a standard static search condition with a dynamic condition in which display elements changed locations randomly every 111 ms. In addition to measuring search reaction times, observers' eye movements were recorded. For target-present trials, the search rates were near-identical in the two search conditions, replicating Horowitz and Wolfe's findings. However, the number of fixations and saccade amplitude were larger in the static than in the dynamic condition, whereas fixation duration and the latency of the first saccade were longer in the dynamic condition. These results indicate that an active, memory-guided search strategy was adopted in the static condition, and a passive “sit-and-wait” strategy in the dynamic condition.     

Variability, covariation, and invariance with respect to coordinate systems in motor control: reply to Smeets and Louw (2007)

In their comment on the tolerance-noise covariation (TNC) method for decomposing variability by H. Müller and D. Sternad (2003, 2004b), J. B. J. Smeets and S. Louw show that covariation (C), as defined within the TNC method, is not invariant with respect to coordinate transformations and contend that it is, therefore, meaningless. Although the observation is correct, their interpretation is misleading in the following ways: (a) They equate covariation C with the known statistical quantity covariance and noise (N) with standard deviations. The two quantities C and N are conceptually different statistical measures. (b) Dependency on the reference frame is not only a feature of C but of all 3 components. However, such dependency is ubiquitous in motor control. (c) As the frame of reference in biological systems is poorly understood, the TNC method may afford evaluation of different coordinates for control.     

Against a Minimalist Reading of Bell's Theorem: Lessons from Fine

Since the validity of Bell's inequalities implies the existence of joint probabilities for non-commuting observables, there is no universal consensus as to what the violation of these inequalities signifies. While the majority view is that the violation teaches us an important lesson about the possibility of explanations, if not about metaphysical issues, there is also a minimalist position claiming that the violation is to be expected from simple facts about probability theory. This minimalist position is backed by theorems due to A. Fine and I. Pitowsky.Our paper shows that the minimalist position cannot be sustained. To this end,we give a formally rigorous interpretation of joint probabilities in thecombined modal and spatiotemporal framework of `stochastic outcomes inbranching space-time' (SOBST) (Kowalski and Placek, 1999; Placek, 2000). We show in this framework that the claim that there can be no joint probabilities fornon-commuting observables is incorrect. The lesson from Fine's theorem is notthat Bell's inequalities will be violated anyhow, but that an adequate modelfor the Bell/Aspect experiment must not define global joint probabilities. Thus we investigate the class of stochastic hidden variable models, whichprima facie do not define such joint probabilities. The reasonwhy these models fail supports the majority view: Bell's inequalities are notjust a mathematical artifact.     

Computer tomography identification of carriers of Duchenne progressive muscular dystrophy

Comparison of findings obtained by computed tomography of muscles of possible carriers and normal subjects demonstrated that structural changes existed in 31 out of 74 women; the certainty of the information obtained became greater with increasing age. Six of the seven genealogically definite carriers were detected by computed tomography. The present results show that the use of computed tomography is promising for future carrier diagnosis.     

Computer tomography studies in myotonic dystrophies

Besides clinical symptoms, progress and electromyography the computer tomography is a possibility for improvement the diagnostic of myotone dystrophy. Even small changes in muscle structure are detectable and especially m. soleus exhibits early and pronounced alterations. By means of density distribution pattern an improved characterization of the disease is possible. Additional informations are obtained by cerebralcomputertomography. Hints for atrophy of brain tissue are expectable at all patients with myotone dystrophy. According to the presented findings the computer tomography enlarges the diagnostic possibilities at myotone dystrophy.