Diffusion versus linear ballistic accumulation: different models but the same conclusions about psychological processes?

Quantitative models for response time and accuracy are increasingly used as tools to draw conclusions about psychological processes. Here we investigate the extent to which these substantive conclusions depend on whether researchers use the Ratcliff diffusion model or the Linear Ballistic Accumulator model. Simulations show that the models agree on the effects of changes in the rate of information accumulation and changes in non-decision time, but that they disagree on the effects of changes in response caution. In fits to empirical data, however, the models tend to agree closely on the effects of an experimental manipulation of response caution. We discuss the implications of these conflicting results, concluding that real manipulations of caution map closely, but not perfectly to response caution in either model. Importantly, we conclude that inferences about psychological processes made from real data are unlikely to depend on the model that is used

Legacy Vehicle Fuel System Testing with Intermediate Ethanol Blends

The effects of E10 and E17 on legacy fuel system components from three common mid-1990s vintage vehicle models (Ford, GM, and Toyota) were studied. The fuel systems comprised a fuel sending unit with pump, a fuel rail and integrated pressure regulator, and the fuel injectors. The fuel system components were characterized and then installed and tested in sample aging test rigs to simulate the exposure and operation of the fuel system components in an operating vehicle. The fuel injectors were cycled with varying pulse widths during pump operation. Operational performance, such as fuel flow and pressure, was monitored during the aging tests. Both of the Toyota fuel pumps demonstrated some degradation in performance during testing. Six injectors were tested in each aging rig. The Ford and GM injectors showed little change over the aging tests. Overall, based on the results of both the fuel pump testing and the fuel injector testing, no major failures were observed that could be attributed to E17 exposure. The unknown fuel component histories add a large uncertainty to the aging tests. Acquiring fuel system components from operational legacy vehicles would reduce the uncertainty

Magnetic form factor of SrFe2_2As2_2

Neutron diffraction measurements have been carried out to investigate the magnetic form factor of the parent SrFe2As2 system of the iron-based superconductors. The general feature is that the form factor is approximately isotropic in wave vector, indicating that multiple d-orbitals of the iron atoms are occupied as expected based on band theory. Inversion of the diffraction data suggests that there is some elongation of the spin density toward the As atoms. We have also extended the diffraction measurements to investigate a possible jump in the c-axis lattice parameter at the structural phase transition, but find no detectable change within the experimental uncertainties

SuperB: a linear high-luminosity B Factory

This paper is based on the outcome of the activity that has taken place during the recent workshop on "SuperB in Italy" held in Frascati on November 11-12, 2005. The workshop was opened by a theoretical introduction of Marco Ciuchini and was structured in two working groups. One focused on the machine and the other on the detector and experimental issues. The present status on CP is mainly based on the results achieved by BaBar and Belle. Estabilishment of the indirect CP violation in B sector in 2001 and of the direct CP violation in 2004 thanks to the success of PEP-II and KEKB e+e- asymmetric B Factories operating at the center of mass energy corresponding to the mass of the Y(4s). With the two B Factories taking data, the Unitarity Triangle is now beginning to be overconstrained by improving the measurements of the sides and now also of the angles alpha, and gamma. We are also in presence of the very intriguing results about the measurements of sin(2 beta) in the time dependent analysis of decay channels via penguin loops, where b --> s sbar s and b --> s dbar d. Tau physics, in particular LFV search, as well as charm and ISR physics are important parts of the scientific program of a SuperB Factory. The physics case together with possible scenarios for the high luminosity SuperB Factory based on the concepts of the Linear Collider and the related experimental issues are discussed.Comment: 22 pages, 22 figures, INFN Roadmap Repor

Testing theories of post-error slowing

People tend to slow down after they make an error. This phenomenon, generally referred to as post-error slowing, has been hypothesized to reflect perceptual distraction, time wasted on irrelevant processes, an a priori bias against the response made in error, increased variability in a priori bias, or an increase in response caution. Although the response caution interpretation has dominated the empirical literature, little research has attempted to test this interpretation in the context of a formal process model. Here, we used the drift diffusion model to isolate and identify the psychological processes responsible for post-error slowing. In a very large lexical decision data set, we found that post-error slowing was associated with an increase in response caution and—to a lesser extent—a change in response bias. In the present data set, we found no evidence that post-error slowing is caused by perceptual distraction or time wasted on irrelevant processes. These results support a response-monitoring account of post-error slowing

On the interpretation of removable interactions: A survey of the field 33 years after Loftus

In a classic 1978 Memory &Cognition article, Geoff Loftus explained why noncrossover interactions are removable. These removable interactions are tied to the scale of measurement for the dependent variable and therefore do not allow unambiguous conclusions about latent psychological processes. In the present article, we present concrete examples of how this insight helps prevent experimental psychologists from drawing incorrect conclusions about the effects of forgetting and aging. In addition, we extend the Loftus classification scheme for interactions to include those on the cusp between removable and nonremovable. Finally, we use various methods (i.e., a study of citation histories, a questionnaire for psychology students and faculty members, an analysis of statistical textbooks, and a review of articles published in the 2008 issue of Psychology andAging) to show that experimental psychologists have remained generally unaware of the concept of removable interactions. We conclude that there is more to interactions in a 2 × 2 design than meets the eye