Effects of perceptual complexity on older and younger adults’ target acquisition performance

The present study evaluated the effects of the three perceptual complexity factors: number of elements, colour variety, and graphical background clutter level, on older and younger adults’ target acquisition time within a computer display. Experiment 1 manipulated the total number of icons, Experiment 2 manipulated the variety of icon colours, and Experiment 3 manipulated the clutter level of the graphical background on the display. In each experiment, 12 older and 12 younger adults were asked to move a cursor to a target icon on the display as quickly and accurately as possible. Target size and distance to the cursor were also manipulated to yield different difficulties of targets. Target acquisition time and Fitts’ law slope were analysed. Results showed that target acquisition time increased for more difficult targets under all the three complexity factors. The amount of increase was more evident for the factors of colour variety and graphical background clutter than for the number of icons. Older participants performed more slowly than younger participants did, particularly for more difficult targets. However, the impact of the three complexity factors on acquisition time appeared to be comparable for both age groups. The results suggest that implementations of colour varieties and graphical backgrounds on interfaces should be restricted, especially when icon acquisition is a common activity involved in interacting with an interface.     

A Meta-Analysis of Primate Hand Preferences, Particularly for Reaching.

P. F. MacNeilage, M. G. Studdert-Kennedy, and B. Lindblom (1987) proposed a progression for handedness in primates that was supposed to account for the evolution of a right bias in human handedness. To test this proposal, the authors performed meta-analyses on 62 studies that provided individual data (representing 31 species: 9 prosimians, 6 New World monkeys, 10 Old World monkeys, 2 lesser apes, and 4 greater apes), of the 118 studies of primate handedness published since 1987. Although evidence of a population-level left-handed bias for prosimians and Old World monkeys supports P. F. MacNeilage et al., the data from apes, New World monkeys, and individual species of prosimians and New World monkeys do not. Something other than primate handedness may have been the evolutionary precursor of the right bias in hand-use distribution among hominids. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The application of Fourier deconvolution to reaction time data: A cautionary note.

The Fourier transform method in conjunction with frequency domain smoothing techniques has been suggested as a powerful tool for examining components in a serial, additive reaction time model (P. L. Smith; see record 1991-06460-001). Robustness and sensitivity to violations of the assumptions of serial model of this method are evaluated. When an incorrect distribution was used in recovering an unobserved component, results gave no information to show that an incorrect distribution was used, and the results were just as interpretable as those obtained using the correct distribution. These results demonstrate that the assumptions underlying the method cannot be assessed by the result of deconvolution, and the method cannot show that the purported component is actually from the serial combination. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Computing confidence intervals of item fit statistics in the family of Rasch models using the bootstrap method

The item infit and outfit mean square errors (MSE) and their t-transformed statistics are widely used to screen poorly fitting items. The t-transformed statistics, however, do not follow the standard normal distribution so that hypothesis testing of item fit based on the conventional critical values is likely to be inaccurate (Wang and Chen, 2005). The MSE statistics are effect-size measures of misfit and have an expected value of unity when the data fit the model's expectation. Unfortunately, most computer programs for item response analysis do not report confidence intervals of the item infit and outfit MSE, mainly because their sampling distributions are analytically intractable. Hence, the user is left without interval estimates of the magnitudes of misfit. In this study, we developed a FORTRAN 90 computer program in conjunction with the commercial program WINSTEPS (Linacre, 2001) that yields confidence intervals of the item infit and outfit MSE using the bootstrap method. The utility of the program is demonstrated through three illustrations of simulated data sets.     

A GENERALIZED FRACTIONALLY INTEGRATED AUTOREGRESSIVE MOVING-AVERAGE PROCESS

Abstract. This paper considers the long memory Gegenbauer autoregressive movingaverage (GARMA) process that generalizes the fractionally integrated ARMA (ARFIMA) process to allow for hyperbolic and sinusoidal decay in autocorrelations. We propose the conditional sum of squares method for estimation (which is asymptotically equivalent to the maximum likelihood estimation) and develop the asymptotic theory. Many results are in sharp contrast to those of the ARFIMA model. Simulations are conducted to assess the performance of the proposed estimators in small sample applications. Two applications to the sunspot data and the US inflation rates based on the wholesale price index are provided.     

Effect of deposition sequence of platinum and ruthenium particles into nanofibrous network of polyaniline–poly(styrene sulfonic acid) on electrocatalytic oxidation of methanol

This study reports on the preparation of Pt- and Ru-based electrocatalysts through electrodeposition of Pt and Ru particles into the nanofibrous network of polyaniline (PANI)–poly(styrene sulfonic acid) (PSS). The sequence of electrodeposition of Pt and Ru particles was changed and the electrocatalysts, PANI–PSS–Pt–Ru and PANI–PSS–Ru–Pt, were obtained. Scanning electron microscopy (SEM), X-ray photoelectron microscopy (XPS), and cyclic voltammetry (CV) were employed to investigate the morphology, structural and electrochemical properties of the electrocatalysts, PANI–PSS–Pt–Ru and PANI–PSS–Ru–Pt. The distribution of Pt and Ru particles into PANI–PSS matrix was analyzed by the Auger depth profiles. The electrochemical behavior PANI–PSS–Pt–Ru and PANI–PSS–Ru –Pt and the electrocatalytic behavior toward oxidation of methanol were evaluated by cyclic voltammetry. PANI–PSS–Ru–Pt exhibited a superior electrocatalytic performance for methanol oxidation as compared to PANI–PSS–Pt–Ru.