Lotus 1-2-3 simulation of frequency encoding on the basilar membrane

A spreadsheet simulation was designed to describe frequency encoding on the basilar membrane according to the place theory (Greenwood, 1961). For any given frequency, the simulation displayed the location of maximum amplitude on the basilar membrane and the relevant critical bandwidth. The authors found a very high correlation between data given by the simulation and data from empirical research. The high correlation indicates the validity of the place theory of frequency encoding and the usefulness of this simulation for future research purposes.     

Matrix manipulation and interpretation of data related to AIDS transmission

This research describes how a currently available spreadsheet program can be set up to analyze sociographic data. An algorithm developed by Jamrich (1960) is presented, along with both the mathematical and the spreadsheet equations. An example of the application of the algorithm and equations to AIDS transmission data is presented.     

Hemispheric differences in the interference among components of compound gratings

The relationship between local/global and high/low spatial-frequency processing in hemispheric asymmetries was explored. Subjects were required to judge the orientation of a high- or low-spatial-frequency component of a compound grating presented in the left visual field (LVF) or right visual field (RVF). In Experiment 1, attention was focused on one or the other component. A signal detection analysis indicated that sensitivity (d′) to the high-spatial-frequency target was reduced more by the presence of the low-spatial-frequency component when both were presented in the LVF rather than in the RVF. In Experiment 2, subjects determined whether a target orientation was present, independent of spatial frequency at only a single level (i.e., at the high- or low-spatial-frequency level), as opposed to both or neither level. An RVF/LH (left hemisphere) advantage was found when the decision was based on the orientation of the high-frequency component. The asymmetrical influence of visual field of presentation and spatial frequency upon sensitivity is discussed in terms of hemispheric differences in the magnitude of inhibition between spatial-frequency channels and in the role of transient channel activity to capture and direct higher order attentional processes.     

Predictive testing and oncogenes

Case vignette: sharing unanticipated genetic information. The Questor family has experienced an unusual number of malignancies in the past two generations and has been advised by an oncologist that the p53 oncogene known as Li-Fraumeni Syndrome may be present in the family genome. The option of predictive genetic testing has been raised and several branches of the family have chosen to undergo screening to determine whether they are at risk for cancer because of the gene. Roger and Liz Questor have arranged for screening of themselves and their three children, ages 12, 10, and 7. The couple has, by all appearances, been happily married for 14 years. None of the family members are found to carry the oncogene; however, the geneticist conducting the analyses has made an interesting incidental discovery. The 10-year-old child is not the biological progeny of Roger Questor. Although the 12- and 7-year-olds are clearly the biological children of the couple, it is evident that the 10-year-old born to Liz Questor was fathered by a person other than Roger. What are the ethical obligations of the geneticist with respect to any sharing or disclosure of the information that has been discovered incidentally? What course of action, if any, do you recommend?     

Coping with peer stressors and associated dysphoria: Acculturation differences among Chinese-American children

The purpose of this study was to explore the role of acculturation in coping with stress among 264 Chinese-American children. The results confirmed that the subjects used a variety of coping strategies including diversion, suppression, problem solving, minimization, and retaliation and that certain coping strategies influenced the dysphoria experienced as a result of peer stress. High acculturated children used retaliation significantly more often than their low acculturated counterparts and retaliation was found to be associated with less dysphoria for the high acculturated group. In contrast, low acculturated children who utilized suppression tended to report less dysphoria. Contrary to the hypothesis that general self worth would reduce the relationship between peer stressors and dysphoria, it had no bearing on the association for either acculturated group. The hypothesis that greater perceived social competence would lessen the association between peer stressors and dysphoria also failed to be supported by the data. In fact, for the high acculturation group higher social competence was actually associated with more reported dysphoria. In general, the results suggested that the adaptiveness of particular coping strategies may be influenced by acculturation level and that social competence plays a complicated role in the stress and coping process. Implications for counsellors are discussed.     

Hinton diagrams: Viewing connection strengths in neural networks

A graphical analysis similar to that used by Hinton and Shallice (1991) was applied to the hair cells of a simulated auditory transducer. The graphical analysis made it apparent that there were hair cells that responded to a narrow range of frequencies, as would be predicted by the tonotopic organization of the real physiology. In short, this study demonstrates the efficacy of using graphic techniques to examine the nature of the autopoetic organization of the hidden layer of back-propagation networks.     

Latent Structure of the Sources of Mathematics Self-Efficacy

General social cognitive theory and its career-specific elaborations posit four primary sources through which self-efficacy beliefs are acquired and modified: personal performance accomplishments, vicarious learning, social persuasion, and physiological states and reactions. We present two studies exploring the dimensionality of these sources within the context of career-relevant mathematics activities. In Study 1, 295 college students completed measures of the source variables. Testing two- through five-factor models, we found strongest support for a four-factor latent structure of the efficacy sources. In Study 2, involving 481 high school students, a five-factor model fit the data well. We also found evidence of a higher order factor structure in both samples. Several directions for further research on the sources of efficacy information are considered, along with implications for career and academic interventions.     

Estimating the polyserial correlation coefficient

We develop simple noniterative estimators of the polyserial correlation coefficient. A general relationship between the polyserial correlation and the point polyserial correlation is exploited to give extensions of Pearson's, Brogden's, and Lord's biserial estimators to the multicategory setting. The small sample and asmptotic properties of these estimators are studied in some detail. A comparison with maximum likelihood estimates shows that Lord's polyserial estimator is fairly efficient across three probability models.The authors would like to thank the referees for suggestions that improved the presentation of the paper.