Asymptotic log-linear analysis: some cautions concerning sparse frequency tables

Traditional asymptotic probability values resulting from log-linear analyses of sparse frequency tables are often much too large. Asymptotic probability values for chi-squared and likelihood-ratio statistics are compared to nonasymptotic and exact probability values for selected log-linear models. The asymptotic probability values are all too often substantially larger than the exact probability values for the analysis of sparse frequency tables. An exact nondirectional permutation method is presented to analyze combined independent multinomial distributions. Exact nondirectional permutation methods to analyze hypergeometric distributions associated with r-way frequency tables are confined to r = 2.     

Using the Internet to investigate consumer choice spaces

Traditional investigations of consumer choice processes include a matrix of alternatives described by attributes. The researcher-createdmatrix presents a product option space for the participant. In this article, we propose an alternative methodological approach to consumer choice processes. Specifically, we investigate choice processes when a participant creates his/her own product space. We describe a Web-based program and methodology used to collect data for three customizable products. Empirical results indicate that consumers are willing and able to make choices from their own product space. This research provides a new avenue for exploring choice processes.     

A FORTRAN program for computing the exact variance of weighted kappa

An algorithm and associated FORTRAN program are provided for the exact variance of weighted kappa. Program VARKAP provides the weighted kappa test statistic, the exact variance of weighted kappa, a Z score, one-sided lower- and upper-tail N(0,1) probability values, and the two-tail N(0,1) probability value.     

The prospective relation between dimensions of anxiety and the initiation of adolescent alcohol use

Examined the relation between early anxiety symptomatology (generalized and separation) and initiation of alcohol use 4 years later in an epidemiological sample of 936 children (45% girls), assessed at ages 9, 11, and 13, while controlling for the effects of depression. Although earlier overall anxiety symptomatology was unrelated to later onset of drinking, children with early symptoms of generalized anxiety were found to be at increased risk for initiation of alcohol use, whereas children with early symptoms of separation anxiety were at decreased risk. The magnitude of these relations was equally strong for boys and girls. In addition, early depressive symptomatology was associated with increased risk for initiation of alcohol use in adolescence. Results indicate that it is important to consider specific dimensions of anxiety symptomatology when attempting to identify those individuals at risk for early initiation of alcohol use.     

Testing two theories of conceptual combination: alignment versus diagnosticity in the comprehension and production of combined concepts

People often interpret novel noun-noun combinations by transferring a property from one constituent concept of the combination to the other. Two theories make different predictions about these "property" interpretations. Dual-process theory predicts that properties transferred will be alignable differences of the concepts being combined. Constraint theory predicts that properties transferred will be diagnostic properties of the concepts in which they originate. An experimental study tested these contrasting predictions in interpretation comprehension and interpretation production tasks. The results showed that participants reliably preferred diagnostic property interpretations, whether alignable or nonalignable, in both tasks. There was no reliable preference for alignable interpretations in either task. This confirms constraint theory's predictions about property interpretations and goes against the predictions of dual-process theory.     

Age-based discrimination of rival males in western bluebirds

Adaptive social behavior frequently involves discriminating between classes of individuals such as relatives versus non-relatives, older versus younger individuals, or individuals of different status. In the absence of spatial cues, this discrimination may be based on signals that correlate with fitness-related traits (e.g., older or high-status males may sing higher performance songs) or with identity, for example, when receivers distinguish and classify signalers based on their unique signal structure. Here, we examine vocal age-based discrimination in western bluebirds (Sialia mexicana), a North American songbird in which older males have a significant advantage in obtaining extra-pair fertilizations, and therefore pose a significantly higher threat to paternity than younger males. We asked whether western bluebird males showed a higher response to playback of songs of older males compared to younger males relative to their own age. We prepared song stimuli by removing three potential signals of age that have been identified as important in other species: (1) note consistency (which was achieved by playing a single instance of each note repeatedly), (2) note repertoire size, and (3) singing rate (the latter two were equalized across conditions). Even in the absence of these potential signals of age, young males responded more strongly to playback of older males’ songs than to young males’ songs, suggesting that they are able to discriminate between age classes relative to the threat they pose. Further research is required to determine whether this discrimination is based on individual recognition or signal features that are correlated with age.