ThurCatD: A tool for analyzing ratings on an ordinal category scale

An algorithm for analyzing ordinal scaling results is described. Frequency data on ordinal categories are modeled for unidimensional psychological attributes according to Thurstone’s judgment scaling model. The algorithm applies maximum likelihood estimation of model parameters. The Cramér-Rao bounds of the standard errors of the estimated parameters are calculated, and a stress measure and a goodness-of-fit measure are supplied.     

DifScal: A tool for analyzing difference ratings on an ordinal category scale

An algorithm for analyzing difference scaling results is described. Frequency data on ordered categories that represent perceived differences for a unidimensional psychological attribute are modeled according to Thurstone’s judgment scaling model. The algorithm applies the gradient method for the maximum likelihood estimation of the model parameters. Two ways to calculate the start configuration for the model parameters are elaborated. The algorithm also provides asymptotic values for the standard errors of the estimates and three measures for the goodness of the model fit. An additional feature of DifScal is that it is suited to analyze incomplete data.     

Intrapersonal and social comparison determinants of happiness: a range-frequency analysis

Examined whether intrapersonal comparisons and social comparisons operate in similar ways to determine ratings of happiness. Events were varied to create positively and negatively skewed distributions. The events in each distribution were ascribed to either a single person or a group of people; Ss rated how happy they would feel if they experienced specific events within the distribution. Ratings for both intrapersonal and social comparisons were fit well by Parducci's (1984) range-frequency theory. Individual events received higher ratings when presented within the positively skewed context. Overall happiness, as measured by both the mean of the happiness ratings as well as direct ratings, was highest for the negatively skewed distributions. The effects of skewing were more pronounced for intrapersonal comparisons, but ratings were more closely defined by the range of experimental stimuli for social comparisons.     

The contribution of category relationships to similarity ratings.

Two experiments produced evidence that category relationships contribute to similarity ratings. In Experiment 1, participants gave similarity ratings with respect to a semantic category (VEGETABLE) and a set of exemplars, some of which were members of the category (e.g., BROCCOLI) and some of which were not (e.g., BANANA). A regression analysis was used to predict the similarity ratings in terms of numbers of common and distinctive features, as reported by other participants. Perceived similarity was greater for examplars that were members of the category, independently of feature overlap. Experiment 2 examined similarity ratings with respect to pairs of exemplars. In some cases, both exemplars were members of the same category (e.g., BROCCOLI/CUCUMBER). In other cases, one exemplar was a member of the category and the other was not (e.g., BROCCOLI/BANANA). A regression analysis was used to predict the similarity ratings in terms of numbers of common and distinctive features. Perceived similarity was greater when both exemplars were members of the same category, independently of feature overlap.     

The dimensionality of perceptual category learning: A state-trace analysis

State-trace analysis was used to investigate the effect of concurrent working memory load on perceptual category learning. Initial reanalysis of Zeithamova and Maddox (2006, Experiment 1) revealed an apparently two-dimensional state-trace plot consistent with a dual-system interpretation of category learning. However, three modified replications of the original experiment found evidence of a single resource underlying the learning of both rule-based and information integration category structures. Follow-up analyses of the Zeithamova and Maddox data, restricted to only those participants who had learned the category task and performed the concurrent working memory task adequately, revealed a one-dimensional plot consistent with a single-resource interpretation and the results of the three new experiments. The results highlight the potential of state-trace analysis in furthering our understanding of the mechanisms underlying category learning.     

A critical analysis of students' teacher ratings

Analysis of data obtained from 258 second-year undergraduate students revealed that sex differences are not associated with differences in students' teacher ratings. Significant differences in ratings were found to be associated with differences in academic performance and with differences in preference for anonymity when submitting ratings. These findings suggest that students' ratings of teaching performance suffer from significant validity problems and that such ‘performance indicators’ are likely to provide misleading information.     

Agreement of adolescent ratings with mother ratings and teacher ratings of ADHD symptom groups: A correlated trait-correlated method minus one analysis

This study examined the level of agreement of adolescent ratings with mother ratings, and adolescent ratings with teacher ratings of the inattention (IA) and hyperactivity/impulsivity (HI) symptom groups of ADHD. A total of 214 adolescents provided self-ratings of IA and HI, and their IA and HI were also rated by their mothers and teachers. The correlated trait-correlated method minus one model was applied, with adolescent ratings as the reference method, and the other two ratings as the non-reference methods. The findings indicated no additional variance in adolescent ratings for IA and HI that could not be accounted by mother ratings of IA and HI, respectively. In contrast, there was additional variance in adolescent ratings for IA and HI that could was not accounted by teacher ratings of IA and HI, respectively. The findings suggest that when diagnosing ADHD in adolescents, their reports of their own ADHD behaviors are not needed when mother reports of such behaviors are used.     

A rasch model for continuous ratings

A unidimensional latent trait model for continuous ratings is developed. This model is an extension of Andrich's rating formulation which assumes that the response process at latent thresholds is governed by the dichotomous Rasch model. Item characteristic functions and information functions are used to illustrate that the model takes ceiling and floor effects into account. Both the dichotomous Rasch model and a linear model with normally distributed error can be derived as limiting cases. The separability of the structural and incidental parameters is demonstrated and a procedure for estimating the parameters is outlined.     

Resolving syntactic category ambiguity: An eye-movement analysis

In two experiments, participants' eye movements were monitored as they read sentences containing biased syntactic category ambiguous words with either distinct (e.g., duck) or related (e.g., burn) meanings or unambiguous control words. In Experiment 1, prior context was consistent with either the dominant or subordinate interpretation of the ambiguous word. The subordinate bias effect was absent for the ambiguous words in gaze duration measures. However, effects of ambiguity did emerge in other measures for the ambiguous words preceded by context supporting the subordinate interpretation. In Experiment 2, context preceding the target words was neutral. Ambiguity effects only arose when posttarget context was consistent with the subordinate interpretation of the ambiguous words, indicating that readers initially selected the dominant interpretation. Results support immediate theories of syntactic category ambiguity resolution, but also suggest that recovery from misanalysis of syntactic category ambiguity is more difficult than for lexical-semantic ambiguity in which alternate interpretations do not cross syntactic category.     

A signal detection theory analysis of a category judgment experiment

A category-judgment experiment is the reported. Rating-scale judgments of loudness were made with five or eight intensity levels of a tone and with different frequencies of presentation of the stimuli. Obtained ROC curves for pairs of stimuli were judged to support application of signal-detection theory. However, certain common assumptions of the theory are called into question by the data. Discrimination was poorer when more categories were available. This is attributed to an increase in criterion variance with an increase in the number of criteria. The slope of the ROC curves for different stimulus pairs suggested that stimulus variance is neither constant nor does it necessarily increase with stimulus intensity It is argued that stimulus variance may depend upon the distribution of internal observations over all trials.     

Modeling: An analysis in terms of category accessibility

It is proposed that many of the releasing or disinhibiting effects caused by models can be accounted for by information-processing mechanisms, without recourse to the concept of reinforcement. More specifically, it is suggested that the process of viewing a model's behavior involves the activation of an interpretive schema. This renders the information the schema incorporates more accessible for subsequent use. If the schema incorporates (or is closely related to) behavior-specifying information, that information becomes more accessible as well, thus making it more likely to influence overt behavior. Two studies are reported that assessed the plausibility of this reasoning. In Experiment 1 subjects who had viewed an aggressive model perceived greater hostility in the behavior of an ambiguous stimulus person that they subsequently encountered than did control subjects. This finding is consistent with the assumption that the model's behavior activated a conceptual schema for use in interpretation. In Experiment 2 subjects in whom an aggressive schema had been activated under a guise displayed greater aggression in their subsequent behavior in a different context than did control subjects. This finding is consistent with the assumption that activating the conceptual schema also activated behavioral information. The discussion centers on the implications of the findings.     

Independent component analysis: an introduction

Independent component analysis (ICA) is a method for automatically identifying the underlying factors in a given data set. This rapidly evolving technique is currently finding applications in analysis of biomedical signals (e.g. ERP, EEG, fMRI, optical imaging), and in models of visual receptive fields and separation of speech signals. This article illustrates these applications, and provides an informal introduction to ICA.     

A formal analysis of ratings of physical attractiveness: Successive contrast and simultaneous assimilation

Photographs of faces were presented in a series, either singly or in pairs, for ratings of physical attractiveness. In Experiment 1, faces were presented singly, and both the range and relative frequencies of physical attractiveness (on baseline scaling) were manipulated experimentally. The same face elicited higher ratings when less attractive faces predominated in the experimental series, successive contrast. Increasing the number of available categories resulted in higher ratings but did not reduce the amount of successive contrast. Both range and skewing effects were in accordance with a range-frequency model that permits the subjective range to vary with number of categories. In Experiment 2, faces were presented in pairs. The same face now elicited lower ratings when presented simultaneously with a less attractive face, simultaneous assimilation. Successive contrast was again observed between pairs and was greater for 5- than for 101-point rating scales. A model that uses the judgments resulting from a range-frequency compromise as the stimulus values for integration within pairs provides the best account of how both contrast and assimilation occur within the same experimental session. Alternative interpretations of the observed contrast and assimilation were discussed.