What determines auditory similarity? The effect of stimulus group and methodology.

Two experiments on the internal representation of auditory stimuli compared the pairwise and grouping methodologies as means of deriving similarity judgements. A total of 45 undergraduate students participated in each experiment, judging the similarity of short auditory stimuli, using one of the methodologies. The experiments support and extend Bonebright's (1996) findings, using a further 60 stimuli. Results from both methodologies highlight the importance of category information and acoustic features, such as root mean square (RMS) power and pitch, in similarity judgements. Results showed that the grouping task is a viable alternative to the pairwise task with N > 20 sounds whilst highlighting subtle differences, such as cluster tightness, between the different task results. The grouping task is more likely to yield category information as underlying similarity judgements.

Designing trend-monitoring sounds for helicopters: methodological issues and an application.

This article explores methodological issues in sonification and sound design arising from the design of helicopter monitoring sounds. Six monitoring sounds (each with 5 levels) were tested for similarity and meaning with 3 different techniques: hierarchical cluster analysis, linkage analysis, and multidimensional scaling. In Experiment 1, similarity ratings for the top and bottom levels of the sounds were obtained. In Experiments 2 and 3, the stimuli were rated along adjectives relevant to their application. The different sound groupings that resulted from the different clustering techniques are discussed, as is the potentially contradictory relationship between acoustic dimensions and adjectival descriptors. Generally, the results validate the design of the sounds and show that increases in stimulus value are more salient than are decreases.

Linguistic and location effects in compliance with pesticide warning labels for amateur and professional users.

Three studies explored amateur and professional users' compliance with pesticide warning labels. Professionals were classified as people working in a profession in which the use of pesticides is a necessary part of their job. Amateurs used pesticides only in their leisure time. The first study showed that the wording used affected perception of the appropriateness of hazard statements, one of the most effective variations being the use of the personal pronoun (statements beginning "You should..."). The location of warning information was also found to affect actual compliance: Compliance increased when warning information was presented in the directions for use section. A supplemental directive increased compliance only for professional users. In a final study, "best-case" and "worst-case" linguistic variations were combined with best-case and worst-case locations for safety information. Instruction statements using the personal pronoun and presented in the directions for use section resulted in the highest levels of compliance. The differences in compliance between amateur and professional users are interpreted within the framework of Rasmussen's (1986) distinction among skill-, rule-, and knowledge-based behavior. Actual or potential applications of this research include the design of warning labels and safety information.