Ian Dennis

Improving Auditory Warning Design: Relationship between Warning Sound Parameters and Perceived Urgency

This paper presents an experimental study of the effects of individual sound parameters on perceived (psychoacoustic) urgency. Experimental Series 1 showed that fundamental frequency, harmonic series, amplitude envelope shape, and delayed harmonics all have clear and consistent effects on perceived urgency. Experimental Series 2 showed that temporal and melodic parameters such as speed, rhythm, pitch range, and melodic structure also have clear and consistent effects on perceived urgency. The final experiment tested a set of 13 auditory warnings generated by an application of the earlier experimental findings. The urgency rank ordering of this warning set was predicted, and the correlation between the predicted and the obtained order was highly significant. The results of these experiments have a widespread application in the improvement of existing auditory warning systems and the design of new systems, where the psychoacoustic and psychological appropriateness of warnings could be enhanced.

Improving Auditory Warning Design: Quantifying and Predicting the Effects of Different Warning Parameters on Perceived Urgency

The effects of four parameters (speed, fundamental frequency, repetition units, and inharmonicity) on perceived urgency were scaled using an application of Stevenss power law. From the exponents obtained, equal units of urgency change were calculated for three parameters. The units were combined in a set of stimuli, and the order of urgency was predicted. The obtained and predicted orders of urgency were highly correlated. The results also showed that even when equalized by psychophysical techniques, some parameters contribute more to perceived urgency than do others. This may be attributable to the different types of parameters scaled or the proportion of the usable range of each parameter that represents a unit change in urgency. The implication of the work for the design and improvement of auditory warnings is discussed.

Lexical and grammatical processing of unshadowed messages: A re-examination of the Mackay effect

Mackay (1973) claimed to have provided evidence that subjects could process the grammatical structure and lexical content of nonshadowed messages. In the present study, it was found impossible to repeat Mackays findings when controls for several factors that had been ignored in Mackays study were employed. Subsequent experiments indicated that two major factors contributing to Mackays results were that he had a gap between sentences in his experiment and that the nonshadowed material came out of a background of silence. Both of these probably enabled subjects to switch attention to the nonshadowed material without disruption of shadowing performance.

Degree Performance as a Function of Age, Gender, Prior Qualifications and Discipline Studied.

Abstract The computerised records of a large university were analysed in an attempt to determine which variables served as predictors of degree performance. Age was a powerful predictor: mature students gained better degrees on average than younger students; and mature students with non‐traditional qualifications obtained the best degrees of all. Gender, year of graduation, and type of qualification were weak predictors of performance, but degree classifications were found to differ significantly across disciplines. The results are broadly consistent with previous studies, and suggest that opening access to mature students and to those with non‐traditional qualifications has not led to any diminution of standards. However, variations between disciplines and, in national statistics, between different years, suggest that steps may need to be taken to standardise degree classifications.

: Working memory, inhibitory control and the development of children's reasoning

The ability to reason independently from ones own goals or beliefs has long been recognised as a key characteristic of the development of formal operational thought. In this article we present the results of a study that examined the correlates of this ability in a group of 10-year-old children (N = 61). Participants were presented with conditional and relational reasoning items, where the content was manipulated such that the conclusion to the arguments were either congruent, neutral, or incongruent with beliefs, and either logically valid or logically invalid. Participants also received a measure of working memory capacity (the counting span task) and a measure of inhibitory control (the stop signal task). Indices of belief bias and logical reasoning on belief-based problems were predicted independently by both measures. In contrast logical reasoning on belief neutral problems was predicted by working memory alone. The findings suggest that executive functions play a key role in the development of childrens ability to decontextualise their thinking.

Problem-solving Strategies and Expertise in Engineering Design.

A study is reported which focused on the problem-solving strategies employed by expert electronics engineers pursuing a real-world task: integrated-circuit design. Verbal protocol data were analysed so as to reveal aspects of the organisation and sequencing of ongoing design activity. These analyses indicated that the designers were implementing a highly systematic solution-development strategy which deviated only a small degree from a normatively optimal top-down and breadth-first method. Although some of the observed deviation could be described as opportunistic in nature, much of it reflected the rapid depth-first exploration of tentative solution ideas. We argue that switches from a predominantly breadth-first mode of problem solving to depth-first or opportunistic modes may be an important aspect of the experts strategic knowledge about how to conduct the design process effectively when faced with difficulties, uncertainties, and design impasses.

Approaches to learning and studying in medical students: validation of a revised inventory and its relation to student characteristics and performance

Introduction  Inventories to quantify approaches to studying try to determine how students approach academic tasks. Medical curricula usually aim to promote a deep approach to studying, which is associated with academic success and which may predict desirable traits postqualification.

Proof-reading on VDUs

Abstract Two experiments are reported which compared proof-reading performance across three different modes of presentation. The results of Experiment 1 indicated that proof-reading accuracy was significantly worse on a VDU than on paper, with a photograph of the VDU display producing intermediate performance. It was also demonstrated that substitutions of visually similar errors were harder to detect than other error types. The results of Experiment 2 replicated these findings, but failed to find any difference between twin-column and single-column presentation. The findings are interpreted as indicating that character font may be a major factor in the poor performance with the VDU. It is suggested that the present experimental paradigm could be a useful assessment tool for the evaluation of display design.

Component problems in dichotic listening

The experiments reported examined monitoring for semantically defined targets whilst concurrently shadowing (Experiment I) or listening silently (Experiment II). The word lists for monitoring were either visual or auditory. Monitoring and shadowing accuracy showed less interference when presentation was bimodal than when it was dichotic. However, monitoring latency and recognition memory for shadowed material did not show this effect. It is argued that these data reveal the existence of a number of different sources of potential difficulty in dichotic listening situations and the nature of these is discussed.

Working memory and reasoning: An individual differences perspective

This article reports three experiments that investigated the relationship between working memory capacity and syllogistic and five-term series spatial inference. A series of complex and simple verbal and spatial working memory measures were employed. Correlational analyses showed that verbal and spatial working memory span tasks consistently predicted syllogistic and spatial reasoning performance. A confirmatory factor analysis showed that three factors best accounted for the data—a verbal, a spatial, and a general factor. Syllogistic reasoning performance loaded all three factors, whilst spatial reasoning loaded only the general factor. The implications of these findings are discussed in the context of reasoning theories and contemporary accounts of the structure of working memory.