Gail A. Fontenelle

Effectiveness of Warnings

The purpose of the present work was to identify some of the factors that influence effectiveness of warnings. Two laboratory experiments designed to examine behavioral effectiveness indicated that a warning placed before procedural instructions is more likely to lead to compliance than a warning that follows instructions. Two rating experiments indicated that for greatest perceived effectiveness, environmental warnings generally require a signal word plus hazard, consequence, and instruction statements. A third rating experiment suggested that informative, nonredundant statements add to a warnings perceived effectiveness. Several field demonstration studies showed that cost of compliance and salience influence behavioral effectiveness. Implications and applications to warning design are discussed.

The Effects of the Application on Recall of Information from the Interview

Two laboratory experiments were conducted to test the extent to which initial impressions of applicants formed from paper credentials bias information recalled from interviews with these applicants...

Generalizing across stimuli as well as subjects: A neglected aspect of external validity.

In order to generalize the results of an experiment beyond the specific stimuli employed, it is necessary to consider variance due to stimulus sampling. This can be accomplished by treating stimuli as a random effect rather than the traditional procedure of treating stimuli as a fixed effect. The serious consequences of the traditional approach are illustrated using examples from applied psychology. Statistical and design considerations for generalizing the results of experiments are discussed.

Behavioral Effectiveness of Warnings

A paradigm was developed to examine the effectiveness of warnings in a laboratory task. A task was presented to subjects as one examining how people perform a basic chemistry demonstration. Experiment 1 examined the effects of two locations of the warning (before and after instructions) and two different signal word presentations (WARNING and Note). An additional condition with no warning or signal word served as a control. No effects were found on time or accuracy. However, compliance (use of mask and gloves) was affected by the inclusion of the warning as well as by its location. Greatest compliance occurred when the warning was placed prior to the instructions. Experiment 2 replicated the effect of location. The addition of a printed statement placed before the instructions (with warning at the end) to read through the instructions before beginning produced intermediate compliance that was not significantly different from the warning beginning and end conditions. Observation revealed that when the warning message was at the end of the instructions subjects complied only when they saw the warning message before starting the task. These results indicate that if warnings are placed in front of instructions the consumer is more likely to read and comply.

A Manpower Determination Aid Based upon System Performance Requirements

This paper discusses two of the six software tools which are being developed as part of the Army Research Institutes MANPRINT Methods development program. The first tool discussed here is known as the System Performance and RAM Constraints Aid or SPARC. This tool permits system designers to determine levels of subfunction performance which are required to achieve function and higher level mission requirements. These levels of subfunction and function performance then serve as requirements which are fed into the second tool, the Manpower Systems Evaluation Aid (MAN-SEVAL). MAN-SEVAL takes as input the system design and then predicts the operator and maintainer manpower required to achieve the required levels of task and function performance. For maintenance manpower evaluation, MAN-SEVAL considers component failure rates, time to perform maintenance, and the mission scenario. For operator manpower and to estimate maintenance task times, MAN-SEVAL conducts an analysis of workload, control/display accessability, and maximum acceptable performance time to allocate tasks across crewmembers. Because all manpower requirements are truly driven by system performance requirements, these two tools are being developed collectively with common data bases and software design. While they are currently being developed for the Army, they will be useful general purpose manpower analysis tools.

Isometric Strength Tests: Predicting Performance in Physically Demanding Transport Tasks

A study explored the applicability of a battery of four isometric strength tests to steward, utility and warehouse jobs in a company that services offshore drilling and production facilities in the petroleum industry. The jobs involve frequently transporting materials up stairs, a category of tasks not prominent in situations where these tests have previously been applied. A job analysis established critical task requirements such as procedures, weights, distances, sizes of containers, etc. An experiment was then carried out with 25 male and 25 female subjects. The subjects performed two self-paced job-related tasks: transporting a 15.9 kg box up and down stairs and similarly transporting a 22.7 kg box. Measures included heart rate and amount of work performed, which, along with known task parameters, was used to calculate work power. Subjects also performed four standard isometric strength tests: grip, arm lift, back lift and arm press. Correlations between job task and strength performance indicated these tests are applicable to jobs with such requirements, thus extending the generalizability of the strength test battery.

A Workload Assessment Aid for Human Engineering Design

The Workload Assessment Aid (WAA) is a software tool developed for the Army Research Institute as part of the MANPRINT effort. This software toolkit is specifically designed to predict operator workload at the earliest stages of design. It builds upon a task network simulation tool, Micro SAINT, by incorporating several other predictive workload techniques, in addition to several new dimensions. In its final form the tool will automatically make task reallocation recommendations based on workload profiles, personnel characteristics and display-control accessibility.

A contrast of guideline recommendations and Tullis's prediction model for computer displays: Should text be left-justified?

Two experiments investigated the effect of layout complexity for performance at varying levels of practice on four types of information extraction tasks. Layout complexity is defined as the number of unique horizontal and vertical starting positions of items in the display (Tullis, 1984). In the first study, layout complexity was manipulated by either left-justifying or not left-justifying text. In the second study, subject veiwed a third experimental screen that displayed the starting positions of items in a completely unpredictable pattern. Moderate violations of the typical guideline recommendation that alphanumeric data be left-justified did not increase user search time across all four tasks in either the first or second study. Furthermore, severe violations of the recommendation did not increase user search time for three tasks (find label, scan data, and compare label). However when subjects compared multiple data values, the random format did increase user search time. Though performance using the three experimental screens was comparable across the four tasks with only one exception, subjective ratings demonstrated differences between the three formats.

Scenario Analysis of Children's Ingestion Accidents

This paper reports the results of a scenario analysis of ingestion accidents involving children under five years of age. The variables of primary interest were the location of the child and the supervising adult, what each of them was doing before the accident, the nature and location of the substance, and how it was accessed and opened. Several frequent scenarios were identified. They indicate that most ingestion accidents happen in the course of normal events in the home rather than under unusual circumstances. Another interesting finding was that products with safety caps were involved in 57% of these cases. Results demonstrate the need for a modification of cap design and a public education program for parents regarding situations that lead to ingestion accidents.