Suchergebnisse

Three groups of ten subjects each performed a unidimensional compensatory tracking task for 30 minutes. Each group received continuous error information feedback either visually, auditorally, or cutaneously. Direction of error was signaled by the side of the body stimulated, magnitude of error was indicated by signal intensity. Intensities of the signals were subjectively matched. Performance was measured by time on target, constant error, absolute error, and root-mean-square error. Analyses of variance for these measures yielded significant differences between display types on all but the root-mean-square measure. A multiple discriminate analysis was performed on these measures and provided two significantly independent dimensions of discrimination. The first dimension was defined as "speed of response," the second "goodness of performance." It was concluded that for the particular task used, the auditory and cutaneous displays proved more effective than the visual display.

This investigation examined potential performance or motivational differences between self-paced and machine-paced inspection tasks, and measured subject perceptions of inspection tasks. Twenty women served as inspectors in the investigation. Subjects in both self-paced and machine-paced conditions inspected simulated printed circuits varying in circuit complexity. Performance measures of defect detection rate, false alarm rate, and time required for decision were recorded. Self-paced subjects performed better, but both groups suffered performance decrements on the more complex circuits. Both groups found the task basically dull and uninteresting.

The purpose of the present study was to determine the effects of continuous white noise on visual target-detection performance. The variables manipulated were noise-intensity level, display-difficulty level, and target location. Four noise levels were utilized: 0, 80, 90, and 100 db. The 0-db. level served as the control condition. Display difficulty was defined in terms of the number of nontarget, or background, display elements. Three levels of difficulty were used: 8, 16, and 32 background letter characters. The target locations examined were the central and peripheral regions of the visual display. Twenty subjects were tested under all conditions. Both detection time and detection error were recorded. The results indicated that noise-intensity and display-difficulty level were significantly interrelated with respect to detection speed but not to detection error.

Eighteen subjects performed a velocity judgment task in which a target was displayed briefly and then disappeared from view. The subjects were required to estimate the time taken by the target to reach a final goal position. When the time data were converted to velocity estimates (concealment distance divided by concealment time estimate), a linear relationship between the mean and standard deviation of the estimated velocity was observed. A greater magnitude of error was associated with the slow target speeds than with the fast speeds, and with the long rather than the short concealment distances. Two distinct response patterns were evident when constant error was used as the time error measure. Some subjects responded with increasing negative constant error to decreases in target speed and increases in concealment distance, while other subjects responded to the same conditions with increased positive constant error. Differential perceptual responses to differences in task difficulty are proposed to account for these results.