David A. Kobus

Age-dependent magnitude and time course of early light adaptation

Crawford (1947) demonstrated that large and rapid changes in visual sensitivity accompany an abrupt increase in retinal illumination. This has been referred to as early light adaptation (ELA) in order to distinguish these initial adjustments from those occurring after the eye has become more fully light adapted (White, Kelly, & Sturr, 1978). Although much research has been carried out on ELA, the underlying mechanisms remain unknown. As part of a baseline condition for a recent ELA study in our laboratory (Kelly, 1979), ELA functions were measured on a large homogeneous field. Four observers showed a large threshold rise at the onset of the adapting field, with an exponential decay to steady-state level. However, a fifth observer repeatedly failed to show the large threshold overshoot. Following considerable effort to determine the cause of this difference, we suspected that age might be a major variable. The subject with the anomalous results was 47 years old, whereas all the others were in their 20s. Since there is a growing body of evidence documenting losses in temporal response properties of the aging visual system (Eriksen, Hamlin, & Breitmeyer, 1970; Kline & Orme-Rogers, 1978; Kline & Schieber, 1981; Pollack, 1978; Walsh, 1976), we postulated that the ELA function would also manifest age-dependent changes. This report describes a study designed to test this hypothesis.

The future of augmented cognition systems in education and training

As adaptive interfaces increase in sophistication and application, augmented cognition systems are becoming accessible to a wider variety of users in real-world settings. The potential for using closed-loop augmented cognition systems in education and training is immense, and will be instrumental in meeting growing demands for distance learning and remote training. Augmented cognition technologies can be applied in numerous ways to dynamically tailor instruction to the users cognitive style and skill level. Examples of such applications are discussed, along with their implications for enhanced educational and training programs of the future.

NEUROPSYCHOLOGICAL IMPLICATIONS OF HAND PREFERENCE VERSUS HAND GRIP PERFORMANCE

Hand-grip strength, measured by a hand dynamometer, was compared with hand preference for writing in a sample of 173 male and female undergraduate students. Hand preference and performance correlated significantly, but superiority of hand grip for 24% of the subjects did not coincide with the preferred hand. Hand-grip performance was not an accurate predictor of hand preference, and neuropsychological inferences on the basis of hand performance should be made cautiously. No significant differences were found between the right/left ratio scores for males and females, or order conditions.

Augmenting task-centered design with operator state assessment technologies

Task-Centered Design (TCD) of human-system interfaces focuses on supporting the user throughout all phases of tasks, from initiation to completion. TCD typically requires software that monitors aspects of system information to trigger tasks, develop user-friendly information sets, propose task solutions and actions, and confirm actions as directed and approved by the operator. The operator monitors tasks awaiting completion on a Task Manager display. We demonstrate that moment-to-moment operator workload monitoring is greatly facilitated by TCD. Workload estimates were obtained every 2-min over the course of a 35-min test session during an air defense command and control scenario. Workload was readily modeled by the task loading, and the density of track icons on the display. A second study related the unitary workload estimates to NASA TLX workload subscales. Unpublished data from our laboratory indicated that eye activity measures (e.g., blink frequency and duration, pupil diameter, fixation frequency and dwell time) did not improve the estimation of workload. These findings indicate that at least for well-executed TCD systems, eye tracking technologies may be best employed to monitor for fatigue and incongruities between the focus of attention and task requirements. Recent findings using EEG hold promise for the identification of specific brain signatures of confusion, orientation, and loss of situational awareness. Thus the critical element of human directed systems is good initial design. Understanding of the task will lead to system automation that can balance the workload of the operator, who is functioning in a normal state. However, physiological monitoring will be most useful if operators veer beyond their normal conditions and are confused, overloaded, disoriented or have other impairments to their abilities. By detecting the operators loss of function early, inappropriate operator inputs can potentially be avoided.

READING DISABILITY: A HEMISPHERIC ASYMMETRY-INFORMATION PROCESSING APPROACH

A visual half-field task using a Sperling partial-report paradigm was presented to 10 reading disabled and 10 control subjects (7 to 14 yr. old). The design was very similar to that described in 1977 by Morrison, Giordani, and Nagy, examining performance of letters placed in a circular array at both the perceptual and short-term memory stage. The reading-disabled subjects performed significantly lower on letter-recognition during both the perceptual and short-term memory processing stages. A hemi-field analysis showed a left visual-field performance decrement for the reading-disabled group during the short-term memory stage. Contrary to previous findings which discount a perceptual deficit, this study indicates that such a deficit may exist and is further accentuated during the short-term memory stage by a decrement in right-hemisphere performance.