No abstract

The integration of real-time electroencephalogram (EEG) workload indices into the man-machine interface could greatly enhance performance of complex tasks, transforming traditionally passive human-system interaction (HSI) into an active exchange where physiological indicators adjust the interaction to suit a user's engagement level. The envisioned outcome is a closed-loop system that utilizes EEG and other physiological indices for dynamic regulation and optimization of HSI in real-time. As a first step towards a closed-loop system, five individuals performed as identification supervisors (IDSs) in an Aegis command and control (C 2 ) simulated environment, a combat system with advanced, automatic detect-and-track, multi-function phased array radar. The Aegis task involved monitoring multiple data sources (i.e., missile-tracks, alerts, queries, resources), detecting required actions, responding appropriately, and ensuring system status remains within desired parameters. During task operation, a preliminary workload measure calculated in real-time for each second of EEG and was used to manipulate the Aegis task demands. In post-hoc analysis, the use of a five-level workload measure to detect cognitively challenging events was evaluated. Events in decreasing order of difficulty were track selection-identification, alert-responses, hooking-tracks, and queries. High/extreme EEG-workload occurred during high cognitive-load tasks with a detection efficiency approaching 100% for selection-identification and alert-responses, 77% for hooking-tracks and 70% for queries. Over 95% of high/extreme EEG-workload across participants occurred during high-difficulty events (false positive rate < 5%). The high/extreme workload occurred between 25-30% of time. These results suggest an intelligent closed-loop system incorporating EEGworkload measures could be designed to re-allocate tasks and aid in efficiently streamlining a user's cognitive workload. Such an approach could ensure the operator remains uninterrupted during high/extreme workload periods, thereby resulting in increased productivity and reduced errors.

2003. Honesty in host-parasite communication signals: the case for begging by fledgling brown-headed cowbirds Molothrus ater. -J. Avian Biol. 34: 339-344.Nestling parasites typically beg more intensively than do host nestlings yet these exaggerated displays are also honest in that they are modulated by hunger and age. We hypothesized that honesty was also maintained in the food solicitation behaviors of fledgling brood parasites because the benefits and costs of their begging displays are similar to those of nestling parasites. Begging displays of hand-reared 14 -32 days old brown-headed cowbirds Molothrus ater that had experimentally manipulated nutritional needs were recorded to analyze variation in the peak frequency, duration, and rate of fledglings' begging bouts. Peak frequency of bouts decreased with greater age and was lower for females. Bout rate was greater with increasing hunger levels of fledgling parasites but did not vary with age. Consistent and predictable variation of acoustic begging displays with age, sex, and hunger-level indicates honesty in host-parasite communication systems through conveying truthful information about the many possible needs of parasitic fledglings.