Donald A. Schumsky

Recalculation of the Critical Values for Lawshe’s Content Validity Ratio

The content validity ratio (Lawshe) is one of the earliest and most widely used methods for quantifying content validity. To correct and expand the table, critical values in unit steps and at multiple alpha levels were computed. Implications for content validation are discussed.

Target Acquisition with UAVS: Vigilance Displays and Advanced Cuing Interfaces

Vigilance and threat detection are critical human factors considerations in the control of unmanned aerial vehicles (UAVs). Utilizing a vigilance task in which threat detections (critical signals) led observers to perform a subsequent manual target acquisition task, this study provides information that might have important implications for both of these considerations in the design of future UAV systems. A sensory display format resulted in more threat detections, fewer false alarms, and faster target acquisition times and imposed a lighter workload than did a cognitive display format. Additionally, advanced visual, spatial-audio, and haptic cuing interfaces enhanced acquisition performance over no cuing in the target acquisition phase of the task, and they did so to a similar degree. Thus, in terms of potential applications, this research suggests that a sensory format may be the best display format for threat detection by future UAV operators, that advanced cuing interfaces may prove useful in future UAV systems, and that these interfaces are functionally interchangeable.

Listening with a dual brain: Hemispheric asymmetry in sustained attention

Subjects listened for increments in the duration of recurrent white-noise pulses during an 80-min vigil. Critical signals for detection appeared in either a temporally regular or an irregular manner while acoustic stimulation was delivered either binaurally or monaurally to the left or to the right ear. Temporal regularity had no significant effect on performance, but performance was influenced by the input conditions and by time on task. Response times (RTs) to the detection of binaural and left-ear signals had a common origin and increased in a negatively accelerated fashion over time. By contrast, RTs to right-ear signals were relatively sluggish early in the vigil and remained stable over time. The results suggest a functional asymmetry in hemispheric organization during the maintenance of sustained attention.

Target Acquisition with UAVS: Vigilance Displays and Advanced Cueing Interfaces

Future Uninhabited Aerial Vehicles (UAVs) will require operators to switch quickly and efficiently from supervisory to manual control. Utilizing a vigilance task in which threat detections (critical signals) led observers to perform a subsequent manual target acquisition task, the present investigation revealed that the type of vigilance display might have important design implications for future UAV systems. A sensory display format resulted in more threat detections, fewer false alarms, and faster target acquisition times and imposed a lighter workload than a cognitive display format. Thus, the former may be the best display arrangement for future UAV controllers. Additionally, advanced visual, spatial audio, and haptic cueing interfaces enhanced acquisition performance over no cueing in the target acquisition phase of the task, and did so to a similar degree. This finding suggests that advanced cueing interfaces may also prove useful in future UAV systems and that these interfaces are functionally interchangeable.

Ear asymmetry and the temporal uncertainty of signals in sustained attention

Subjects listened for increments in the duration of recurrent white noise pulses delivered to either the left or the right ear during a 1-h vigilance session. The temporal uncertainty of critical signal occurrences was varied by use of signal densities of 24, 48, and 96 signals/hour. Response times to signal detections increased as a function of an information measure of the temporal uncertainty of signals with a markedly stronger effect from left-ear presentation. Thus, a functional lateral asymmetry in the cortical processing of temporal information in this type of task was indicated.

Human operant eyelid conditioning: Auditory vs visual reinforcing signal

The human eyeblink response was conditioned as a free operant, employing a double-blind yoked-control procedure. High levels of conditioning were obtained with experimental Ss by employing either a visual or auditory reward signal. No significant differences in response level were associated with reward signal modality in conditioning nor, as previously hypothesized, for yoked controls. Evidence for a significant conditioning effect was obtained even when the data of only “unaware” Ss were considered.

Intra-list interference in single trial short-term memory

In a group testing procedure, 480 Ss were given a single trial to learn a list of five nonsense syllables, presented one at a time in order. Ss were given an interpolated interval of 0, 15, or 30 sec in which they were required to cancel vowels from lists of random letters. At the end of the interval they were required to recall either the first, middle, or last syllable in the list. Results revealed a significant effect associated only with serial position.

Free operant conditioning of the human eyelid response

A yoked control double blind procedure was employed to demonstrate the free operant conditioning of the human eyelid response with reward. A high rate of conditioning was obtained for experimental Ss when compared to their initial operant level and/or the yoked controls. A statistically reliable conditioning effect was obtained even when the analysis included only those Ss unable to verbalize the response reward contingency relationship (“unaware Ss”).

Retrieval of attribute information as a function of processing depth

The effects of processing depth on retrieval of attribute information was investigated using a modified probe-recognition procedure. Subjects decided whether a probe word was a synonym, a homonym, identical to, or not related to any word of a previously presented three-word set. Depth of processing was manipulated by priming with a dimensional cue prior to the presentation of the study set. The dimensional cue specified the relation in question between probes and potential target words in each study set. Effects were assessed relative to unprimed conditions where subjects had the dimensional relation specified during probe presentation. The probe word followed the three-word set by a 0-, 10-, or 30-sec filled or unfilled delay. Priming effects were reflected in reaction time but not recognition accuracy, with degree of effect related to level of processing. Synonyms were affected most, homonyms next, identity least.

Sustained Attention and Feature-Integrative Displays

Observers monitored the repetitive presentation of a simulated submarine detection display for occasional targets. Observers were required to integrate information contained in one, two, or three indicators either in a simultaneous (comparative judgment) or successive (absolute judgment) format. Consistent with earlier findings on feature-integration, performance efficiency varied inversely with the number of features which needed to be integrated in signal detection. Unlike previous studies involving unitary discriminations, observers in the simultaneous conditions performed more poorly than those in the successive conditions as the information processing demands of the monitoring task increased. The results indicate that while systematic differences were found between simultaneous and successive task-types, different factors may play a role when observers must contend with multiple as compared to unitary sources of information.