Lindsey K. McIntire

Detection of vigilance performance using eye blinks.

Research has shown that sustained attention or vigilance declines over time on task. Sustained attention is necessary in many environments such as air traffic controllers, cyber operators, and imagery analysts. A lapse of attention in any one of these environments can have harmful consequences. The purpose of this study was to determine if eye blink metrics from an eye-tracker are related to changes in vigilance performance and cerebral blood flow velocities. Nineteen participants performed a vigilance task while wearing an eye-tracker on four separate days. Blink frequency and duration changed significantly over time during the task. Both blink frequency and duration increased as performance declined and right cerebral blood flow velocity declined. These results suggest that eye blink information may be an indicator of arousal levels. Using an eye-tracker to detect changes in eye blinks in an operational environment would allow preventative measures to be implemented, perhaps by providing perceptual warning signals or augmenting human cognition through non-invasive brain stimulation techniques.

A Comparison of the Effects of Transcranial Direct Current Stimulation and Caffeine on Vigilance and Cognitive Performance During Extended Wakefulness

BACKGROUND Sleep deprivation from extended duty hours is a common complaint for many occupations. Caffeine is one of the most common countermeasures used to combat fatigue. However, the benefits of caffeine decline over time and with chronic use. OBJECTIVE Our objective was to evaluate the efficacy of anodal transcranial direct current stimulation (tDCS) applied to the pre-frontal cortex at 2 mA for 30 min to remediate the effects of sleep deprivation and to compare the behavioral effects of tDCS with those of caffeine. METHODS Three groups of 10 participants each received either active tDCS with placebo gum, caffeine gum with sham tDCS, or sham tDCS with placebo gum during 30 h of extended wakefulness. RESULTS Our results show that tDCS prevented a decrement in vigilance and led to better subjective ratings for fatigue, drowsiness, energy, and composite mood compared to caffeine and control in sleep-deprived individuals. Both the tDCS and caffeine produced similar improvements in latencies on a short-term memory task and faster reaction times in a psychomotor task when compared to the placebo group. Interestingly, changes in accuracy for the tDCS group were not correlated to changes in mood; whereas, there was a relationship for the caffeine and sham groups. CONCLUSION Our data suggest that tDCS could be a useful fatigue countermeasure and may be more beneficial than caffeine since boosts in performance and mood last several hours.

Acceleration of Image Analyst Training With Transcranial Direct Current Stimulation

Humans today are routinely and increasingly presented with vast quantities of data that challenge their capacity for efficient processing. To restore the balance between man and machine, it is worthwhile to explore new methods for enhancing or accelerating this capacity. This study was designed to investigate the efficacy of transcranial DC stimulation (tDCS) to reduce training time and increase proficiency in spatial recognition using a simulated synthetic aperture radar (SAR) task. Twenty-seven Air Force active duty members volunteered to participate in the study. Each participant was assigned to 1 of 3 stimulation groups and received two, 90-min training sessions on a target search and identification task using SAR imagery followed by a test. The tDCS anode was applied to site F10 according to the 10-20 electroencephalographic electrode convention while the cathode was placed on the contralateral bicep. Group 1 received anodal tDCS at 2 mA for 30 min in the first training session and sham tDCS in the second session. Group 2 received the stimulation conditions in the opposite order. Group 3 did not receive stimulation at all. Results showed that participants receiving training plus tDCS attained visual search accuracies ~25% higher than those provided with sham stimulation or no stimulation. However, a corresponding performance improvement was not found in the first training session for the change detection portion of the task. This indicates that experience with the imagery is important in the tDCS-elicited performance improvements in change detection.

Detection of vigilance performance with pupillometry

Sustained attention (vigilance) is required for many professions such as air traffic controllers, imagery analysts, airport security screeners, and cyber operators. A lapse in attention in any of these environments can have deadly consequences. The purpose of this study was to determine the ability of pupillometry to detect changes in vigilance performance. Each participant performed a 40-minute vigilance task while wearing an eye-tracker on each of four separate days. Pupil diameter, pupil eccentricity, and pupil velocity all changed significantly over time (p<.05) during the task. Significant correlations indicate that all metrics increased as vigilance performance declined except for pupil diameter, which decreased and the pupil became miotic. These results are consistent with other research on attention, fatigue, and arousal levels. Using an eye-tracker to detect changes in pupillometry in an operational environment would allow interventions to be implemented.

A variety of automated turing tests for network security: Using AI-hard problems in perception and cognition to ensure secure collaborations

There are a multitude of collaborative and network applications that are vulnerable to interference, infiltration, or attack by automated computer programs. Malicious programs can spam or otherwise disrupt email systems, blogs, and file sharing networks. They can cheat at online gaming, skew the results of online polls, or conduct denial-of-service attacks. And sophisticated AI “chat-bots” can pose as humans in order to gather intelligence from unsuspecting targets. Thus, a recurring problem in collaborative systems is how to verify that a user is a human and not a computer. Following the work of Coates et al. [1], von Ahn et al. [2], and others, we propose several AI-hard problems in perception and cognition that can serve as “CAPTCHAs,” or tests capable of distinguishing between human-level intelligence and artificial intelligence, ensuring that all collaborators interfacing a particular system are humans and not nefarious computer programs.

Augmenting Visual Search Performance with Transcranial Direct Current Stimulation (tDCS)

Military personnel endure rigorous and demanding man-hours designated to monitoring and locating targets in tasks such as cyber defense and Unmanned Aerial Vehicle (UAV) operators. These tasks are monotonous and repetitive, which can result in vigilance decrement. The objective of the study was to implement a form of noninvasive brain stimulation known as transcranial DC stimulation (tDCS) over the left frontal eye field (LFEF) region of the scalp to improve cognitive performance. The participants received anodal and cathodal stimulation of 2 mA for 30 min as well as placebo stimulation on 3 separate days while performing the task. The findings suggest that anodal and cathodal stimulation significantly improves detection accuracy. Also, a correlation was detected between percent of eye closure (PERCLOS) and blinking frequency in relation to stimulation condition. Our data suggest that tDCS over the LFEF would be a beneficial countermeasure to mitigate the vigilance decrement and improve visual search performance.

Eye Metrics: An Alternative Vigilance Detector for Military Cyber Operators

Military operators in various environments such as cyber, remotely piloted aircraft, and image analysis are required to use sustained attention or vigilance for long periods. During this time they encounter lapses in attention attributable to the monotonous nature of their tasks. Mistakes during these tasks can have serious consequences. The purpose of this study was to investigate the use of an eye-tracker to detect changes in vigilance performance during a simulated cyber operator task. Twenty participants performed 4 sessions of a 40-min vigilance task while wearing an eye-tracker. Blink frequency, blink duration, PERCLOS (percentage of eye closure), pupil diameter, pupil eccentricity, pupil velocity, and signal detection all had a significant change over time (p < .05) during the task. The significant change of oculometric measurements indicates oculometrics could be used to detect changes in vigilance for military operators. Future research is needed to assess real-time effects of these oculometrics on performance, especially in a real-world setting.

Methods for chatbot detection in distributed text-based communications

Distributed text-based communications (e.g., chat, instant-messaging) are facing the growing problem of malicious “chatbots” or “chatterbots” (automated communication programs posing as humans) attempting social engineering, gathering intelligence, mounting phishing attacks, spreading malware and spam, and threatening the usability and security of collaborative communication platforms. We provide supporting evidence for the suggestion that gross communication and behavioral patterns (e.g., message size, inter-message delays) can be used to passively distinguish between humans and chatbots. Further, we discuss several potential interrogation strategies for users and chat room administrators who may need to actively distinguish between a human and a chatbot, quickly and reliably, during distributed communication sessions. Interestingly, these issues are in many ways analogous to the identification problem faced by interrogators in a Turing Test, and the proposed methods and strategies might find application to and inspiration from this topic as well.

The Effects of Transcranial Direct Current Stimulation (tDCS) on Training During a Complex Procedural Task

There is a growing body of literature suggesting transcranial direct current stimulation (tDCS) is effective in accelerating certain types of memory including working memory, language learning, and object recognition. Recent studies have provided new evidence that non-declarative memories such as motor skill acquisition may be enhanced through direct stimulation of motor cortex. Additionally, Galea and Celnik (J Neurophysiol 102:294–301, [10]) showed that inhibition of the prefrontal cortex following motor training led to enhanced procedural memory consolidation. This effort examined the effects of excitatory transcranial direct current stimulation (tDCS) over the primary motor cortex on memory acquisition and inhibitory tDCS over dorsolateral prefrontal cortex in memory consolidation. Thirty-six Air Force members volunteered to participate. They were divided into four groups: anodal tDCS over motor cortex, cathodal stimulation over dorsolateral prefrontal cortex (DLPFC), both anodal tDCS over motor cortex and cathodal tDCS over DLPFC, or sham tDCS over motor cortex and DLFPC. All participants received their stimulation condition while training on a procedural task that required them to identify incoming aircraft as friend or foe. Twenty-four hours after the training session, participants returned to the lab for retention testing. When comparing the day 1 (training) scores to the day 2 (test) score, the results showed the cathodal tDCS group performed 2× better than sham and all real tDCS groups exhibited scores significantly higher than sham. The evidence suggests that inhibition of the prefrontal cortex leads to the greatest improvement in performance. We hypothesize that this is a result of a shift in dominance of the declarative memory system to the non-declarative procedural system, which improves consolidation of the procedural memories gained during training.

Ideas on authenticating humanness in collaborative systems using AI-hard problems in perception and cognition

Collaborative applications including email, chat, file-sharing networks, blogs, and gaming are under constant threat of automated programs that are gaining access to, attacking, degrading, or otherwise disrupting the intended communications and interactions. Thus, an important issue in collaborative systems security is how to verify that a user is a human, and not a computer attempting to access the system for malicious purposes. We propose and discuss several AI-hard examples from perception and cognition that may be useful for distinguishing between human-level intelligence and artificial intelligence.