Yael Salzer

Vibrotactile “On-Thigh” Alerting System in the Cockpit

Background: Alerts in the cockpit must be robust, difficult to ignore, and easily recognized. Tactile alerts can provide means to direct the pilot’s attention in the already visual-auditory overloaded cockpit environment. Objective: This research examined the thigh as a placement for vibrotactile display in the cockpit. The authors (a) report initial findings concerning the loci and properties of the display, (b) evaluate the added value of tactile cuing with respect to the existing audio-visual alerting system, and (c) address the issue of tactile orienting—whether the cue should display “flight” or “fight” orienting. The tactor display prototype was developed by a joint venture of Israel Aerospace Industries, Lahav Division, and the Ben Gurion University of the Negev (patent pending 11/968,405). Method: A vibrotactile display mounted on the thigh provided directional cues in the vertical plane. Two vibrotactile display modes (eight and four tactors) and two response modes (compatible, i.e., fight [toward vibrotactile cue], and inverse, i.e., flight [away from vibrotactile cue]) were evaluated. Results: Vertical directional orienting can be achieved by a vibrotactile display assembled on the thigh. The four-tactor display mode and the compatible response mode produced more accurate results. Conclusion: Tactile cues can provide directional orienting in the vertical plane. The benefit of adding compatible tactile cues compared with visual and auditory cues alone has yet to be reinforced. Nevertheless, fight mode, that is, directing the way to escape from hazardous situations, was preferred. Application: Potential applications include providing directional collision alerts within the vertical plane, assisting pilot’s elevation control, or navigation.

In Touch With the Simon Effect *The first two authors contributed equally.

Cognitive control has been extensively studied using the auditory and visual modalities. In the current study, a tactile version of the Simon task was created in order to test control mechanisms in a modality that was less studied, to provide comparative and new information. A significant Simon effect--reaction time gap between congruent (i.e., stimulus and response in the same relative location) and incongruent (i.e., stimulus and response in opposite locations) stimuli--provided grounds to further examine both general and tactile-specific aspects of cognitive control in three experiments. By implementing a neutral condition and conducting sequential and distributional analysis, the present study: (a) supports two different independent mechanisms of cognitive control--reactive control and proactive control; (b) reveals facilitation and interference within the tactile Simon effect; and (c) proposes modality differences in activation and processing of the spatially driven stimulus-response association.

Vibrotactor-belt on the thigh: directions in the vertical plane

This multiple phase research examines the utility of the thigh as a placement for a vibrotactile display in the cockpit. The initial phase of this research is presented hereby. Vibrotactile displays designed to convey horizontal directional waypoints or warnings are commonly situated on the torso of the pilot. Here, an eight-tactors belt prototype fixed around the thigh of a seated operator was used to convey vertical directional waypoints. Localization accuracy was examined. Analysis revealed that vibrotactile cues embracing the thigh are discriminated in a similar manner to the torso, providing initial evidence that vibrotactile signaling on the thigh can provide directional cues in the vertical plane.

Evaluation of an “On-Thigh” Vibrotactile Collision Avoidance Alerting Component in a Simulated Flight Mission

Tactical collision avoidance systems (TCAS) aim to promote aerospace safety by improving the situational awareness of helicopter pilots and reducing the likelihood of collisions. TCAS stimuli must be noticeable even with the multitude of visual and auditory stimuli the pilot must process during flight. To improve the salience of TCAS, a tactile on-thigh display component was added to the design. In a simulated task, participants were asked to conduct a flight mission, while searching for specific visual landmarks along the flight path and to respond to abrupt directional visual and/or tactile alerting cues. The addition of the tactile cues improved response accuracy and shortened response time to the warning. In addition, although it did not interfere with the ability to maintain flight control, participant recollection of the landmark targets they had identified was least successful in the presence of the tactile modality. Implications for design are discussed.

A comparison of "on-thigh" vibrotactile, combined visual-vibrotactile, and visual-only alerting systems for the cockpit under visually demanding conditions

In the cockpit, performance is prone to break down. Conveying crucial information through the tactile modality, which requires little to no additional effort, has been previously examined as means to improve performance and safety. Previously, we demonstrated the ability of the on-thigh vibrotactile alerting display to convey directional cues in the vertical plane. We hypothesized that tactile directional alerting cues would be beneficial in a visually loaded multi-tasking environment. In the current study, two tasks were introduced simultaneously: a directional task where participants respond to directional cues (visual, tactile, or combination of both), and a visual-memory recall task where participants identify, count and recall objects embedded in flight movies. Response time, accuracy and subjective workload were evaluated. Performance in the memory recall task and subjective workload were in favor of the combined tactile & visual configuration. No performance difference was found between visual and tactile & visual in the directional task. We conclude that the tactile & visual configuration may allow operators to choose a strategy in which perceptual and cognitive resources are better utilized.

Thermoelectric tactile display based on the thermal grill illusion

Motivation -- Our goal was to design a thermal tactile display based on the thermal grill illusion sensation (created with spatially adjacent warm and cold stimuli), and to explore perception of information with such display. Research approach -- A prototype of a Thermoelectric Tactile Display (TTD) was developed, based on Thermoelectric Coolers (TEC) Peltier technology. Temporal and spatial manipulations of signals will lead to definition of optimal TTD parameters, and to mapping of the sensory perception. Findings -- Currently at initial stages of the experimentation of TTD prototype, findings indicate clear and distinguishable sensations. The TTDs performance is supported by an analytical model. Research Limitations -- Pilot study with limited number of participants Originality -- This study expands the knowledge and availability of tactile-modalities. The majority of tactile interfaces used in research and applied settings are based on vibration and pressure. No previous references show the use of thermal displays as a stand-alone signal source, nor is there evidence of the use of the thermal grill illusion for that purpose. It is the first use of TEC technology for generating thermal grill stimuli. Take away message -- TTD opens a new channel of tactile communication, whose optimal parameters and functionality needs yet to be fully determined.

The interaction between emotion and executive control: Comparison between visual, auditory, and tactile modalities

The reciprocal connections between emotion and attention are vital for adaptive behaviour. Previous results demonstrated that the behavioural effects of emotional stimuli on performance are attenuated when executive control is recruited. The current research studied whether this attenuation is modality dependent. In two experiments, negative and neutral pictures were presented shortly before a visual, tactile, or auditory target in a Simon task. All three modalities demonstrated a Simon effect, a conflict adaptation effect, and an emotional interference effect. However, the interaction between picture valence and Simon congruency was found only in the visual task. Specifically, when the Simon target was visual, emotional interference was reduced during incongruent compared to congruent trials. These findings suggest that although the control-related effects observed in the Simon tasks are not modality dependent, the link between emotion and executive control is modality dependent. Presumably, this link occurs only when the emotional stimulus and the target are presented in the same modality.

Simon in action: the effect of spatial congruency on grasping trajectories.

The Simon effect, one of the well-known stimulus–response compatibility effects, is usually explained as an expression of a conflict that occurs at the response selection stage. Here, we extended previous findings to provide evidence for post-response selection expression of the Simon effect. Following a presentation of a visual stimulus, participants grasped one of two objects that differed slightly in size. The results showed that visual stimulus congruency modulated grasping trajectories. Particularly, movements were more lateralized in congruent trials. This lateralization decreased as reaction time (RT) increased and therefore this effect could not be fully dissociated from the response selection stage. However, size sensitivity, as measured by the time taken to reach the maximum grip aperture between the fingers, was decreased for incongruent trials, unrelated to RT. This finding provides novel evidence for an independent expression of the Simon effect in post-response selection stages. Overall, our findings extend previous studies and demonstrate that the spatial conflict evoked by the Simon task encompasses several components and independently affects response selection stages as well as other components of motor execution.

Tactile Interfaces for Dismounted Soldiers: User-perceptions on Content, Context and Loci

In military operational environments, an overflow of information along with rapidly changing conditions has the potential to reduce soldiers’ performance and mission success. Performance has been improved by technologies that make use of integrated means of information transfer, but there remains an increase in commanders’ workload and information processing demands. Most of the communication between commanders and their soldiers is handled by audio and visual devices. Less common is the use of tactile interfaces. The tactile modality allows a fast, intuitive, secured, and silent channel of communication. The main goal of the current study was to determine soldiers’ requirements and needs and based on those establish the characteristics of an experimental infrastructure for future experiments to test the efficiency of tactile interfaces in operational settings. To this end, questionnaires were distributed among infantry officers of the Israel Defense Forces (IDF). Analysis of the collected data provided insights into soldiers’ view of the tactile display usage in the battlefield. The results of this study lay the foundations for further research and development of an effective tactile channel to be used by soldiers in operational environments.

Thermoelectric Tactile Display Based on the Thermal Grill Illusion

Among the challenges of haptic displays is the objective of creating a tactile language. Tactile language is used as a substitute to visual and auditory languages when either of the modalities is overloaded or impaired. Haptic displays have been implemented using a variety of technologies to stimulate different tactile sensations such as pressure, vibration and temperature. In this work, we present a novel implementation of a thermal sensation known as the Thermal Grill Illusion as the basis of a tactile language. A designated system, the Thermoelectric Tactile Display, was developed to generate Thermal Grill Illusion based stimuli. The usability of this type of display is being evaluated.