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Sensory feedback, which can be presented in different modalities -single and combined, aids task performance in human-robotic interaction (HRI). However, combining feedback modalities does not always lead to optimal performance. Indeed, it is not known how feedback modalities affect operator performance under stress. Furthermore, there is limited information on how feedback affects neural processes differently for males and females and under stress. This is a critical gap in the literature, particularly in the domain of surgical robotics, where surgeons are under challenging socio-technical environments that burden them physiologically. In the present study, we posited operator performance as the summation of task performance and neurophysiological cost of maintaining that performance. In a within-subject design, we used functional near-infrared spectroscopy to assess cerebral activations of 12 participants who underwent a 3D manipulation task within a virtual environment with concurrent feedback (visual and visual + haptic) in the presence and absence of a cognitive stressor. Cognitive stress was induced with the serial-7 subtraction test. We found that while task performance was higher with visual than visual + haptic feedback, it degraded under stress. The two feedback modalities were found to be associated with varying neural activities and neural efficiencies, and these were stress-and genderdependent. Our findings engender further investigation into effectiveness of feedback modalities on males and females under stressful conditions in HRI.

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Office workers are at high-risk for work-related musculoskeletal disorders (WMSDs), which can inhibit productivity and perceived comfort through associated disorders (Piligian et al, 2000). An increase in WMSDs has created a demand for ergonomic office interventions. Recent ergonomic advancements have focused on dynamic office furniture that aim to promote chairs featuring structural designs (Ellegast et al, 2012). Dynamic office furniture lacking a range of specific and modifiable adjustments can lead to adverse outcomes, such as nerve compression, resulting in perceived discomfort and increased risk of musculoskeletal disorders (Groenesteijn et al, 2009; Legg et al, 2002). However, there is limited research regarding the relationship of posture changes and the effects on perceived comfort and task performance. The objective of the study was to explore the relationship between perceived comfort, productivity, postural changes, and adjustability in chairs with varying degrees of adjustability. The study consisted of 44 participants (54.5% males, 22.8 (2.89) years) attending three different days, working together in teams of 2-3, to complete a 3-hour simulated office task related to construction science. Tasks required team collaboration to evaluate construction bids, develop plan of actions, and present conclusions to each task. To determine the ergonomic impact of office furniture on team creativity and productivity on the design project, two different types of chairs were employed that varied in the level of user involvement for chair adjustments – no involvement without adjustment and high involvement with adjustment, each presented on separate days. Subjective surveys were used at the end of every session to evaluate the chair used in that session that determined individual satisfaction, usability, and perceived discomfort levels. Continuous video obtained during the sessions were analyzed to obtain the number of postural changes (e.g., bending from side to side, shoulders or back ‘drooping’), chair adjustments made, unintended jerks, and chair switches throughout each time period (for a total of 3 time periods) on each day. Performance on the simulated construction science tasks were assessed using a predetermined rubric that included components such as document completion, completed summaries, and presentations to obtain a total performance score. Reported here are preliminary findings from the video analyses and discomfort surveys. A 2-chair x 3-time repeated measures analysis of variance (ANOVA) on postural change over time revealed that postural changes on the chair associated with no involvement without adjustment was higher than that of high involvement with adjustment, however this was only seen in times 1 and 2. This implies that the benefit of adjustments are likely lost over time. Separate one-way ANOVAs were performed on discomfort scores to test the effects of the two chairs. Overall, perceived discomfort across different body regions did not differ between chairs. It is likely that more postural changes were needed to maintain initial comfort levels in the no involvement no adjustment chair studied and were necessary to minimize discomfort. Preliminary findings obtained here will help identify the extent to which postural deviations affect team productivity and responses on discomfort and strain.