Robert Henning
Associate Professor of Psychology
Department of Psychology
406 Babbidge Road
University of Connecticut
Storrs, CT 06269-1020
PHONE: (860) 486-5918
FAX: (860) 486-2760
E-MAIL: Robert.Henning@uconn.edu

ACADEMIC TRAINING

• B.S. Psychology, 1974, University of Wisconsin-Madison
• M.S. Biomedical Engineering, 1980, University of Wisconsin-Madison
• Ph.D. Industrial Engineering, 1986, University of Wisconsin-Madison

POST-DOCTORAL TRAINING

Post doctoral fellow, National Research Council and National Institute for Safety and Health (NIOSH) (1986-1989)

Research Area: The effects of work pattern, social interaction, and brief rest pauses on performance and well-being during computer-mediated work.

PROFESSIONAL CERTIFICATION

• Board-Certified Human Factors Professional (CHFP, effective 1994)

PROFESSIONAL AFFILIATIONS

• Member, Human Factors and Ergonomics Society
• Secretary/Treasurer and President-elect, Psychophysiology in Ergonomics (a technical group of the International Ergonomics Association)
• Member, Society for Psychophysiological Research

OVERVIEW OF RESEARCH

My research interests can be divided into three areas:

1. work/rest schedules for video display terminal (VDT) operators
2. the psychophysiology of human-computer interaction
3. studies of work coordination

Cybernetic theory as developed by Smith & Smith (1987) focuses on how individuals simultaneously control the environment, sensory input, and internal physiological state. Behavior is understood as a continuous, self-regulated control process that is critically dependent on self-generated feedback information. Performance variability in human-machine systems, for example, can be caused by a time delay between operator input and system response that perturbs feedback control. Perturbed feedback is a human factors problem that not only causes decrements in performance, it also has a negative impact on well-being by impairing self-regulation of behavior. The coordination of work activities by multiple coworkers also depends on feedback control but involves more complicated modes of control.

Work/Rest Schedules for VDT Operators

Reports of health problems and user dissatisfaction with continuous, video display terminal (VDT) work continue to be widespread in the fastest growing segment of the workforce. From a cybernetics perspective, human factors design flaws that prevent or limit self-regulation of work behavior are the source of many of these problems. One specific example is the limited opportunity to control rest break behavior during some forms of computer-mediated work.

In my doctoral research, I hypothesized that the length of user-terminated rest breaks could serve as an objective measure of work load but found that the length of rest breaks was also influenced by other factors (Henning, 1987). In research conducted at the National Institute for Occupational Safety and Health (NIOSH) as a National Research Council post-doctoral trainee, it was determined that professional VDT operators usually terminated rest breaks before full recovery had occurred (Henning et al., 1989), a result that helped guide subsequent NIOSH research on rest break schedules for VDT operators. At UConn, field research showed that short rest breaks at 15-minute intervals benefitted the productivity and well-being of VDT operators at one of two work sites (Henning et al., 1996). The lack of beneficial effects at one work site suggested that the effectiveness of short rest breaks may depend on task integration.

Based on the mixed results in the field study and the limited positive impact of added rest breaks in the NIOSH laboratory studies, I began questioning the assumption that short rest breaks should be administered to VDT operators on a rigid schedule and in a machine-paced manner. A series of laboratory experiments to test alternative rest break administration systems that were more consistent with cybernetic principles of self-regulation were then conducted. The effectiveness of each system was evaluated through detailed measurements of keystroke performance, physiological response measures, and subjective ratings of mood and musculoskeletal discomfort.

The first alternative rest break system was compensatory in nature because rest breaks were only administered by a computer if VDT users failed to take an adequate number of discretionary rest breaks. One presumed advantage of discretionary rest breaks over machine-administered breaks is that discretionary rest breaks are less disruptive to overall task performance. However, this compensatory rest break system had only limited success in promoting discretionary rest break behavior (Henning et al., 1994). A second alternative rest break system provided continuous feedback information to VDT users about their discretionary rest break behavior. As predicted by cybernetic theory, VDT users were more successful in self-managing discretionary rest breaks when this feedback information was available (Henning et al., 1996), and feedback information presented in a task-integrated format could be used more effectively by VDT users.

In a new line of research, methods of promoting social control of rest break behavior during computer-mediated work are being explored. This research anticipates a time when VDT users will be engaged in computer-supported cooperative work over extended periods. In the first experiments, two VDT users were asked to jointly manage their discretionary rest break behavior while performing a cooperative word processing task (Henning et al., 1997). Using principles from cybernetic theory, both parallel and serial modes of social control were tested. For example, in some cases feedback about joint rest break behavior were provided to only one participant.

Psychophysiology of Human-computer Interaction

According to cybernetic theory, efficiency in behavior is determined by how well an individual can integrate control over work behavior and internal physiological state. In early comparisons of self-paced versus machine-paced work (Henning, 1987), I adapted an analysis technique developed by Porges et al. (1980) to score synchronization relationships between the work rhythm and the breathing rhythm as an indicator of control compliance and behavioral efficiency. This line of research was expanded at NIOSH to include work-cardiac synchronization and also work-cardiac-breathing synchronization. Work-physiological synchronization was examined in a self-paced data-entry task through systematic manipulations in task design that induced a wide range of work rhythms. Synchronization was found to be predictive of both worker well-being (Henning et al., 1992) and performance (Henning & Sauter, 1996). This study also demonstrated that worker control over the work rhythm of a self-paced task may, in some cases, be quite limited.

Some of the techniques for scoring work-physiological synchronization described above was presented at special symposiums at both the 1995 and 2000 annual meetings of the Human Factors and Ergonomics Society.

Studies of Work Coordination

I have a long-standing interest in developing objective measures of work coordination based on psychophysiology, with the goal of applying these measures to the design and analysis of sociotechnical systems.

At NIOSH, a laboratory study of professional VDT operators examined the effects of social interaction on productivity and wellbeing (Henning et al., 1988). Three exploratory studies of work coordination have been conducted at UConn, In the first study, VDT users performed a computer-based task that involved a rudimentary form of work coordination, namely simple turn-taking. Feedback about coworker typing behavior was time-delayed in some conditions of the experiment to disrupt work coordination. Synchronization analysis techniques developed in my earlier studies were applied to the study of social psychophysiology in this experiment. Breathing patterns among VDT users were less synchronous in the delayed feedback conditions, providing evidence that motor-sensory control may become integrated during work coordination in the manner predicted by cybernetic theory (Henning, 1992). More recently, voice transmissions were time-delayed to perturb work coordination during a two-person word processing task. Although performance was significantly degraded by this time delay, VDT users were unaware of system limitations and only reported increased fatigue (Braun & Henning, 1996). These results suggest that human factors design flaws in sociotechnical systems may seriously impair work coordination while going undetected by workers performing joint tasks. Preliminary findings of synchronization relationships in this experiment and one other experiment were recently reported at a scientific conference (Henning, McFadden, & Bopp, 1996).

Work coordination and social psychophysiology will be dominant themes in my research over the next 5-10 years. To this end, my laboratory has been outfitted for four-person experiments on work coordination. The cybernetics of sociotechnical systems is also the theme of a co-authored paper (Smith et al., 1995). MOre recently, we have been able to demonstrate a close relationship between social psychophysiology and team work effectiveness (Henning et al., 2001). This line of research has also examined how force feedback can be used to promote teamwork in a continuous control task (Glynn et al., 2002). One encouraging sign in the human factors literature is the growing interest in topics like "situation awareness" in sociotechnical systems. A recognized need for objective, process-oriented measures of work coordination and social interaction is anticipated.

Representative Scholarly Papers (grouped by topic area and in chronological order)

Henning, R. A. (1987). Worker-terminated microbreaks & perceptual-motor performance. Proceedings: Fourth Mid-Central Ergonomics/Human Factors Conference, 374-380.

Henning, R. A., Sauter, S. L., Salvendy, G., & Krieg, E. F., Jr. (1989). Microbreak length, performance, & stress in a data entry task. Ergonomics, 32(7), 855-864.

Henning, R.A., Kissel, G.V, & Maynard, D.C. (1994). Compensatory rest breaks for VDT operators. International Journal of Industrial Ergonomics, 14, 243-249.

Henning, R.A. Callaghan, E.A., Ortega, A.M., Kissel, G.V., Guttman, J.I., & Braun, H.A. (1996). Continuous feedback to promote self-management of rest breaks during computer use. International Journal of Industrial Ergonomics, 18, 71-82.

Henning, R.A., Jacques, P., Kissel, G.V., Sullivan, A.B., & Alteras-Webb, S.M. (1997). Frequent, short breaks from computer work: effects on productivity and well-being at two field sites. Ergonomics, 40 (1), 78-91.

Henning, R.A., Bopp, M.I., Tucker, K.M., Knoph, R.D., and Ahlgren, J. (1997). Team-managed rest breaks during computersupported cooperative work. International Journal of Industrial Ergonomics, 20, 19-29.

Henning, R. A. (1987). Work rhythm & breathing rhythm in a perceptual-motor task: the effects of synchronization on performance. Proceedings: 31st Annual Meeting of the Human Factors Society, 2, 1336-1340.

Henning, R.A., Sauter, S.L., & Krieg, E.F., Jr. (1992). Work rhythm & physiological rhythms in repetitive computer work: Effects of synchronization on well-being. International Journal on Human Computer Interaction, 4 (3), 233-243.

Henning, R.A. (symposium chair) (1995). Evaluation of work schedules using psychophysiological measures. Proceedings: 39th Annual Meeting of the Human Factors & Ergonomics Society.

Henning, R.A., and Sauter, S.L. (1996). Work- physiological synchronization as a determinant of performance in repetitive computer work. Biological Psychology, 42, 269-286.

Henning, R. A., Krieg, E. F., Jr., & Sauter, S. L. (1988). Effects of social interaction on performance & mood state during computer-based data entry work. Proceedings: 32nd Annual Meeting of the Human Factors Society, 1, 506-510.

Henning, R.A. (1992). Psychosocial dynamics during a cooperative computer-based task. Proceedings: 36th Annual Meeting of the Human Factors & Ergonomics Society, October 12-16, Atlanta, Georgia.

Smith, T.J., Henning, R.A., & Smith, K.U. (1995). Performance ofhybrid automated systems - a social cybernetic analysis. International Journal of Human Factors in Manufacturing, 5(1), 29-51.

Braun, H.A., & Henning, R.A. (1996). Performance effects of delayed social feedback during computer-supported cooperative work. Meeting of the American Society of Ergonomics Systems Engineering. Madison, Wisconsin, September 13-14.

Henning, R. A., Boucsein, W., and Gil, M. C. (2001). Social-physiological compliance as a determinant of team performance. International Journal of Psychophysiology, 40, 221-232.

Glynn, S., Fekieta, R., & Henning, R. A. (2001). Use of force-feedback joysticks to promote teamwork in virtual teleoperation. Proc. 45th Annual Meeting of the Human Factors and Ergonomics society, October 8-12, 2001, Minneapolis/St. Paul, MN, pp. 1911-1915.

Related References (not co-authored by Henning)

Porges, S.W., Bohrer, R.E., Cheung, M.N., Drasgow, F., McCabe, P.M., & Keren, G. (1980). New time series statistic for detecting rhythmic co-occurrence in the frequency domain: the weighted coherence and its applications to psychophysiological research. Psychological Bulletin, 88, 3, 580-587.

Smith, T.J., & Smith, K.U. (1987). Feedback control mechanisms of human behavior. In: G. Salvendy (Ed.), Handbook of Human Factors. New York: Wiley, pp. 251-293.