P. A. HancockPh.D
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Publications by P. A. Hancock (bibliography)
» 1993 «
Hancock, P. A. and Chignell, M. H. (1993): Adaptive Function Allocation by Intelligent Interfaces. In: Gray, Wayne D., Hefley, William and Murray, Dianne (eds.) International Workshop on Intelligent User Interfaces 1993 January 4-7, 1993, Orlando, Florida, USA. pp. 227-229. Available online
“Intelligent interfaces act as translational intermediaries between humans and machines while themselves representing a third component in the human-interface-machine triad. They seek to maximize the collaborative capabilities of human and machine through the communication of mutual queries and actions in symbols best suited to the respective entity involved. This triad is directed to the achievement of a range of external goals. Attainment of such goals is best served by the enhancement of mutual adaptive capability of the individual components of the human-interface-machine triad and of the triad itself as a supraordinate unit. Within collective action, the question of who does what, when and with whom is best seen as a problem in adaptive allocation. This question is itself a subset of the general problem of function allocation which is arguably the foundation of human-machine interaction. This work advocates modular customization of the intelligent interface as a solution to the impasse that derives from previous and failed descriptive approaches to the allocation question.”
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Arthur, E. J., Hancock, P. A. and Chrysler, S. T. (1993): Spatial Orientation in Real and Virtual Worlds. In: Proceedings of the Human Factors and Ergonomics Society 37th Annual Meeting 1993. pp. 328-332.
“Virtual environments promise an almost limitless vista of expansion for human capabilities. They are being touted as the interface of the future and have begun to generate an expectation of a revolution in human-computer interaction greater than any seen to date. Like much hyperbole that cascades around innovative technology, little is based in knowledge while much is based on expectation or sheer speculation. In previous work, we have examined some of the basic human factors questions about usability. Here we specifically examine the ability to reproduce a complex spatial layout of objects having experienced them under a variety of viewing conditions. Subjects teamed the spatial layout of nine common objects arranged on a flat plane. Viewing conditions consisted of free binocular virtual, free binocular real, and monocular real. The first two allowed active exploration of the environment while the latter condition allowed only a single viewpoint. The dependent variables were mapping accuracy and triadic comparisons of relative inter-object distances. Mapping results showed a significant effect of viewing condition, where in contrast to expectations the single eye was superior to the virtual and real binocular conditions. Results for the triadic comparisons showed a significant interaction of gender by viewing condition. The spatial representation formed by using virtual reality appears equivalent to that of the representation with the actual objects. The are a number of implications of these data with respect to interface design, in particular the question of potential information overload in virtual interfaces.”
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» 1992 «
Smith, K. and Hancock, P. A. (1992): Managing Risk Under Time Stress. In: Proceedings of the Human Factors Society 36th Annual Meeting 1992. pp. 1019-1023.
“The evolution of automated and semi-automated systems is rendering continuous regulation relatively obsolete, leaving periodic "management" interventions as the main way in which operators exercise control. Consequently, the human is now more frequently required to respond in uncertain, unusual, or "emergency" conditions. Such circumstances connote high stress environments. Consequently, the research reported here investigates expertise at decision making under stress. The source of stress is ubiquitous in occurrence, namely time pressure. We present a process model that explains and predicts the decision behavior of skilled operators as they manage risk under time stress. The model identifies three components of decision making, (1) attention, (2) assessment, and (3) intervention. Attention (1) scans widely among information displays and focuses action narrowly upon one of three procedures for (2) assessing the attended information. Separate procedures assess ({alpha}) the risks posed by the environment, ({beta}) risks generated by interacting with the environment, and ({gamma}) uncertainty about those risks. The uniquely appropriate intervention (3) is selected by a small set of rules that match heuristically the assessments of risk and uncertainty to a short list of alternative actions. The model is validated with respect to the operation of skilled operators in the domain of currency exchange. In comparing performance versus simulation data, the model identifies the one procedure that resists automation -- the assessment of risks posed by the environment. This assessment involves causal arguments that often rely upon extensive domain knowledge. In contrast, attention to displays, heuristic matching, and the procedures for assessing uncertainty and the risk of interaction can be delegated to an automated decision support system. This result has clear implications for the design of systems to support skilled decision making under emergency conditions: decision support systems for dynamic environments like currency trading must notify the operator of the occurrence of system parameters that require assessments of environmental risk and incorporate these assessments into automated procedures that recommend appropriate interventions.”
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Caird, J. K. and Hancock, P. A. (1992): Perception of Oncoming Vehicle Time-to-Arrival. In: Proceedings of the Human Factors Society 36th Annual Meeting 1992. pp. 1378-1382.
“An experiment was conducted in a fixed-base driving simulator which manipulated the time-to-arrival (T{sub:a}) of an oncoming vehicle, the viewing distance to that vehicle and the type of oncoming vehicle to determine the perceptual basis for a left-turn decision. Forty-eight participants were randomly assigned to a group where either a motorcycle, a compact car, a full-size car, or delivery truck represented the oncoming vehicle. There were an equal number of participants of each gender in the four groups. As T{sub:a} was increased, underestimation of vehicle arrival time also increased. Significant main effects were found for T{sub:a}, gender of participants, vehicle type, and viewing distance, and for interactions for gender x T{sub:a} and gender x vehicle type. Males and females differed in their accuracy of judgments for vehicle types, where males were more accurate in estimating the arrival of delivery vans and motorcycles than their female peers. The pattern of results for the size of the approach vehicle were consistent with a margin-of-safety explanation which argues that driver underestimation of the arrival times of larger vehicles generally allows larger margins-of-safety than for smaller vehicles. The importance of these findings for the development of advanced in-vehicle collision avoidance and warning systems is briefly considered.”
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» 1991 «
Hancock, P. A., Caird, J. K., Shekhar, S. and Vercruyssen, M. (1991): Factors Influencing Drivers' Left Turn Decisions. In: Proceedings of the Human Factors Society 35th Annual Meeting 1991. pp. 1139-1143.
Caird, J. K. and Hancock, P. A. (1991): Perceived Spatial Layout of a Simulated Scene as a Function of Experience. In: Proceedings of the Human Factors Society 35th Annual Meeting 1991. pp. 1447-1451.
“A critical question in simulation is the degree of correspondence or alignment between what is seen in a generated graphics world and it's intended actual physical structure. An allied concern, is the role of perceptual experience as a potential influence on this perceived spatial layout. The present experiment examined the potential for these perceived distortions. Eight observers estimated the location of nine object locations embedded in a graphical scene of a traffic intersection. Participants were asked to judge the relative and absolute distances between objects in the display. Half the subjects viewed the intersection after driving for thirty minutes through the simulated traffic world while the remaining participants did not receive any prior experience. A multidimensional scaling analysis revealed differences between simulator and no simulator experience groups for absolute and relative 3-D solutions. Scaled representations of actual and perceived spaces are discussed in the framework of a model of perceived spatial layout and with respect to human factors issues in the use of both simulated and virtual worlds.”
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» 1990 «
Cann, Michael T., Vercruyssen, Max and Hancock, P. A. (1990): Age and the Elderly Internal Clock: Further Evidence for a Fundamentally Slowed CNS. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 158-162.
Fozard, James L., Vercruyssen, Max, Reynolds, Sara L. and Hancock, P. A. (1990): Longitudinal Analysis of Age-Related Slowing: BLSA Reaction Time Data. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 163-167.
Moray, Neville, Hart, Sandra G., Hancock, P. A., Kramer, Arthur F., Strayer, David L., Wickens, Christopher D., Segal, Leon, Raby, Mireille, Dessouky, Mohamed, Sanderson, Penelope and James, Jeffrey M. (1990): The Human Factors of Strategic Behavior. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 596-597.
Hancock, P. A., Chignell, M. H. and Vercruyssen, M. (1990): Predicting the Effects of Stress on Performance. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 1081-1085.
Caird, J. K., Hancock, P. A., Wade, M. G. and Vercruyssen, M. (1990): Workload and Strategic Adaptation Under Transformations on Visual-Coordinative Mappings. In: D., Woods, and E., Roth, (eds.) Proceedings of the Human Factors Society 34th Annual Meeting 1990, Santa Monica, USA. pp. 1290-1294.
» 1989 «
Vercruyssen, Max, Cann, Michael T. and Hancock, P. A. (1989): Gender Differences in Posture Effects on Cognition. In: Proceedings of the Human Factors Society 33rd Annual Meeting 1989. pp. 896-900.
“To investigate the effects of body posture on reaction time, 28 healthy university students (14 male and 14 female) served as subjects performing four-choice visual reaction tasks while sitting and standing, with intersession practice and complete duplication of the study on a second day. Intratask manipulations were stimulus degradation, stimulus-response compatibility, and the response-stimulus interval (foreperiod uncertainty). Results showed main effects for all intratask variables and practice with interactions related to gender, posture, and degradation. Significant gender differences in the effects of posture and degradation were such that females had a slight advantage over males on tasks which emphasize early stages of processing. In general, it is concluded that the large disparity of findings within the gender-related psychomotor literature may be largely a function of methodological differences between studies. This investigation showed that experimental findings may vary according to the particular task used and the circumstances under which it was performed.”
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Wulf, Gabriele, Hancock, P. A. and Rahimi, Mansour (1989): Some Causes of Automobile-Motorcycle Collisions. In: Proceedings of the Human Factors Society 33rd Annual Meeting 1989. pp. 910-914.
“Motorcycles are overrepresented in fatal motor-vehicle accidents. In the attempt to reduce the frequency of automobile-motorcycle collisions, numerous studies have manipulated motorcycle and motorcyclist characteristics to enhance conspicuity. In this paper, we review of studies that have examined the effectiveness of these measures. Furthermore, we identify factors yet to be considered in the empirical research in this area that may contribute to collisions between cars and motorcycles. These include information-processing failures at the identification and decision stage, as well as relatively stable and volatile factors potentially responsible for different information-processing failures.”
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Hancock, P. A., Wulf, Gabriele, Thom, David R. and Fassnacht, Peter (1989): Contrasting Driver Behavior during Turns and Straight Driving. In: Proceedings of the Human Factors Society 33rd Annual Meeting 1989. pp. 918-922.
“In automobile-motorcycle collisions, one particular configuration clearly stands out above all others. This dominant case sees the automobile driver turn left across the right-of-way of the on-coming motorcyclist. Our attempts to understand this particular accident have focused upon the actions of the driver. In the results of the experiment reported here, it is clear that turning involves a higher probability of structural interference to visual information processing and increase in mental load compared to straight driving. These effects are implicated in increased detection failure. The outcome of detection failure is radically different for left versus right-turns. In the former case, a turn is made across the face of on-coming traffic compared to the latter, more benign condition where no traffic conflict is liable to be experienced. The implications of these findings for enhancing motorcycle conspicuity are examined.”
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Hancock, P. A., Chignell, M. H., Vercruyssen, M. and Denhoff, M. (1989): Experimental Evaluations of a Model of Mental Workload. In: Proceedings of the Human Factors Society 33rd Annual Meeting 1989. pp. 1233-1237.
“The present experiments were designed to test predictions from a model of mental workload. The model predicts non-linear increases in mental workload as perceived distance from a task goal grows and effective time for action is reduced. Diminuation of mental workload is achieved by application of effort which brings the task goal into the region of acceptable time/distance constraints for successful resolution. Two experiments are reported which tested these assertions using the timepools performance task. Timepools is unique as a performance task in that it generates a spatial representation of a shrinking temporal target. The independent effects of path length, i.e., the number of sequential targets to be acquired, and shrink rate, i.e., the collapse time during which the circle is halved in are, may be assessed using performance variables such as reaction time (RT), movement time (MT), error rate (E), and the subjective perception of workload. Dat from Experiment 1, indicate systematic effects for task related factors across performance and workload measures, although such a pattern was not isomorphically mapped to the a priori assumed difficulty of the task. In Experiment 2, shrink rate and path length had independent effect on RT and MT respectively, which were reflected in components of the individual workload scales. The ramifications with respect to the model are elaborated.”
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Hancock, P. A., Robinson, M. A., Chu, A. L., Hansen, D. R., Vercruyssen, M., Grose, E. and Fisk, A. D. (1989): The Effects of Practice on Tracking and Subjective Workload. In: Proceedings of the Human Factors Society 33rd Annual Meeting 1989. pp. 1310-1314.
“Six college-age male subjects performed one hundred, two-minute trials on a second-order tracking task. After each trial, subjects estimated perceived workload using both the NASA TLX and SWAT workload assessment procedures. Results confirmed an expected performance improvement on the tracking task which followed traditional learning curves within the performance of each individual. Perceived workload also decreased for both scales across trials. While performance variability significantly decreased across trials, workload variability remained constant. One month later, the same subjects returned to complete the second experiment in the sequence which was a retention replication of the first experiment. Results replicated those for the first experiment except that both performance error and workload were at reduced overall levels. Results in general affirm a parallel workload reduction with performance improvement, an observation consistent with a resource-based view of automaticity.”
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» 1988 «
Vercruyssen, Max, Cann, Michael T., McDowd, Joan M., Birren, James E., Carlton, Barbara L., Burton, Jane and Hancock, P. A. (1988): Effects of Age, Gender, Activation, Stimulus Degradation and Practice on Attention and Visual Choice Reaction Time. In: Proceedings of the Human Factors Society 32nd Annual Meeting 1988. pp. 203-207.
“This paper presents research conducted by the authors and others investigating the interaction of a variety of variables which are presumed to affect reaction time in hopes of obtaining much needed information on factors influencing age effects on attention and information processing. Reported is progress to date on an experiment which shows that the effects of age on central nervous system speed, as measured by visual choice reaction time, depends on many factors, including the gender, neural activation level, and skill of the subject as well as the stimulus quality and type of reaction task employed.”
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Hancock, P. A., Rodenburg, G. J., Mathews, W. D. and Vercruyssen, M. (1988): Estimation of Duration and Mental Workload at Differing Times of Day by Males and Females. In: Proceedings of the Human Factors Society 32nd Annual Meeting 1988. pp. 857-861.
“Two experiments are reported which investigated whether male and female operator duration estimation and subjective workload followed conventional circadian fluctuation. In the first experiment, twenty-four subjects performed a filled time-estimation task in a constant blacked-out, noise-reduced environment at 0800, 1200, 1600 and 2000h. In the second experiment, twelve subjects performed an unfilled time estimation task in similar conditions at 0900, 1400, and 1900h. At the termination of all experimental sessions, participants completed the NASA TLX workload assessment questionnaire as a measure of perceived mental workload. Results indicated that while physiological response followed an expected pattern, estimations of duration and subjective perception of workload showed no significant effects for time-of-day. In each of the experiments, however, there were significant differences in duration estimates and mental workload response depending upon the gender of the participant. Results are taken to support the assertion that subjective workload is responsive largely to task-related factors and indicates the important differences that may be expected due to operator gender.”
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Mihaly, T., Hancock, P. A., Vercruyssen, M. and Rahimi, M. (1988): Time Estimation Performance Before, During and After Physical Activity. In: Proceedings of the Human Factors Society 32nd Annual Meeting 1988. pp. 985-989.
“An experiment is reported which evaluated performance on a 10-sec time interval estimation task before, during and after physical work on cycle ergometer at intensities of 30 and 60% VO{sub:2}max, as scaled to the individual subject. Results from the eleven subjects tested indicate a significant increase in variability of estimates during exercise compared to non-exercise phases. Such a trend was also seen in the mean of estimates, where subjects significantly underestimated the target interval (10 seconds) during exercise. Subjects also performed more accurately with information feedback than without knowledge of results, but they were still not able to overcome the effects of exercise. As suggested by the experimental findings, decreased estimation accuracy and increased variability can be expected during physical work and is part of a body of evidence which indicates that exercise and its severity has a substantive impact on perceptual and cognitive performance.”
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Mar 22nd, 2010
Changes to this page (author)
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