Postcompletion Error Research Articles

Human Error as an Emergent Property of Action Selection and Task Place-Holding.

A computational process model could explain how the dynamic interaction of human cognitive mechanisms produces each of multiple error types. With increasing capability and complexity of technological systems, the potential severity of consequences of human error is magnified. Interruption greatly increases people's error rates, as does the presence of other information to maintain in an active state. The model executed as a software-instantiated Monte Carlo simulation. It drew on theoretical constructs such as associative spreading activation for prospective memory, explicit rehearsal strategies as a deliberate cognitive operation to aid retrospective memory, and decay. The model replicated the 30% effect of interruptions on postcompletion error in Ratwani and Trafton's Stock Trader task, the 45% interaction effect on postcompletion error of working memory capacity and working memory load from Byrne and Bovair's Phaser Task, as well as the 5% perseveration and 3% omission effects of interruption from the UNRAVEL Task. Error classes including perseveration, omission, and postcompletion error fall naturally out of the theory. The model explains post-interruption error in terms of task state representation and priming for recall of subsequent steps. Its performance suggests that task environments providing more cues to current task state will mitigate error caused by interruption. For example, interfaces could provide labeled progress indicators or facilities for operators to quickly write notes about their task states when interrupted.

An analysis of aircraft maintenance incidents using psychological and cognitive engineering knowledge

The aim of the current analysis is to complement existing studies of aircraft maintenance incidents by providing finer and more detailed explanations for their causes in terms of task and error types. A total of 109 aircraft maintenance incidents were analyzed with respect to knowledge and concepts from psychology and cognitive engineering. The skill, rule and knowledge-based framework by Rasmussen (1983) was used to identify the main task types involved in the incidents. Error types such as post-completion error, prospective memory failure and data-entry error were used as part of the analysis. System usability and the occurrence of interruptions, distractions and multitasking were also adopted as important factors in the analysis. Results suggest that more than 60% of the incidents involved rule-based performance. Almost 50% of the rule-based incidents can be explained in terms of the errors types and factors identified. This analysis provides a starting point for practitioners to discuss aircraft maintenance incidents using theoretically grounded concepts.

Action Selection and Human Error in Routine Procedures

We discuss a computational process model of action selection in routine procedures. The model explains several types of human error—omissions, perseverations, and postcompletion error (PCE)— as natural consequences of its action selection mechanisms. Those mechanisms include associative spreading activation for prospective memory and explicit rehearsal strategies for retrospective memory. The model fits empirical data from multiple tasks and from multiple labs.

A Behavioral Intervention for Reducing Postcompletion Errors in a Safety-Critical System.

We investigated the effectiveness of a theoretically motivated intervention at reducing procedural errors in train yard operations, where making these errors could be costly or life-threatening. A widespread and persistent memory error that people commit on a daily basis is the postcompletion error (PCE), that is, forgetting to complete the final step of a procedural task in which the final step occurs after completion of the task goal. PCEs occur in the railroad industry when a locomotive conductor changes the direction of a rail switch but fails to report this change. This particular error could contribute to unsafe conditions as another train traveling on the same track could derail. Although training can help reduce some of the factors leading to unsafe conditions on the rail, research has demonstrated that PCEs are different from other errors of omission in that they cannot be eliminated through training, which makes them a difficult problem to address. Twenty-eight undergraduates completed train yard tasks within a mid-fidelity simulator used in commercial rail operations for training. Each participant received the behavioral intervention in one block and no intervention in another. Specifically, participants were required to perform an additional task designed to remind participants of the postcompletion step. Our intervention significantly reduced PCE rates in the context of train yard operations, on average by 65%. We discuss implications of the effectiveness of our intervention at reducing train yard accidents and how this outcome can contribute to the literature on the cause of PCEs. In cases such as the railroad industry, where redesigning technology is prohibitive, our behavioral intervention is an effective alternative for significantly reducing PCEs.

Simple prompts reduce inadvertent energy consumption from lighting in office buildings

Building designs regularly fail to achieve the anticipated levels of in-use energy consumption. The interaction of occupants with building controls is often cited as a key factor behind this discrepancy. This paper examines whether one factor in inadvertent energy consumption might be the appearance of post-completion errors (when an intended action is not taken because a primary goal has already been accomplished) in occupants' interactions with building controls. Post-completion errors have been widely studied in human-computer interaction but the concept has not previously been applied to the interaction of occupants with building controls. Two experiments were carried out to examine the effect of incorporating two different types of simple prompt to reduce post-completion error in the use of light switches in office meeting rooms. Results showed that the prompts were effective and that occupants switched off lights when leaving the room more often when presented with a normative prompt than with a standard injunction. Additionally, an over reliance on PIR sensors to turn off lights after meetings was observed, which reduced their intended energy savings. We conclude that achieving low carbon buildings in practice is not solely a technological issue and that application of user-models from human-computer interaction will encourage appropriate occupant interaction with building controls and help reduce inadvertent energy consumption.

A Real-Time Eye Tracking System for Predicting and Preventing Postcompletion Errors

Procedural errors occur despite the user having the correct knowledge of how to perform a particular task. Previous research has mostly focused on preventing these errors by redesigning tasks to eliminate error prone steps. A different method of preventing errors, specifically postcompletion errors (e.g., forgetting to retrieve the original document from a photocopier), has been proposed by Ratwani, McCurry, and Trafton (2008), which uses theoretically motivated eye movement measures to predict when a user will make an error. The predictive value of the eye-movement-based model was examined and validated on two different tasks using a receiver-operating characteristic analysis. A real-time eye-tracking postcompletion error prediction system was then developed and tested; results demonstrate that the real-time system successfully predicts and prevents postcompletion errors before a user commits the error.

The Effect of Interruptions and Global Placekeeping on Postcompletion Error Rates

A postcompletion error occurs when the final step of a task is omitted because the main goal of the task is thought to be completed (Byrne & Bovair, 1997). Postcompletion errors are more likely to occur after interruptions (Ratwani, McCurry & Trafton, 2008). Global placekeeping cues (Gray, 2000) allow a user to track their progress in a task and may be a method for reducing the rate of postcompletion errors. A computer-based procedural task with a postcompletion step was used in this experiment to determine how the interaction of global placekeeping cues with interruptions would affect postcompletion errors. These results suggest that global placekeeping cues reduce the postcompletion error rate after interruptions, but that global placekeeping does not completely eliminate postcompletion errors.

A generalized model for predicting postcompletion errors.

A postcompletion error is a type of procedural error that occurs after the main goal of a task has been accomplished. There is a strong theoretical foundation accounting for postcompletion errors (Altmann & Trafton, 2002; Byrne & Bovair, 1997). This theoretical foundation has been leveraged to develop a logistic regression model of postcompletion errors based on reaction time and eye movement measures (Ratwani, McCurry, & Trafton, 2008). This study further develops and extends this predictive model by (a) validating the model and the general set of predictors on a new task to test the robustness of the model, and (b) determining which specific theoretical components are most important to postcompletion error prediction.

The effect of interruptions on postcompletion and other procedural errors: An account based on the activation-based goal memory model.

A postcompletion error (PCE) is a specific kind of cognitive slip that involves omitting a final task step after the main goal of the task is accomplished. It is notoriously difficult to provoke (and hence study) slips under experimental conditions. In this paper, the authors present an experimental task paradigm that has been shown to be effective for studying PCEs in routine procedural tasks. Two studies were carried out to examine the effect of interruption position and task structure on the prevalence of PCEs. It was found that significantly more PCEs were obtained when an interruption occurred just before the PC step than when an interruption occurred at any other position in the task. The authors account for this effect in terms of Altmann and Trafton's activation-based goal memory model. The same interruption effect was obtained for some, but not all, other procedural errors; the authors discuss the nature of these errors and likely explanations for the differences.

Cue effectiveness in mitigating postcompletion errors in a routine procedural task

Postcompletion errors, which are omissions of actions required after the completion of a task's main goal, occur in a variety of everyday procedural tasks. Previous research has demonstrated the difficulty of reducing their frequency by means other than redesigning the task structure [Byrne, M.D., Davis, E.M., 2006. Task structure and postcompletion error in the execution of a routine procedure. Human Factors 48, 627–638]. Nevertheless, finding a successful strategy for mitigation of this type of error may uncover important mechanisms underlying interactive behavior. Two experiments were carried out to test visual cues for their ability to reduce the frequency of postcompletion errors in a computer-based routine procedural task. A cue that was visually salient, just-in-time, and meaningful entirely eliminated the error, whereas cues that were not as specific were ineffective. These results are beyond the predictive capability of extant error identification methods and common design guidelines but are consistent with the work of Altmann and Trafton [2002. Memory for goals: an activation-based model. Cognitive Science 26, 39–83] and Hollnagel [1993. Human Reliability Analysis, Context and Control. Academic Press, London]. Finally, a computational model developed in ACT-R is presented as a first step towards validation of the major findings from the two experiments.

Task Structure and Postcompletion Error in the Execution of a Routine Procedure

To replicate a successful laboratory slip-class error paradigm and, more importantly, to further understand the underlying causes of errors made in that paradigm. Routine procedural errors are facts of everyday life but have received limited controlled empirical study, despite the sometimes severe consequences associated with such errors. This research concerns one such error, postcompletion error (M. D. Byrne & S. Bovair, 1997), which is a lapse that occurs after the main goal of a task has been satisfied. In the two experiments conducted, participants were trained to criterion on a routine procedural task and were then brought back to the lab for a later session or sessions in which performance on task execution was measured. In the second experiment, a variety of motivational manipulations, retraining, and task redesign were compared. Experiment 1 demonstrated a substantial reduction of error rate generated by a simple design change (alteration of when feedback about goal completion occurred). Furthermore, the reduction in error rate came with no penalty in terms of overall speed of performance. Experiment 2 showed that this more appropriate design is superior to motivationally oriented interventions, retraining, and even midtask redesign. As in Experiment 1, Experiment 2 revealed no speed-accuracy tradeoff. These experiments provide evidence that controlled laboratory studies of slip-class errors can be meaningful and highlight the centrality of cognitive factors (particularly goal structure) in such errors. Potential applications include design of interfaces and their related procedures as well as error-mitigation techniques.

Memory for goals: an activation-based model

Goal-directed cognition is often discussed in terms of specialized memory structures like the “goal stack.” The goal-activation model presented here analyzes goal-directed cognition in terms of the general memory constructs of activation and associative priming. The model embodies three predictive constraints: (1) the interference level, which arises from residual memory for old goals; (1) the strengthening constraint, which makes predictions about time to encode a new goal; and (3) the priming constraint, which makes predictions about the role of cues in retrieving pending goals. These constraints are formulated algebraically and tested through simulation of latency and error data from the Tower of Hanoi, a means-ends puzzle that depends heavily on suspension and resumption of goals. Implications of the model for understanding intention superiority, postcompletion error, and effects of task interruption are discussed.

Memory for goals: an activation‐based model

AbstractGoal‐directed cognition is often discussed in terms of specialized memory structures like the “goal stack.” The goal‐activation model presented here analyzes goal‐directed cognition in terms of the general memory constructs of activation and associative priming. The model embodies three predictive constraints: (1) the interference level, which arises from residual memory for old goals; (1) the strengthening constraint, which makes predictions about time to encode a new goal; and (3) the priming constraint, which makes predictions about the role of cues in retrieving pending goals. These constraints are formulated algebraically and tested through simulation of latency and error data from the Tower of Hanoi, a means‐ends puzzle that depends heavily on suspension and resumption of goals. Implications of the model for understanding intention superiority, postcompletion error, and effects of task interruption are discussed.

A Working Memory Model of a Common Procedural Error

Systematic errors In performance are an important aspect of human behavior that have not received adequate explanation. One such systematic error is termed postcompletion error; a typical example is leaving one's card In the automatic teller after withdrawing cash. This type of error seems to occur when people have an extra step to perform in a procedure after the main goal has been satisfied. The fact that people frequently make this type of error, but do not make this error every time, may best be explained by considering the working memory load at the time the step is to be performed: The error is made when the load on working memory is high, but will not be made when the load is low. A model of performance In the task was constructed using Just and Carpenter's (1992) CAPS that predicted that high working memory load should be associated with postcompletion errors. Two experiments confirmed that such errors can be produced in a laboratory as well as a naturalistic setting, and that the conditions under which the CAPS model makes the error are consistent with the conditions under which the errors occur in the laboratory.

A working memory model of a common procedural error

Systematic errors In performance are an important aspect of human behavior that have not received adequate explanation. One such systematic error is termed postcompletion error; a typical example is leaving one's card In the automatic teller after withdrawing cash. This type of error seems to occur when people have an extra step to perform in a procedure after the main goal has been satisfied. The fact that people frequently make this type of error, but do not make this error every time, may best be explained by considering the working memory load at the time the step is to be performed: The error is made when the load on working memory is high, but will not be made when the load is low. A model of performance In the task was constructed using Just and Carpenter's (1992) CAPS that predicted that high working memory load should be associated with postcompletion errors. Two experiments confirmed that such errors can be produced in a laboratory as well as a naturalistic setting, and that the conditions under which the CAPS model makes the error are consistent with the conditions under which the errors occur in the laboratory.