Deborah A. Boehm-Davis

The effect of interruption duration and demand on resuming suspended goals.

The time to resume task goals after an interruption varied depending on the duration and cognitive demand of interruptions, as predicted by the memory for goals model (Altmann & Trafton, 2002). Three experiments using an interleaved tasks interruption paradigm showed that longer and more demanding interruptions led to longer resumption times in a hierarchical, interactive task. The resumption time profile for durations up to 1 min supported the role of decay in defining resumption costs, and the interaction between duration and demand supported the importance of goal rehearsal in mitigating decay. These findings supported the memory for goals model, and had practical implications for context where tasks are frequently interleaved such as office settings, driving, emergency rooms, and aircraft cockpits.

Recovering From Interruptions: Implications for Driver Distraction Research

This research adopted a model of goal activation to study the mechanisms underlying interrupted task performance. The effects of interruption timing, type of interruption, and age on task time and primary task resumption time were explored under conditions in which attention was switched back and forth between two tasks, much as when drivers shift attention between attending to the road and to an in-vehicle task. The timing of interruptions had a significant impact on task resumption times, indicating that the most costly time to interrupt task performance is during the middle of a task. However, this effect was overshadowed by age-related performance decrements for older participants. Interruptions that prevented strategic rehearsal of goals resulted in longer resumption times as compared with interruptions that allowed rehearsal. Actual or potential applications of this research include the design of in-vehicle device user interfaces, the timing of in-vehicle messages, and current metrics for assessing driver distraction.

Thinking graphically: Connecting vision and cognition during graph comprehension.

Task analytic theories of graph comprehension account for the perceptual and conceptual processes required to extract specific information from graphs. Comparatively, the processes underlying information integration have received less attention. We propose a new framework for information integration that highlights visual integration and cognitive integration. During visual integration, pattern recognition processes are used to form visual clusters of information; these visual clusters are then used to reason about the graph during cognitive integration. In 3 experiments, the processes required to extract specific information and to integrate information were examined by collecting verbal protocol and eye movement data. Results supported the task analytic theories for specific information extraction and the processes of visual and cognitive integration for integrative questions. Further, the integrative processes scaled up as graph complexity increased, highlighting the importance of these processes for integration in more complex graphs. Finally, based on this framework, design principles to improve both visual and cognitive integration are described.

Experimental evaluation of software documentation formats

Abstract Four controlled experiments investigated the effectiveness of different documentation formats for presenting information about computer programs. Nine different documentation formats (some quite novel) were created by varying three different forms of symbology (natural language, constrained language, and ideograms) and three different spatial arrangements (sequential, branching, and hierarchical). Professional programmers used these formats as aids to comprehend (Experiment 1), code (Experiment 2), debug (Experiment 3), and modify (Experiment 4) modular-sized programs. For each programming task, a model of the cognitive activities a programmer would perform generated hypotheses about the effectiveness of different formats. Natural language was found to be less effective in assisting most of the tasks studied than a constrained language or ideograms. A smaller effect was observed (less frequently than expected) for the spatial arrangment in situations where control flow information aided the task. The largest effect in the experiments, individual differences among the participants, accounted for between a third and one-half of the variation in performance.

Reducing the disruptive effects of interruption: A cognitive framework for analysing the costs and benefits of intervention strategies

Interruptions are ubiquitous, and they can lead to disastrous consequences. The goal of this paper is to describe remedies that have been proposed to reduce the disruption caused by interruptions based on an understanding of how principles of human cognitive processing bear on the sequence of events that take place during an interruption. We show that interruptions tap disparate cognitive operations, from attention to decision making to memory. We illustrate how these cognitive processes can lead to interruption-induced errors, and how they can help in understanding potential problems with remedies that have been proposed to ameliorate those effects. We present a framework in which the load imposed by the task and the cost of an error suggests the types of solutions that should be considered for a given domain. We then discuss the implications of this approach for understanding and reducing the negative effect of interruptions in transportation domains.

Program design methodologies and the software development process

Abstract This research examined program design methodologies which claim to improve the design process by providing strategies to programmers for structuring solutions to computer problems. In this experiment, professional programmers were provided with the specifications for each of three non-trivial problems and asked to produce pseudo-code for each specification according to the principles of a particular design methodology. The measures collected were the time to design and code, percent complete, and complexity, as measured by several metrics. These data were used to develop profiles of the solutions produced by different methodologies and to develop comparisons among the various methodologies. These differences are discussed in light of their impact on the comprehensibility, reliability, and maintainability of the programs produced.

Do Interruptions Affect Quality of Work

Objective: The aim of this study was to determine if interruptions affect the quality of work. Background: Interruptions are commonplace at home and in the office. Previous research in this area has traditionally involved time and errors as the primary measures of disruption. Little is known about the effect interruptions have on quality of work. Method: Fifty-four students outlined and wrote three essays using a within-subjects design. During Condition 1, interruptions occurred while participants were outlining. During Condition 2, interruptions occurred while they were writing. No interruptions occurred in Condition 3. Results: Quality of work was significantly reduced in both interruption conditions when compared to the non-interruption condition. The number of words produced was significantly reduced when participants were interrupted while writing the essay but not when outlining the essay. Conclusion: This research represents a crucial first step in understanding the effect interruptions have on quality of work. Our research suggests that interruptions negatively impact quality of work during a complex, creative writing task. Since interruptions are such a prevalent part of daily life, more research needs to be conducted to determine what other tasks are negatively impacted. Moreover, the underlying mechanism(s) causing these decrements needs to be identified. Finally, strategies and systems need to be designed and put in place to help counteract the decline in quality of work caused by interruptions.

Mitigating disruptive effects of interruptions through training: what needs to be practiced?

It is generally accepted that, with practice, people improve on most tasks. However, when tasks have multiple parts, it is not always clear what aspects of the tasks practice or training should focus on. This research explores the features that allow training to improve the ability to resume a task after an interruption, specifically focusing on task-specific versus general interruption/resumption-process mechanisms that could account for improved performance. Three experiments using multiple combinations of primary tasks and interruptions were conducted with undergraduate psychology students. The first experiment showed that for one primary and interruption task-pair, people were able to resume the primary task faster when they had previous practice with the interruption. The second experiment replicated this finding for two other sets of primary and interruption task-pairs. Finally, the third experiment showed that people were able to resume a primary task faster only when they had previous practice with that specific primary and interruption task-pair. Experience with other primary and interruption task-pairs, or practice on the primary task alone, did not facilitate resumption. This suggests that a critical component in resuming after an interruption is the relationship between two tasks. These findings are in line with a task-specific mechanism of resumption and incompatible with a general-process mechanism. These findings have practical implications for developing training programs and mitigation strategies to lessen the disruptive effects of interruptions which plague both our personal and professional environments.

Interruptions Disrupt Reading Comprehension

Previous research suggests that being interrupted while reading a text does not disrupt the later recognition or recall of information from that text. This research is used as support for Ericsson and Kintschs (1995) long-term working memory (LT-WM) theory, which posits that disruptions while reading (e.g., interruptions) do not impair subsequent text comprehension. However, to fully comprehend a text, individuals may need to do more than recognize or recall information that has been presented in the text at a later time. Reading comprehension often requires individuals to connect and synthesize information across a text (e.g., successfully identifying complex topics such as themes and tones) and not just make a familiarity-based decision (i.e., recognition). The goal for this study was to determine whether interruptions while reading disrupt reading comprehension when the questions assessing comprehension require participants to connect and synthesize information across the passage. In Experiment 1, interruptions disrupted reading comprehension. In Experiment 2, interruptions disrupted reading comprehension but not recognition of information from the text. In Experiment 3, the addition of a 15-s time-out prior to the interruption successfully removed these negative effects. These data suggest that the time it takes to process the information needed to successfully comprehend text when reading is greater than that required for recognition. Any interference (e.g., an interruption) that occurs during the comprehension process may disrupt reading comprehension. This evidence supports the need for transient activation of information in working memory for successful text comprehension and does not support LT-WM theory.

The red-line of workload: Theory, research, and design

Multi-tasking is now ubiquitous component of our lives; despite the fact that we all can cite an incident where multi-tasking put us in a difficult situation. The reason so many of us do multi-task is that most of the time we are capable of effective dual task performance. Hart and Wickens (2008) have defined the point where one traverses safe and effective multi-tasking to dangerous and ineffective multi-tasking as the “red-line” of workload. In this panel, we will discuss this “red-line” of workload from the theoretical, empirical, and practical viewpoints. To that end, we first examine what theories of attention can help guide empiric search for this red line and where these theories must be expanded with further research. The greatest need is research that will allow human factors practitioners to identify the red line of workload before a system has been developed. One approach to achieving this research is to leverage the approach of industrial ergonomics, which has successfully defined physical workload limits by using data from safety incidents. Another avenue of research to be discussed is that which will lead to refinement of our theories and understanding of cognitive function to improve our ability to predict the red line. Next we move to the problem of evaluating systems to ensure that the red line of workload is not crossed. In particular, we will discuss the possibility of using task analysis, specifically, CPM-GOMS to predict if a system design will lead to excessive workload. Finally, we present two system design strategies for maintaining a cognitive workload that is below the red-line. The first of these is an adaptive automation using eye-tracking to reduce screen clutter when it appears workload has become so high an error may occur. The second design strategy presents four research based design principles for reducing workload to acceptable levels.