Multiple Resource Theory Research Articles

Multiple Resource Theory II

Multiple resource theory proposes that attention is a process of resource allocation. These resources may be shifted among different modalities and information-processing tasks. This study investigated whether selective attention to a particular television modality results in different levels of attention to the visual and auditory modalities. Two independent variables manipulated selective attention—the modality with the most information (audio or video) and viewers' instructed focus (audio or video). These variables were fully crossed in a within-subjects experimental design. Attention levels were investigated by measuring reaction times to cues in each modality (audio tones and color flashes). All five manipulation checks suggest that subjects were able to focus on a particular message channel. Reactions to cues were faster, however, when the audio channel contained the most information and when viewers focused on the audio channel. These results suggest a common pool of limited attentional resources and therefore bimodal attention.

Multiple Resource Theory I

Comprehending television is a complex process. Multiple resource theory proposes that the necessary resources are limited. Limitations, however, depend on four separate factors. First, resources are used by three different tasks—attention, meaning-level processing, and memory. Demands arise from individual tasks and combinations. The consequences of reaching limitations are different for each task. Second, television's auditory and visual modalities use different symbol systems. Audio information might be more difficult to process and requires more resources. Third, television stimuli might contain the meaningful information in either the auditory or visual modality. Meaningful information might require more processing and resources and should result in resource shifts. Fourth, television programs use varying levels of redundancy. Whereas processing two modalities generally requires additional resources, actual demands depend on the level and nature of the redundancy. As a result of these four factors, resource limitations can inhibit one process, modality, or attribute. Systematic study of these outcomes is necessary.

Is Performance Tradeoff an Experimental Artifact?

The purpose of the present study was to examine the utility of the resource notion, which is the basis for the secondary task technique of workload assessment. The unbiased optimum-maximum method proposed by Navon (1984) was used to manipulate task priority without conveying to the subjects that time-shared performance must tradeoff. Three task pairs that fell on a continuum of degree of shared resources were tested. The data showed that performance tradeoff is not an experimental artifact. Moreover, the data suggested that increased degree of shared resources led to increased resource allocation optimality and decreased time-sharing efficiency, as predicted by multiple resource theories. The present data suggests that resource theories are useful in explaining dual task performance, and that the secondary task can be a useful workload assessment tool.

Modality Congruence, Multiple Resource Theory and Intermedia Broadcast Comparisons: An Elaboration

Abstract Relevant research literature and theoretical bases on the effects of message congruence among multiple stimulus modalities are reviewed to demonstrate the importance of modality congruence to the subject of comparisons between TV and radio broadcast media, in part in response to a comment article by Smith and Buchholz (1991). Refinements and extensions to Multiple Resource Theory are offered and suggestions for research provided.

Multiple Resource Theory and Consumer Processing of Broadcast Advertisements: An Involvement Perspective

Abstract In an attempt to reconcile past modality research, Leigh (1991) used Multiple Resource Theory while emphasizing the role of audio / visual congruency and task difficulty. This paper provides an alternative interpretation by reviewing Multiple Resource Theory from an involvement perspective. Past modality studies are organized and integrated based on the level of consumer involvement in the stimulus ad. Empirical findings are shown to be highly consistent with this approach. Suggestions for future modality research are presented.

Attention Theory as a Guide to Part-Training for Instruction of Naval Air-Intercept Control

Air-intercept control is a complex Navy combat task which requires a radar operator to advise a pilot of optimum headings for avoiding, meeting, or intercepting other aircraft. The goal of the research reported here was to explore procedures for teaching some critical elements of air-intercept control with a pc-based version of the training simulation that is normally used for instruction. Principles derived from attention theory, and in particular Multiple Resource Theory (Wickens, 1984), were used to guide the development of two part-training strategies. In one strategy, specific skill-based elements of the task were taught in isolation and were then recombined into the whole task. In another strategy, an abstract procedural task was added by isolating those features that contributed to the spatial and temporal coherence of the whole task. A transfer of training design was used to test these two part-training conditions. The procedural-based version of the task emerged as a training strategy that could help students develop resistance to potentially disruptive effects of making the task more difficult. The results are viewed as supporting an approach to training that attempts to alleviate resource overload so that learning may proceed with maximum efficiency while, at the same time, allowing critical task elements related to time-sharing skills to be practiced.

Selective Attention with Auxiliary Automobile Displays

Emerging intelligent vehicle-highway systems technology will have a profound impact on the design of future driver interfaces. A series of experiments was conducted to investigate basic human factors issues relating to the design and use of auxiliary in-vehicle displays. A total of thirty healthy male and female student volunteers drove in a moving-base driving simulator and performed auxiliary cognitive tasks on a CRT display. Measures of driving performance, attentional behaviour, auxiliary task performance and workload indicated that performing auxiliary tasks while driving can significantly degrade performance. The effects were manifested even more strongly in subjects' attentional responses. Multiple Resource Theory predictions were not upheld, indicating that the nature and extent of intrusion were relatively robust with respect to task resource structure. Finally, the results provided no evidence that the payment of bonuses was effective in shifting relative resource allocation between these tasks.

Effects of redundancy in the comparison of speech and pictorial displays in the cockpit environment

Synthesised speech and pictorial displays were compared in a spatially compatible simulated cockpit environment. Messages of high or low levels of redundancy were presented to subjects in both modality conditions. Subjects responded to warnings presented in a warning-only condition and in a dual-task condition, in which a simulated flight task was performed with visual and manual input/output modalities. Because the amount of information presented in most real-world applications and experimental paradigms is quantifiably large with respect to present guidelines for the use of synthesised speech warnings, the low-redundancy condition was hypothesised to allow for better performance. Results showed that subjects respond quicker to messages of low redundancy in both modalities. It is suggested that speech messages with low-redundancy levels were effective in minimising message length and ensuring that messages did not overload the short-term memory required to process and maintain speech in memory. Manipulation of phrase structure was used to optimise message redundancy and enhance the conceptual compatibility of the message without increasing message length or imposing a perceptual cost or memory overload. The results also suggest that system response times were quicker when synthesised speech warnings were used. This result is consistent with predictions from multiple resource theory which states that the resources required for the perception of verbal warnings are different from those for the flight task. It is also suggested that the perception of a pictorial display requires the same resources used for the perception of the primary flight task. An alternative explanation is that pictorial displays impose a visual scanning cost which is responsible for decreased performance. Based on the findings reported here, it is suggested that speech displays be incorporated in a spatially compatible cockpit environment because they allow equal or better performance when compared with pictorial displays. More importantly, the amount of time that the operator must direct his vision away from information vital to the flight task is decreased.

Multiple resources for processing and storage in short-term working memory.

A frequent assumption in cognitive psychology is that performance in decision making and planning is severely restricted by the limited capacity of short-term working memory. Many predictions of this theory have not been supported, possibly because working memory may be composed of multiple resources rather than a single resource. The present experiments study two tasks, both involving memory for digits. Although these tasks can employ the same modality for input and for responding, they appear to differ in their demands for working memory resources. Specifically, the tasks appear to differ in resources required for processing at input, and they also differ in resources in the sense of storage capacity. The results support a version of multiple-resource theory applied to working memory in which resource composition depends on internal mediators even when stimulus and response modality are held constant.

Capacity Limitations in Human Information Processing: Theory and Applications

Two factors that are critical aspects of complex system performance are system design and operator training. The contribution of each of these factors becomes paramount as increases in system complexity demand more sophisticated operator timesharing skills to monitor and control system operations safely and efficiently. In order to increase human operator skill levels, improvements in system design must be achieved to make aspects of monitoring and controlling tasks more commensurate with human abilities. Secondly, more effective and efficient training programs must be developed to allow human operators to acquire and maintain appropriate skill levels. Before these improvements can be accomplished, however, a greater understanding of the capabilities and limitations of the human information processing system must be obtained. In a typical modern system (e.g., aircraft cockpit, centralized control room of a power plant or battle management system) the human may perform many tasks concurrently, including visual search, memory search, retention and recall, comprehension, reasoning, judgement and decision making, and executing fine motor movements. Although some combinations of these kinds of tasks may be compatible and non-interfering, other task combinations may interfere and compete for the human's limited information processing capacity, creating overload conditions. The consequence of the human operator's low threshold for overload leads to increased probability of error, with subsequent deteriorations in system performance. There are two theoretical approaches to human attention and information processing that have implications for system design and operator training issues in the context of timesharing and high workload situations. Multiple resource theory and automatic/controlled processing theory have each stimulated much empirical work that provided useful data on human timesharing abilities. Such data have provided the basis for predicting task combinations and training requirements that allow high levels of performance under timesharing and high workload situations. The purpose of this symposium is to describe recent empirical developments that may further our understanding of human information processing capabilities and limitations, particularly under timesharing and high workload conditions. The set of papers includes theoretical and applied treatments of multiple resource and automaticity theories. The issues discussed include the advantages and disadvantages of spreading information input over different sensory modalities (e.g., visual and auditory), development of training methods to acquire sophisticated high level cognitive skills quickly and efficiently, measurement of information processing capacity required by specific task combinations, and a delineation of the characteristics and limitations of working memory.

A Human Information Processing Theory of Skill Acquisition: A Training Systems View

This paper outlines a human information processing theory applicable to acquisition of military skills with a high processing load. The proposed approach integrates two complementary streams of thinking: (1) multiple resource theory; and (2) the concept of automaticity.

Time-Sharing Visual and Auditory Tracking Tasks

Multiple resource theory suggests that distributing demands over separate resources will reduce resource competition and improve time-sharing efficiency. A recent hypothesis however suggests that the benefits of utilizing separate resources for the time-shared tasks may be mitigated if the two tasks are integrated. The present experiment examined the benefits of distributing the input demands of two tracking tasks as a function of task integrality. Visual and auditory compensatory tracking tasks were used. Timesharing two tracking tasks with the same order of control is said to be more integrated than with different orders of control. Results show that presenting the two tracking signals in two input modalities did not improve time-sharing efficiency. This was attributed to the difficulty insensitivity phenomenon. Whether utilizing the same control dynamics between the time-shared tasks could generate an integrality effect was unclear from the present data. A continuous auditory task that could offer comparable spatial information as the visual counterpart was proposed to be valuable for studying attentional processes, information display alternatives, and workload assessment.

Display Formatting in Information Integration and Nonintegration Tasks

The impact of various formats used in the design of visual displays was investigated in two reaction-time (RT) experiments. Analog, digital, and verbal formats were employed with numerical judgment tasks requiring either the integration or non integration of display elements. As predicted by multiple resource theory, the dual task (nonintegration) benefited from a mixed-format display. Integration tasks, however, revealed a contrasting benefit of pure-format displays. Generally speaking, analog indicators were responded to more quickly than were digital or verbal indicators. Three guidelines for display design are suggested.

Effects of information-processing demands on physiological response patterns.

The present study investigated the effects of increased attentional and encoding/rehearsal demands on a number of physiological measures. Encoding/rehearsal demands were varied by manipulating the number of letters (1, 3, or 5) comprising a briefly presented set that the subject was instructed to encode, retain, and, 5 s later, compare with a single test letter. Attentional demands were varied by presenting the subject with a cue stimulus (the numeral 1, 3, or 5) 5s prior to the presentation of the letter set, informing the subject of the number of letters contained therein. The physiological measures recorded were heart rate, eyeblinks, “probe-evoked” potentials sampled from the intervals preceding and following the letter set, and “task-evoked” potentials elicited by the cue, memory set, and test stimuli. Unique patterns of physiological activity occurred in the intervals preceding and following the memory set. In the interval preceding the memory set, where attentional demands were varied by set size, probe ERP P1-N1 amplitude increased with set size. In the subsequent interval, where encoding and rehearsal demands were varied, probe ERP N1-P2 amplitude declined with increasing set size. There was also evidence for interval and set-size effects on heart rate, blink rate, and task ERPs. These results have implications for multiple-resource theories of attention.

Comparison of Speech and Pictorial Displays in a Cockpit Environment

A current trend in cockpit design is to incorporate synthesized speech to present secondary information. Multiple-resource theories of information processing support this, but theories of stimulus/central-processing/response compatibility suggest that spatial information presented visually may have some advantages over speech if the response is manual. Two experiments compare response performance over single and dual tasks when information was presented pictorially and by speech. Pictorial subjects responded more quickly than did speech subjects. The addition of the visual tracking task in the dual-task condition had a differential effect on performance, depending on the modality of the primary task and the rate at which information was presented. The dual task impeded performance more in the fast and medium presentation rates for the speech condition but had little differential effect across rates for the pictorial condition. Analysis of the error data indicated that subjects in the pictorial condition were better able to maintain the context of the emergency than those in the speech condition. Results are discussed in terms of current theories of information processing.

Timesharing, Cognition, and Human Performance in Complex Information Systems

Applications of advanced technology to modern systems have resulted in the requirement for the human operator to process large volumes of information at rapid rates. Such systems may impose substantial attentional and timesharing requirements on the operator, often exceeding human information processing capabilities. Consequently, there is a critical need to investigate and understand the human information processing system in order to identify generalizable, empirically derived principles of human timesharing capabilities. Of particular interest are current theoretical approaches to human attention and information processing limitations that suggest ways to improve timesharing performance. Two of these approaches, automatic information processing theory and multiple resource theory are especially relevant to the timesharing problem.

Multiple resources: The concepts of task difficulty and response requirements

The variables of task difficulty and response requirements were examined within the multiple resources framework. The performance of 54 undergraduates was monitored on a visual target detection task as the difficulty of auditory shadowing was manipulated. Response competition was examined by varying the time at which subjects responded to the visual target. In line with multiple resources theory, there were no significant differences in target detection as a function of different demands of auditory shadowing, and there was no evidence for switching between auditory and visual inputs. Subjects were devoting their effort toward shadowing as measured by control trials of shadowing alone. Although evidence for response competition was not obtained in the hypothesized direction, the subjects who responded to visual targets while continuing to shadow performed better than other subjects. Alternative theories and the notion that effort may refer to the range of available processing strategies are discussed.

Changes in Performance in Workload with Training

The effects of practice on accuracy, speed, and resource load are briefly discussed. Procedures for measuring resource load and training of high performance skills are illustrated. Analysis of task consistency and procedures for establishing the marginal utility of various training options are described. The alternatives of time-line analysis, subjective measures and multiple resource theory are commented on.

There's a Voice in the Sky; but Can a Picture Tell you More?

A current trend in cockpit design is to incorporate synthesized speech to present secondary information. Multiple resource theories of information processing support this, but theories of stimulus-central processing-response compatibility suggest that spatial information presented visually may have some advantages over speech. An experiment was run comparing tracking and response performance when information was presented pictorially and by speech. Pictorial subjects responded quicker and improved more with learning than did speech subjects. More research on the spatial advantages of pictorial displays is needed before too many speech displays are incorporated into the cockpit.