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Objective: We examined how providing artificially high or low statements about automation reliability affected expectations, perceptions, and use of automation over time. Background: One common method of introducing automation is providing explicit statements about the automation's capabilities. Research is needed to understand how expectations from such introductions affect perceptions and use of automation. Method: Explicit-statement introductions were manipulated to set higher-than (90%), same-as (75%), or lower-than (60%) levels of expectations in a dual-task scenario with 75% reliable automation. Two experiments were conducted to assess expectations, perceptions, compliance, reliance, and task performance over (a) 2 days and (b) 4 days. Results: The baseline assessments showed initial expectations of automation reliability matched introduced levels of expectation. For the duration of each experiment, the lower-than groups' perceptions were lower than the actual automation reliability. However, the higher-than groups' perceptions were no different from actual automation reliability after Day 1 in either study. There were few differences between groups for automation use, which generally stayed the same or increased with experience using the system. Conclusion: Introductory statements describing artificially low automation reliability have a long-lasting impact on perceptions about automation performance. Statements including incorrect automation reliability do not appear to affect use of automation. Application: Introductions should be designed according to desired outcomes for expectations, perceptions, and use of the automation. Low expectations have long-lasting effects.

Objective: An empirical investigation was done to determine if there are age-related differences attributable to costs in reliance on a decision aid. Background: Costs of reliance on a decision aid may affect reliance on the aid. Older and younger adults may not perceive and respond to a dynamic cost structure equally or objectively. Method: Sixteen older adults (65—74 years) and 16 younger adults (18—28 years) performed a counting task with an imperfect decision aid. Two types of costs were manipulated: (a) cost of error (CoE) and (b) cost of verification (CoV). The percentage of trials in which participants agreed with the decision aid and did not perform the task manually was recorded as reliance. Results: Participants decreased their reliance as the CoE increased and increased their reliance with a lower CoV; however, they tended to under-rely on the decision aid. Younger adults tended to change their reliance behavior more than older adults did with the changing cost structure. Conclusions: Older and younger adults appear to interpret costs differently, with older adults being less responsive to changes in costs. Older adults may have been less able to monitor the changing costs and hence not adapt to them as well as younger adults. Application: Designers of decision aids should consider explicitly stating costs associated with reliance on the aid, as individuals may differ in how they interpret and respond to changing costs.

Objective: The present study examined the relationship between two distinct subfactors of spatial ability and performance in an information search task modeled on browsing the Web. Background: Previous studies have found relationships between various measures of spatial ability and performance in a wide variety of computerbased tasks. Method: In the search task 101 participants (18-29 years of age) searched for the answer to a question by navigating the system. They completed the experimental task as well as a battery of cognitive ability measures that included two different measures of spatial ability. Results: The results indicate that spatial orientation ability was related to performance with tasks that were high in their navigational requirement (engendered by the use of a novel aid), whereas spatial visualization was unrelated to performance in any task condition. Conclusion: A closer inspection of the cognitive requirements of a task may reveal what interventions could be most useful when designing computer systems or developing training programs. Application: Given the unique differences between the different spatial abilities, the current results suggest the design of navigational aids that place less demand on spatial orientation ability. Date received: March 4, 2004 Date accepted: December 27, 2004

We developed an integrative perspective on the empirical evidence supporting the influence of particular variables on the warning process based on a broad review of the warning literature. The warning process is described in terms of the following four components: notice, encode, comprehend, and comply. Relevant variables are classified as person variables (characteristics of the individual interacting with the warning) and warning variables (characteristics of the warning itself or the context in which the warning appears). This integrative perspective yields general principles about the variables that influence the warning process and serves as a resource for warning developers and as a guide to facilitate effective analysis of warnings. We also identify aspects of the warning process that are not well understood, directions for effective methods of intervention, and a research agenda for future efforts. Actual or potential applications of this research include improving the design of warnings.

ObjectiveWe examined the potential of conversational agents (CAs) to support older adults' self-care related to chronic illness in light of lessons learned from decades of pedagogical agent research, which investigates the impact and efficacy of CAs for a wide range of learners.BackgroundThe role of CAs in education (i.e., pedagogical agents) has been long studied, but their potential for supporting self-care has received less attention, especially for older adults.MethodsWe reviewed work on pedagogical agents and considered how it informs the design of CAs for older adults. We propose a framework for designing CAs to support older adult self-care, which organizes a review of work in this area and integration with the pedagogical agent literature.ResultsOur review of the pedagogical agent literature revealed an evolution from teaching machines to interactive, social systems that influence student motivational as well as learning outcomes. To integrate this review with work on CAs and self-care, we developed a framework that specifies how self-care goals evolve with stages of an illness, communication goals that support self-care at each stage, patient needs, and requirements for CAs to support these needs. The review identified an agenda for future research on CA functions and features that help older adults accept need for self-care, establish self-care, and sustain self-care over time.ConclusionsIntegrating insights from the pedagogical agent literature with research on developing CAs for self-care defines an agenda for developing and evaluating CAs to help older adults manage illness.

Objective: This study examined how individuals, younger and older, interacted with an imperfect automated system. The impact of workload on performance and automation use was also investigated. Background: Automation is used in situations characterized by varying levels of workload. As automated systems spread to domains such as transportation and the home, a diverse population of users will interact with automation. Research is needed to understand how different segments of the population use automation. Method: Workload was systematically manipulated to create three levels (low, moderate, high) in a dual-task scenario in which participants interacted with a 70% reliable automated aid. Two experiments were conducted to assess automation use for younger and older adults. Results: Both younger and older adults relied on the automation more than they complied with it. Among younger adults, high workload led to poorer performance and higher compliance, even when that compliance was detrimental. Older adults' performance was negatively affected by workload, but their compliance and reliance were unaffected. Conclusion: Younger and older adults were both able to use and double-check an imperfect automated system. Workload affected how younger adults complied with automation, particularly with regard to detecting automation false alarms. Older adults tended to comply and rely at fairly high rates overall, and this did not change with increased workload. Application: Training programs for imperfect automated systems should vary workload and provide feedback about error types, and strategies for identifying errors. The ability to identify automation errors varies across individuals, thereby necessitating training.

Objective: The purpose of this study was to investigate the relationship between strategy use and search success on the World Wide Web (i.e., the Web) for experienced Web users. An additional goal was to extend understanding of how the age of the searcher may influence strategy use. Background: Current investigations of information search and retrieval on the Web have provided an incomplete picture of Web strategy use because participants have not been given the opportunity to demonstrate their knowledge of Web strategies while also searching for information on the Web. Methods: Using both behavioral and knowledge-engineering methods, we investigated searching behavior and system knowledge for 16 younger adults (M = 20.88 years of age) and 16 older adults (M = 67.88 years). Results: Older adults were less successful than younger adults in finding correct answers to the search tasks. Knowledge engineering revealed that the age-related effect resulted from ineffective search strategies and amount of Web experience rather than age per se. Our analysis led to the development of a decision-action diagram representing search behavior for both age groups. Conclusion: Older adults had more difficulty than younger adults when searching for information on the Web. However, this difficulty was related to the selection of inefficient search strategies, which may have been attributable to a lack of knowledge about available Web search strategies. Application: Actual or potential applications of this research include training Web users to search more effectively and suggestions to improve the design of search engines.

Two experiments were conducted to determine if age affects comprehension for explicit and implied warning information and, if so, to reveal the nature of such effects. Experiment 1 measured younger (18-23 years) and older (65-75 years) adults' comprehension for real-world warnings via a verification test presented immediately after reading the warnings or after a delay. In Experiment 2, younger (18-22 years) and older (64-76 years) participants also read fabricated warnings that were inconsistent with real-world knowledge. In both experiments, older adults frequently failed to infer the correct hazard and safety information. The older adults also had trouble understanding warning information even when it was explicitly stated (when no inferences were required), especially when memory demands were high and product-specific knowledge could not be used. That many of the older adults did not understand commonly used product warnings indicates that the wording on many household products is not conducive to being understood by everyone who uses them. Actual or potential applications of this research include the recommendation that designers of product labels, warnings, and instructions should consider minimizing memory load and maximizing opportunities for knowledge application when designing consumer warnings.

We examined the differential benefits of instructional materials for younger and older adults learning to use a home medical device. Participants received training on use of a blood glucose meter via either a user manual (a text guide with pictures) or an instructional video. Performance was measured immediately and then after a 2-week retention interval. Type of instruction was critical for determining older adults' performance. Older adults trained using the manual had poorer performance than did all other groups. After only 1 calibration, older adults who received video training performed as accurately as did the younger adults. Older adults' performance was more influenced by the retention interval; however, the benefit of the video training was maintained for the older adults across the retention interval. Confidence ratings paralleled subjective workload ratings. The data provide practical information to guide the development of training programs for systems that will be used by both younger and older adults; they also demonstrate the need for age-related usability testing even for training program design.

Beliefs about warnings and habits associated with reading them were assessed for 863 individuals of various ages. Information gathered for various common household products included (a) how frequently people attend to warning information, (b) the degree of risk they believe is involved during product usage, and (c) how important they believe warnings are for different product types. Also assessed were perceived helpfulness and comprehension for symbols commonly found on product labels or on signs in the environment. Respondents 55 years and older reported reading product warnings more frequently than did younger adults, although they generally perceived warnings as less important. However, no overall age-related differences were found for perceived level of risk involved in using different product types. Although older adults generally perceived symbols to be very helpful when using a particular product, their comprehension levels were poorer than those of younger adults for half of the symbols. Overall, these data suggest that adults of all ages do read warnings on a variety of product types and that they believe warning information is important. This research illustrates the importance of including older adults in usability studies during the development of warning systems, given age-related effects may be associated with some aspects of the warning processing but not others.

Context has an important influence on performance in a variety of tasks. In the present experiment, the context of interest was the number of consecutive trials under identical search conditions. We were interested in how individuals learn to benefit from one form of contextual cues, the time course of such benefit, and the effects of contextual manipulations on general learning, feature learning, and automatic process development. We investigated these issues using a visual search task in which we could manipulate both consistency and learning context. The results suggest that the manipulation of context influenced feature learning; that is, at least 10 consecutive trials were required before optimal scanning strategies could be developed and/or instituted. However, the training context manipulation did not affect the acquisition of an automatic attention response in a consistent task or the acquisition of a general skill for a varied task. Implications for task and system design and the development of training programs are discussed.