Age differences and the acquisition of spatial knowledge in a three-dimensional environment: Evaluating the use of an overview map as a navigation aid

This study examined age differences in the use of an electronic three-dimensional (3D) environment, and how the age differences were affected by the use of an overview map as a navigation aid. Task performance and the subjects’ acquisition of configural knowledge of the 3D-environment were assessed. Impact of spatial ability and prior experience on these measurements were also investigated. One group of older subjects (n=24) and one group of younger subjects (n=24) participated. An overall hypothesis for the work presented here was that differences in learning to and performing navigational tasks in the physical world are similar in learning and performing navigational tasks in the virtual world. The results showed that the older participants needed more time to solve the tasks; and similar to navigation in the physical world, the older participants were less likely to create configural knowledge. It could not be established that older participants benefited more from an overview map as cognitive support than younger subjects, except in the subjective sense: the older users felt more secure when the map was there. The map seemed to have supported the older users in creating a feeling of where objects were located within the environment, but it did not make them more efficient. The results have implications for design; in particular, it brings up the difficult issue of balancing design goals such as efficiency in terms of time and functionality, against maintaining a sense of direction and location in navigational situations.     

Effects of age, speech rate, and environmental support in using telephone voice menu systems

Age differences in the use of telephone menu systems were investigated in two experiments. Participants from three age groups (younger: 18-39; middle-aged: 40-59; older: 60+ years) were required to obtain specified information or perform some action using simulated voice menu systems. Measures reflecting task performance, menu navigation, and subjective responses were collected. The focus in Experiment 1 was on examining the effect of speech rate. Data from 196 participants indicated age differences in performance, especially for complex problems. There was no effect of speech rate on any of the performance measures. Experiment 2 examined two types of support devices: a screen phone and a graphical aid. Data from 114 participants indicated that the screen phone provided some benefits in navigational efficiency. In terms of performance, the older participants benefited more from the graphical aid and the younger participants performed better with the screen phone. Actual or potential applications of this research include guidance in the use of support devices that can reduce memory demands and the identification of appropriate speech rates.     

The effects of zoomable user interfaces and user age in searching for a target with a mouse on a two-dimensional information space

A zoomable user interface (ZUI) is a useful function to help users deal with large information spaces displayed within a screen. Although used in many applications, ZUIs have not been sufficiently studied in terms of usability. Usability problems may be more crucial for older people than younger ones. The objective of this study is to examine the effects of a combination of two zoom factors (three zoom focus methods: original-center, re-center, and aiming-point; and two zoom scales: +100% and +400%) for two age groups (younger and older adults) on mouse-based information searching tasks in a map-type two-dimensional information space. Twenty four volunteers (twelve users per age group) participated in the experiments by answering a pair of questions about fifty movie information topics. Task completion time, number of operations, and number of errors were selected as performance measures, and a subjective assessment of satisfaction was collected. Older adults used the tested ZUIs less efficiently and precisely than younger adults. The effects of zoom focus methods vary with zoom scale levels regardless of the age groups. The participants also preferred using the aiming-point focus regardless of zoom scale and using the re-center focus with the +400% scale. We discuss potential implications of the age-related performance differences and the effects of ZUI functions, and suggest some ZUI design guidelines in conclusion. We expect that the findings can be used as basic resources in designing various web services and applications for older computer users.

Relevance to industry

Given that a zoomable user interface is widely used in basic geographic information systems, web services, and various applications, using a selective-focus method such as the aiming-point focus can improve computer users’ usability; in particular, the zooming functions will greatly help older people to explore large information spaces quickly and easily.     

Manual dexterity of older Mexican American adults: a cross-sectional pilot experimental investigation

This paper reports results from an experimental pilot study performed to quantify the manual dexterity of older Mexican American adults. The Purdue pegboard test, a two-arm coordination test, and a hand-tool dexterity test were used in this study. To enable cross-sectional comparisons of manual dexterity measures of older Mexican American adults with young Mexican American adults, these tests were administered to 18 older Mexican American adults aged 63–85 (mean age: 71.3 years, SD: 7.0 years), recruited from senior recreation centers in El Paso, and eighteen young adults aged 21–32 (mean age: 25.6 years, SD: 3.8 years) recruited from the student body at the University of Texas at El Paso. For the Purdue pegboard test, the number of pegs placed in 30 s using the preferred hand, the non-preferred hand, and both hands were first individually monitored. Then, scores on an assembly task using the Purdue pegboard were obtained. For the two-arm coordination test, participants were required to trace a star pattern with a stylus using both hands. The time for task completion and the number of errors made during task performance were monitored. For the hand-tool dexterity test, participants were required to use common hand tools and remove nuts and bolts from one side of a wooden upright, and to assemble nuts and bolts in the corresponding holes on the other side of the upright. The time taken for task completion was recorded. Since modified Levene's test showed equality of variances, two sample t-tests, comparing the mean responses of older adults with the mean responses of young adults for each individual test, were conducted. Results indicate that responses for the older adults were statistically significant different (p<0.001) from young adults for all Purdue pegboard tasks. On the average, older adults performed significantly slower (p<0.001) than young adults on the two-arm coordination test, and committed more errors before task completion (p<0.05). Older adults also took longer to complete the hand-tool dexterity task compared to their younger counterparts (p<0.05). In addition to the t-tests, manual dexterity performance measures from older adults were regressed with age to determine the cross-sectional age effects on manual dexterity measures. Results indicate that all Purdue pegboard performance measures were significantly affected by age (p<0.05). The time to complete the two-arm coordination test was significantly linearly related to age (p<0.05). However, the number of errors committed by older adults in the performance of the two-arm coordination test was not significantly linearly related to age. Time to complete the hand-tool dexterity was also significantly linearly related to age (p<0.05). Accommodating age-related changes in manual dexterity is important for job design in industry, especially in industries employing older adults requiring significant assembly and hand-tool use.

Relevance to industry

Given the aging of the industrial workforce, it is important to understand how manual dexterity is affected by age, so that jobs requiring significant manual dexterity for task initiation, task performance and task completion are designed to fit older adult dexterity levels.     

Maintaining and modifying pace through tactile and multimodal feedback

Older adults are recommended to remain physically active to reduce the risk of chronic diseases and to maintain psychological well-being. At the same time, research also suggests that levels of fitness can be raised among this group. This paper describes the development and evaluation of a mobile technology, which enables older adults to monitor and modify their walking habits, with the long-term aim of sustaining appropriate levels of physical activity. An empirical study was conducted with twenty older adults to determine the feasibility of the proposed solution, with results indicating that tactile signals could be perceived while in motion and could support participants in walking at a range of paces. However, the effects were difficult to discern due to limitations of the hardware. In response, a novel low-cost prototype was developed to amplify vibrations, and effectiveness of redundant auditory information was investigated with the goal of enhancing the perception of the cues. A second study was conducted to determine the impact of multimodal feedback on walking behavior. Findings revealed that participants were able to maintain a desired level of pace more consistently when redundant auditory information was presented alongside the tactile feedback. When the visual channel is not available, these results suggest that tactile cues presented via a mobile device should be augmented with auditory feedback. Our research also suggests that mobile devices could be made more effective for alternative applications if they are designed to allow for stronger tactile feedback.     

Light pen use and practice minimize age and hand performance differences in pointing tasks

We contrasted performance with mouse and light pen input devices for younger, middle-aged, and older adults (N = 72) who were experienced mouse users. Participants used both preferred and nonpreferred hands to perform a menu target selection task. The light pen minimized age differences in performance relative to the mouse. Older adults were more lateralized on a handedness test than young adults and were less efficient using their nonpreferred hand. With practice, older adults improved their response time more than other age groups did. The mouse was rated as more acceptable and easier to use than the light pen across trials, despite the performance advantage of the light pen for all age groups. Usability ratings correlated moderately with performance. A benefit-cost analysis indicated that the more efficient light pen might cover its greater initial cost within 11 months for an older adult and within 23 months for a younger adult. Actual or potential applications of this research include advising older adults to persist with practice for new input devices, advising those who must switch to their non-preferred hand to select a direct positioning device, and providing a methodology for determining the potential payback interval when switching to a faster, though more expensive, input device.     

Age differences in trust and reliance of a medication management system

The present study examined age differences in trust and reliance of an automated decision aid. In Experiment 1, older and younger participants performed a simple mathematical task concurrent with a simulated medication management task. The decision aid was designed to facilitate medication management, but with varying reliability. Trust, self-confidence and usage of the aid were measured. The results indicated that older adults had greater trust in the aid and were less confident in their performance, but they did not calibrate trust differently than younger adults. In Experiment 2, a variant of the same task was used to investigate whether older adults are subject to over-reliance on the automation. Differences in omission and commission errors were examined. The results indicated that older adults were more reliant on the decision aid and committed more automation-related errors. A signal detection analyses indicated that older adults were less sensitive to automation failures. Results are discussed with respect to the perceptual and cognitive factors that influence age differences in the use of fallible automation.     

Eye movements of younger and older drivers.

This 2-part study focuses on eye movements to explain driving-related visual performance in younger and older persons. In the first task, participants' eye movements were monitored as they viewed a traffic scene image with a numeric overlay and visually located the numbers in their sequential order. The results showed that older participants had significantly longer search episodes than younger participants, and that the visual search of older adults was characterized by more fixations and shorter saccades, although the average fixation durations remained the same. In the second task, participants viewed pictures of traffic scenes photographed from the driver's perspective. Their task was to assume the role of the driver and regard the image accordingly. Results in the second task showed that older participants allocated a larger percentage of their visual scan time to a small subset of areas in the image, whereas younger participants scanned the images more evenly. Also, older participants revisited the same areas and younger participants did not. The results suggest how aging might affect the efficacy of visual information processing. Potential applications of this research include training older drivers for a more effective visual search, and providing older drivers with redundant information in case some information is missed.     

Faces and Pictures: Understanding age differences in two types of graphical authentications

Recall of knowledge-based authentication codes such as passwords and PINs can be problematic, particularly for older adults given the known memory decline associated with ageing. We explored the extent to which recognition-based Graphical Authentication Systems were effective alternatives to PINs and passwords in a study in which users were asked to commit several different codes to memory and recall them at different time periods. Populations of younger and older adults were given face-based and picture-based authentication codes to remember over the course of three weeks. Results show a pronounced age effect, with younger participants outperforming older participants. Older participants fared better with the face-based system over the picture-based system while younger participants exhibited the opposite effect. A significant performance drop was observed for older participants over time, as additional codes were introduced.     

Multimodal feedback: an assessment of performance and mental workload

Multimodal interfaces offer great potential to humanize interactions with computers by employing a multitude of perceptual channels. This paper reports on a novel multimodal interface using auditory, haptic and visual feedback in a direct manipulation task to establish new recommendations for multimodal feedback, in particular uni-, bi- and trimodal feedback. A close examination of combinations of uni-, bi- and trimodal feedback is necessary to determine which enhances performance without increasing workload. Thirty-two participants were asked to complete a task consisting of a series of 'drag-and-drops' while the type of feedback was manipulated. Each participant was exposed to three unimodal feedback conditions, three bimodal feedback conditions and one trimodal feedback condition that used auditory, visual and haptic feedback alone, and in combination. Performance under the different conditions was assessed with measures of trial completion time, target highlight time and a self-reported workload assessment captured by the NASA Task Load Index (NASA-TLX). The findings suggest that certain types of bimodal feedback can enhance performance while lowering self-perceived mental demand.     

Does training in the cold improve cold performance?

Despite the well-described physiological response to cold, little is known about how to best train persons to perform motor tasks in cold conditions. It is unclear if principles of training specificity would apply to motor skill training when cold because cold exposure reduces tactile sensitivity and cognitive function, which may reduce rather than enhance training efficacy. The purpose of this study is to determine whether training in the cold facilitates performance in the cold. To do this, we investigated the effect of cold or thermoneutral training on performance of the Grooved Pegboard Task. Twenty persons (11M, 9F, mean age 31.2 ± 5.44 years) visited the lab on two separate days and were randomly assigned to either a cold (5M, 5F) or thermoneutral (6M, 4F) training group. On day one, participants were tested at baseline and then performed 20 repetitions of the task according to their respective group assignment. Prior to each task repetition during training, the cold training group immersed their hand in cold water (2 °C) while the thermoneutral group immersed their hand in thermoneutral water (34 °C). Following training, participants were tested once again (immediate retention test). During testing, participants performed the task twice; once after immersing their hands in cold water and once after immersing their hands in thermoneutral water. On day two, delayed retention tests were performed. Time to completion and number of errors were recorded during testing. There were no differences in time to completion at delayed retention tests between thermoneutral and cold-trained groups (p = 0.434). The incidence of errors was significantly less in the cold-trained group than the thermoneutral training group at delayed retention testing (p = 0.035). The main finding of this study was that dexterity but not speed was improved by cold training. Further research is required but the findings presented here suggest that industries that require motor tasks in the cold could benefit from training employees in cold conditions.     

Multimodal feedback: an assessment of performance and mental workload

Multimodal interfaces offer great potential to humanize interactions with computers by employing a multitude of perceptual channels. This paper reports on a novel multimodal interface using auditory, haptic and visual feedback in a direct manipulation task to establish new recommendations for multimodal feedback, in particular uni-, bi- and trimodal feedback. A close examination of combinations of uni-, bi- and trimodal feedback is necessary to determine which enhances performance without increasing workload. Thirty-two participants were asked to complete a task consisting of a series of ‘drag-and-drops’ while the type of feedback was manipulated. Each participant was exposed to three unimodal feedback conditions, three bimodal feedback conditions and one trimodal feedback condition that used auditory, visual and haptic feedback alone, and in combination. Performance under the different conditions was assessed with measures of trial completion time, target highlight time and a self-reported workload assessment captured by the NASA Task Load Index (NASA-TLX). The findings suggest that certain types of bimodal feedback can enhance performance while lowering self-perceived mental demand.     

Influences of general computer experience and age on library database search performance

Two experiments examined the effects of general computer experience and age on library system search performance among novice library system users. Twenty younger adults (10 with high and 10 with low computer experience) and 20 older adults (10 with low and 10 with no computer experience) performed 10 search tasks of varying difficulty. Search success, syntax errors, database field specifications, keyword specifications, and use of Boolean operators were examined. Among younger novices, high computer experience was associated with slightly better performance than low computer experience. Among older novices, having some computer experience was associated with much better performance than no computer experience. Older computer users showed lower overall success rates, made more syntax and field specification errors, and demonstrated poorer understanding of Boolean logic and keyword matching algorithms than younger adults with similar computer experience. Implications for interface design and training interventions for novice on-line library system users are discussed.     

Effects of four types of non-obtrusive feedback on computer behaviour, task performance and comfort

This study investigated the effects of non-obtrusive feedback on continuous lifted hand/finger behaviour, task performance and comfort. In an experiment with 24 participants the effects of two visual and two tactile feedback signals were compared to a no-feedback condition in a computer task. Results from the objective measures showed that all types of feedback were equally effective to reduce lifted hand/finger behaviour (effectiveness) compared to absence of feedback, while task performance was not affected (efficiency). In contrast to objective measures, subjective user experience was significantly different for the four types of feedback signals. Continuous tactile feedback appeared to be the best signal; not only the effectiveness and efficiency were rated reasonable, it also scored best on perceived match between signal and required action. This study shows the importance of including user experiences when investigating usability of feedback signals. Non-obtrusive feedback embedded in products and environments may successfully be used to support office workers to adopt healthy, productive and comfortable working behaviour.     

Task frequency as a function of age for the powerline technician trade

It is traditionally believed that worker productivity declines with age. The greatest contributor to this stereotype, particularly in physically demanding jobs, is that older workers can no longer maintain their sustained level of work due to the age-associated decline in physical capacity. The objective of this study was to determine the change in the frequency of task performance as a function of age in the power line technician (PLT) trade. The task requirements of the PLT occupation were determined through the use of a detailed job demands analysis (JDA) and the frequency at which these tasks were performed was acquired through a survey derived from the JDA. The results of the survey were assessed as a function of age. Older lineworkers (> or = 50 years) were found to spend more time working on the ground whereas the younger PLTs (< or = 39 years) more frequently performed the climbing tasks and the corresponding work on the poles and towers. In contrast the older PLTs performed all pushing/pulling tasks at a greater or equal frequency to that of the younger lineworkers. Despite these differences the frequency of task performance is similar across the age groups studied.     

Do in-vehicle advanced signs enhance older and younger drivers’ intersection performance? Driving simulation and eye movement results

An experimental study was conducted to determine if intersection behaviour benefited from advanced in-vehicle signs presented to older and younger drivers in a head-up display (HUD) format. The University of Calgary Driving Simulator (UCDS) was used to evaluate intersection performance. Measures of those who were able to stop or ran the yellow light, speed over the span of the intersection, perception response time, and eye movements were analyzed to determine if performance improved or whether undesirable adaptive behaviours occurred. In-vehicle signs facilitated an increase in the frequencies of stopping for both younger and older drivers at intersections with relatively short yellow onsets. The speed at the yellow light onset for both those who stopped and those who proceeded through the intersection was reduced by the presence of the in-vehicle signs. The primary behavioral influence of the in-vehicle signs was to cause the drivers’ to reduce their velocity in advance of an intersection. Eye movement analyses indicated that younger drivers looked at the in-vehicles signs more often and for longer overall durations than older drivers. Older drivers had slower intersection approach speeds, stopped more accurately, and were more likely to not clear the intersection before the traffic light turned to an all-red phase than younger drivers. The implications of the in-vehicle sign results are discussed in terms of in-vehicle information systems (IVIS) design guidelines and evaluation methods.     

Age-related performance in a multiple-task environment.

Younger and older adult participants performed a dynamic multiple-task requiring concurrent processing of 4 independent tasks. Component-task performance emphasis (i.e., task priorities) was biased by differential point allocations across task components. After training, the point structure was modified. Older adults exhibited larger multiple-task performance deficits compared with younger adults; however, the age-related gap in multiple-task performance decreased with practice. The age-related performance difference increased again when task emphasis was changed, but not when demands were changed. Consistent with the training data, the age-related differences diminished again with additional experience on this new task-component emphasis. The data suggest that higher-order, strategic processing may be an important source of age-related differences in complex multiple-task performance. Actual or potential applications of this research include the facilitation of techniques for age-related comprehensive usability testing for products of even moderate complexity.     

Task frequency as a function of age for the powerline technician trade

It is traditionally believed that worker productivity declines with age. The greatest contributor to this stereotype, particularly in physically demanding jobs, is that older workers can no longer maintain their sustained level of work due to the age-associated decline in physical capacity. The objective of this study was to determine the change in the frequency of task performance as a function of age in the power line technician (PLT) trade. The task requirements of the PLT occupation were determined through the use of a detailed job demands analysis (JDA) and the frequency at which these tasks were performed was acquired through a survey derived from the JDA. The results of the survey were assessed as a function of age. Older lineworkers (? 50 years) were found to spend more time working on the ground whereas the younger PLTs (? 39 years) more frequently performed the climbing tasks and the corresponding work on the poles and towers. In contrast the older PLTs performed all pushing/pulling tasks at a greater or equal frequency to that of the younger lineworkers. Despite these differences the frequency of task performance is similar across the age groups studied.     

Environmental support hypothesis in designing multimedia training for older adults: Is less always more?

This study explores younger and older adults learning of MS Publisher functionalities from a multimedia tutorial. Twenty younger and twenty three older adults assigned to a redundant (experimental) or non-redundant (control) condition were taught how to create a greeting card, while the results of their learning were assessed with immediate and delayed performance measures. While younger learners benefited from a non-redundant condition, older learners exhibited an opposite trend. Redundant condition was beneficial for their performance efficiency on a set of a transfer tasks, and their troubleshooting performance during the delayed session. From a cognitive load perspective, using a redundant text along with an audio narration overloads learner’s working memory by placing more strain on the visual pathway and not providing any additional cognitive advantage. From an environmental support standpoint and decreased processing resources view of cognitive aging, providing additional representational support helps reducing the task demands for older adults and results in better learning. The results have cognitive and practical implications for the design of multimedia learning environments for older adults.     

Reading in the dark: effects of age and contrast on reading speed and comprehension

OBJECTIVE: To explore the effects of contrast reduction on younger and older adults' reading behavior and to examine whether readers rely on word predictability to compensate for poor contrast. BACKGROUND: Poor contrast can degrade text and may influence reading behavior. Readers may compensate for visual degradation of text by taking advantage of word predictability. METHOD: In Experiment 1, 5 younger and 5 older adults read sentences presented with 10 levels of contrast. In Experiment 2, 40 younger and 40 older adults read high-, medium-, and low-contrast sentences that varied in target word predictability (high vs. low). RESULTS: Relative to those of younger adults, older adults' reading rates were more slowed by low contrast; comprehension was less influenced by contrast (i.e., not significantly). Older adults read high-predictability words faster and comprehended them better than low-predictability words, significantly so for high- and medium-contrast sentences. Younger adults comprehended high-predictability words significantly better than low-predictability words for high- and low-contrast sentences. CONCLUSION: Low contrast was more detrimental for older adults. High-predictability words benefited older adults by significantly reducing their reading times and benefited all readers by significantly increasing their comprehension. APPLICATION: The current findings demonstrate the benefit of adequate contrast and word predictability for optimal text design to facilitate both reading times and reading comprehension.