| Watching TV is one of the favorite daily activities of older adults,but they encountered difficulties in using smart TVs(STVs).According to the results of the previous research,older adults mainly had two problems with STVs using the remote controller: focus manipulation and video searching.To address these two problems,Experiments 1 and 2 explored the solutions to these two problems separately.Furthermore,using the screen-mirroring on smartphones to control STVs might be another possible solutions.Therefore,Experiment 3 explored the difficulty of using Screen-mirroring to control STVs for older adults.The results indicated that an important problem of Screenmirroring was the frequent attention switches,and Experiment 4 explored the solution to this problem.The main contents of the four experiments are as follows:Experiment 1 aimed to improve the performance of focus manipulation for older adults through adjusting the STV interface layout(i.e.maintaining the consistency of the element sizes and adding the arrow hints).48 elderly participants were recruited in this experiment.The results showed that the higher the age of older adults,the longer the time of manipulation focus they used,especially for who over 75 years old;adding arrow hints can help to improve the focus manipulation for who over the age of 75.Regarding the input methods,the performance of using the virtual remote control to manipulate the focus was worse than that of the physical remote control,which can be improved by using the arrow hints.In addition,adding arrow hints also helped when the interface element sizes are inconsistent.Experiment 2 explored the menu design that conformed to the characteristics of STVs and the mental model of older adults.Mega menu and Tiled menu based on labels were designed and 30 elderly participants were recruited to evaluate the menu designs.The results showed that the Mage menu and Tiled menu eased the difficulty of video searching for older adults.Compared to the Tiled menu,the number of keystrokes of the Mega menu for older adults to find videos was lower.However,their satisfaction with the Tiled menu was significantly higher than that with the Mega menu.Experiment 3 investigated the difficulty of the Screen-mirroring to complete five gestures(i.e.dragging,sliding,zooming,drawing and Chinese handwriting entry).14 older adults were recruited and 14 young adults were set up as a control group in this experiment.The results showed that dragging was generally easiest for older adults,which had the highest performance,user satisfaction,and the highest concentration of attention on STV among the five gesture tasks.The problem of the Screen-mirroring was the frequent attention switches between the smartphone and STV screen,especially in the operation which need to confirm the finger position(e.g.tap).To alleviate the problem of the frequent attention switches when older adults use Screen-mirroring,Experiment 4 proposed the way of improving tap method and increasing button sizes.The impacts of tap methods(Direct tap,"Slide + tap" and "Slide + release"),button size on smartphones(8,14,and 20 mm),and input postures(one-hand held and two-hand held)on user performance and feedback were investigated.This experiment recruited 30 older adults.The results showed that the attentional switches of "Slide + tap" and "Slide + release" were less than that of the Direct tap.However,the Direct tap received highest preference and the "Slide + tap" received lowest preference by older adults.Additionally,the performance of the tap task for older adults using the one-hand posture was lower than that using the one-hand posture.The way to mitigate the performance degradation of one-hand held posture was to increase the size of the smartphone button;using 8 mm button size under Screen-mirroring method with onehand held posture had 40.7% more task completion time than that using 14 mm.The results of this study based on experiments can provide TV practitioners with interaction design guidelines of Smart TVs for older adults. |
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