Investigating The Effects Of Touch Gestures On Click Performance And Fatigue Of Using Smart Phones

In daily life,people will interact with smart phones by touch,such as clicking,sliding,zooming,because this interaction process is easy to be affected by various factors,there will be many problems,such as young people have a higher risk of hand muscle injury in high frequency smart phones use,and the elderly are prone to mis operation during touch interaction.Therefore,it is important to understand how touch interaction is affected.It can help designers better understand touch interaction,solve the problems of touch interaction in daily life,and improve user interaction experience.In this study,three factors influencing touch interaction were selected: operation gesture,screen size,touch gesture.Three experiments were designed and implemented to explore the influence of these three factors on touch interaction.Firstly,the impact of operation gestures on click performance and fatigue was studied,a total of 28 young people was recruited to participate in the experiment.Secondly,the impact of operation gestures and screen size on click performance and fatigue was studied,a total of 23 young people was recruited to participate in the experiment.Finally,the performance of different touch gestures was studied,40 old people were recruited to participate in the experiment.Research on the effect of operation gestures on click performance and fatigue showed that young subjects have a longer task complete time in one-handed operation than two-handed operation.In terms of fatigue,the short abductor pollicis brevis muscle(APB)is more fatigued in one-handed operation than two-handed operation,and regardless of one-handed or two-handed operation,the fatigue of APB is higher than that of the first dorsal interosseous muscle(FDI).In addition,in one-handed and two-handed operation,the areas of high deviation on the screen are concentrated on the edge of the screen.Research on the effects of hand gestures and screen size on click performance and fatigue showed that regardless of the one-handed or two-handed operation,the click deviation on the 5.5-inch screen is higher than 5.0 inches,regardless of the screen size of5.0 or 5.5 inches,the one-handed operation clicked deviation is higher than two-handed operation;the task completion time of one hand operation was longer than that of twohanded operation,the task completion time on the 5.5-inch screen is longer than that on the 5.0-inch screen.In terms of fatigue,the fatigue of APB and FDI in one-handed operation is higher than that of two-handed operation,and the fatigue of APB is higher than that of FDI no matter one handed or two-handed operation.In addition,when operating with one hand or two hands,there is a vertical deviation area on the left edge of the screen in the click deviation vector field of both screen sizes,and the direction of the deviation vector in the area is to the right;when operating with two hands,there is a horizontal deviation area on the edge of the thumb activity range in the middle of the screen,and the direction of the deviation vector in the area is down.Research on the performance of touch gestures and model fitting showed that: in terms of touch performance,compared with the preset task difficulty of 4,when the difficulty is 2,the movement time of clicking,dragging,zooming and rotating is shorter and the success rate is higher.In terms of model fitting,the fits of the traditional Fitts model in click,drag,zoom,and rotate are 30%,22%,51%,and 31%,respectively,after the model correction in the drag gesture,the fitting degree is increased to 72%.These fitting results showed that Fitts’ law has defects in describing the touch gestures of elderly subjects.Regarding the behavior mode of touch gestures,elderly subjects’ touch point on the screen always to the right of the target center when clicking with index finger;when the elderly subjects drag with the index finger,they will first drag the target to near the preset position,then adjust its position;in the zoom and rotate gestures,the elderly subjects usually keep one finger still and other finger to move to control the zoom and rotation.This research explored how touch interaction is affected by operation gesture,screen size and touch gesture,and summarized the applicable touch interaction behavior rules under certain conditions,which can provide reference criteria for the design of touch interaction interface of smart phones,so as to solve common touch interaction problems.