針對高齡使用者之WWW介面設計

Abstract

本研究的目的是從高齡者感官、生理及認知上的衰退，探討其使用輸出入機制、網頁介面設計元素的WWW瀏覽表現及態度，以提昇高齡者的人機表現。研究者發展出一套概念模型，用以表達感官、生理及認知上的衰退，輸出入機制、網頁介面設計元素，使用性問題之間的關聯。這些元素發展出本研究的研究架構、研究假設和實驗系統之設計。 實驗前測首先驗證文獻探討所提的設計準則，三位年輕使用性專家以啟發式評估法，及八位實際高齡使用者使用放聲思考法，針對兩家知名中文新聞網站首頁進行評估，結果發現關於先前文獻所探討的是明確且肯定的。因此網頁設計者可依循本研究所提出的設計準則進而改善對高齡者的網頁使用性。 實驗一的目的旨在檢驗直接與非直接輸入機制對高齡使用者瀏覽網頁的影響。該實驗採用單因子設計，依變項為使用者之表現時間、學習效果、錯誤率、滿意度、迷失程度及心智負荷程度。實驗一參與者招募50歲以上高齡自願者共計24名，隨機分派至觸控組、語音組與滑鼠組，實驗過程中以電腦紀錄參與者在瀏覽任務上的表現及紙筆問卷測量。 實驗二的目的旨在檢驗直接與非直接輸入機制對高齡使用者關鍵字搜尋網頁的影響。該實驗採用單因子設計，依變項為使用者之表現時間、學習效果、錯誤率、滿意度、迷失程度及心智負荷程度。參與者同實驗一共計23名，隨機分派至觸控+手寫組、語音組與滑鼠+鍵盤組，實驗過程中以電腦紀錄參與者在瀏覽任務上的表現及紙筆問卷測量。 實驗三的目的旨在比較有無聽覺輔助輸出機制對高齡者瀏覽網頁的影響。該實驗採用重複測量設計及多階因子實驗設計，依變項為使用者之表現時間、記憶力、理解力、滿意度及迷失程度。實驗的參與者招募50歲以上高齡自願者共計16名，參與者隨機分配至有無語音文字兩組，每一參與者須進行有無語音選單兩次實驗。實驗過程中以電腦紀錄參與者在瀏覽任務上的表現，離線紙筆之記憶力、理解力測驗和態度問卷。 實驗一結果顯示，輸入機制對瀏覽表現的「表現時間」、「學習效果」與心智負荷面向之「挫折程度」有顯著影響。整體而言，直接操控輸入機制對於高齡者在表現時間上的確優於非直接操控輸入機制。 實驗二結果顯示，以關鍵字搜尋任務而言，利用直接操控輸入機制(手寫辨識機制或是語音)輸入關鍵字，都比利用非直接操控輸入機制(鍵盤)的表現時間佳。 實驗三結果顯示，有無提供綜合語音文字的聽覺輔助輸出機制對高齡使用者的表現時間有顯著影響，提供綜合語音文字會比未提供綜合語音文字來得較無效率。 整體而言，提供觸控或是語音等直接操控輸入機制的情況下，高齡參與者瀏覽網頁的表現優於使用滑鼠的非直接操控輸入機制。此外，提供提供觸控+手寫或是語音等直接操控輸入機制的情況下，高齡參與者使用搜尋引擎搜尋網頁的表現優於使用滑鼠+鍵盤的非直接操控輸入機制，因此，提供多樣化的輸入機制可以幫助高齡者減少學習滑鼠及鍵盤輸入的時間，而能更有效率地使用WWW找到想要的資訊。

The purpose of this study is to investigate the decreases in the physical, sensorial, and cognitive ways for older adults, and to check whether the I/O mechanism and the elements of web interface design would influence their performance and attitude toward the browsing of WWW. We develop a conceptual model to express the decreases in the physical, sensorial, and cognitive ways for older adults and to show the relationship of the I/O mechanism, the elements of web design and usability problems. Based on these elements, we develop the structure, hypotheses, and experiments of this study. We firstly examine guidelines from literature review. Specific design improvements and general design guidelines for older WWW users are discussed. Three young usability experts have evaluated the homepages of the two well-known Chinese news websites by using the methods of heuristic evaluation and eight-older-user think aloud. The general agreement with the literature lends support to the notion that our findings are firm and general. We believe that Web page designers can improve the usability of Chinese web pages by applying the guidelines proposed in this study. The purpose of Experiment I is to compare the influences that the direct and indirect input mechanisms may have on older participants when they use either to browse WWW. We adopt one factor design. The dependences are performance time, errors, satisfaction, lost, and mental workload. Twenty-four voluntary participants, who are over 50 years old, are recruited and dispatched randomly to one of the three groups, including the touch, voice, and mouse groups. In the process, the data were automatically recorded by the computer and questionnaires. The purpose of Experiment II is to compare the influences that the direct and indirect input mechanisms have on older participants when they use either to search WWW. One factor design is adopted. The dependences are performance time, errors, satisfaction, lost, and mental workload. Twenty-three participants are recruited and dispatched randomly to one of the three groups, including touch & written, voice, and mouse & keyboard groups. In the process the data were automatically recorded by the computer and questionnaires. The purpose of Experiment III is to compare the influence that the audio assignment output mechanism may have on older participants when they use it or don’t use it to browse WWW. Repeated-measures design and nested-factorial experiments are adopted. The dependences are performance time, memory, comprehension, satisfaction, and lost. Sixteen participants are recruited and dispatched randomly to either of the video and audio groups. In the process, the data were automatically recorded by the computer and questionnaires. The results of three experiments can be summarized into the following findings: n Direct input device significantly outperformed indirect input device on “performance time”, “learning effect”, and “frustrated level” in browsing task. n Direct input device significantly outperformed indirect input device on “performance time”, “learning effect” in keyword searching task. n Audio output device significantly outperformed input device on “performance time”, “learning effect” in keyword searching task. The results indicate that, in general, direct input devices are useful for older adults in browsing and keyword searching in WWW system.