顯示畫面大小對老年人視覺搜尋作業之影響

Abstract

目前的顯示器設計準則多針對年輕人與約15度視角大小顯示器，卻未必適用於老年人與不同大小的觀看環境。本研究採用視覺搜尋實驗典範，以老年人為對象，年輕人為對照組，改變顯示畫面大小(單位為視角)，探討顯示畫面大小對老年人視覺搜尋作業之影響。本研究包含三個實驗。實驗一請老年人在三種顯示畫面(16度、32度、60度視角)中進行視覺搜尋作業。結果發現搜尋類型與項目數目的顯著效果與交互作用，但顯示畫面大小的效應卻不強健。實驗二與實驗三請年輕人與老年人在三種搜尋範圍大小(8度、16度、32度視角)中進行視覺搜尋作業，實驗二中項目大小隨搜尋範圍縮小而等比縮小，實驗三中項目大小則不改變。結果，實驗二中，年輕人與老年人在16度、32度視角情況中的表現型態與實驗一相似，亦出現年齡、項目數目與搜尋範圍大小的顯著效果與交互作用。實驗三中，8度、16度情境的項目尺寸不縮小，搜尋效率相較於實驗二有顯著的促進。同時，老年人在平行式搜尋情境中，反應時間不隨項目數目與搜尋範圍大小而增加。序列式搜尋情境中，反應時間則顯著隨著項目數目的增加而增加，搜尋效率亦隨著搜尋範圍縮小而促進，但由16度縮小到8度時促進幅度卻變小。可能是項目之間擁擠程度增加而導致。因此本研究結果支持年齡、搜尋範圍大小、搜尋類型、項目數目、項目大小與擁擠程度等變項對視覺搜尋表現皆有影響。

Current knowledge about attention is largely based on data obtained with young adults using devices of moderate display size. With the aging of increasingly large populations and the advance of dis¬play technology, comes the need for understanding the elderly’s attention behavior over a wider range of viewing sizes. The effect of display size on the elderly’ visual search performance was studied in three experiments. In exp. 1, the elderly performed two types of visual search tasks, that is, parallel and serial search, under three display-size conditions (16°, 32°, and 60°). Elderly’ reaction time increased with set size in serial, but not parallel search. However, the display size effect was not robust. In exp. 2 and 3, the elderly and the young control engaged in the same tasks in 8°, 16°, and 32° display size conditions. In exp. 2, the item size was scaled with the display size. The elderly’s performance replicated that in exp. 1 roughly, and it took them more time to complete a task than the young. In exp. 3, the item size was held constant. The elderly’s serial, but not parallel search was affected by the display size. In the serial task, the reaction time for detecting a target decreased with the display size from 32° to 16°, and then remain constant down to 8° condition, suggesting that some sort of crowding effect was in action. To sum up, this study shows that age, display size, search type, set size, item size, and crowding all affect visual search performance.