空間巡行能力包括能夠辨識起點與終點、決定該走哪條路、以及辨認路上的地標，視覺訊息是人類在空間巡行能力中所仰賴的主要訊息類別之一，因此能夠再認與有效利用地標便成為一項重要的能力。由於虛擬實境能提供受試者足夠的視覺刺激產生移動覺，適合在實驗室中使用，搭配嚴謹的實驗程序控制，近年來在探討人類空間巡行能力之實驗中已廣泛被應用。本研究利用虛擬實境場景探討人類在複雜且不規則結構環境中，使用全域性地標及局部性地標來幫助形成空間表徵之效果是否有所差異，並試圖釐清造成該差異之真正原因。實驗一中，受試者分別執行全域性地標呈現、局部性地標呈現以及無地標呈現之三類實驗情況，受試者必須藉由實驗環境中可使用的地標來學習目標物所在的位置，透過在測試階段中受試者尋找目標物所需花費的時間、所行走的距離總和以及表現達到表現標準的所需學習次數反映受試者在不同實驗情況中的空間表徵形成完整性。實驗結果發現受試者在複雜結構環境中，局部性地標使受試者的表現顯著地優於在其他兩個實驗環境中的表現，而全域性地標並未使受試者的表現優於無地標呈現環境。實驗二、三、與四分別利用實驗操弄探討造成此項差異的原因是否是來自於受試者天生傾向使用某種空間表徵(自我中心或他物中心)，或是因為不同的地標恰巧有助於人類形成不同類型的空間表徵，或是由於複雜不規則的環境結構阻擋路徑而致使受試者在使用全域性地標時無法有良好表現。實驗五將以腦電波技術探討人類在執行空間巡行作業時所運用的腦部區域。 總結而言，所有的實驗都顯示局部性地標確實能在不規則環境中最有效地提升人們的空間巡行表現，但在經過較長時間的練習之後，全域性地標同樣也能使人類表現提升。關於造成這兩項地標貢獻不同的可能原因，目前已經初步排除了幾項：人類使用空間表徵的偏好、不同類型地標導致不同類型空間表徵形成的容易度、以及環境結構規則度、複雜度的影響。至於真正的原因仍有待未來更多研究的釐清與探討。 The ability to recognize and use object landmarks is crucial for efficient wayfinding. However, the roles of different types of landmarks in wayfinding remain to be clarified. In the current study, we examined how global and local landmarks are utilized differentially in novel virtual maze environments, and aimed to clarify the causes of these differences. Three different experimental conditions were constructed: first, a global object landmark condition consisted of a virtual maze surrounded by high-rise architectures visible from almost everywhere inside; second, a local object landmark condition consisted of a virtual maze with cartoon pictures of common objects only visible from certain locations posted on some walls along the paths inside; finally, a control condition consisted of a virtual maze without any object landmarks. The participants learned the layout of the environment and the target positions through a series of learning trials. Their learning performance was assessed by traveling distance, time, and ratio of successfully found targets within time limits. The results of Experiment 1 demonstrated that participants learned to navigate most efficiently in the local landmark condition, while their performance did not differ between global and control conditions. Experiment 2, 3 and 4 aimed to verify these differences were caused by natural tendency of using different spatial representations, by different spatial representation using when different landmarks were available, or by the influence of the irregular geometric structures, respectively. Experiment 5 aimed to explore the neural mechanism when people performing wayfinding task with these object landmarks with electroencephalography. In conclusion, both local and global object landmarks could benefit people’s wayfinding behavior, but it takes a longer period of time for using global landmarks to reach the optimal performance. Natural tendency of using spatial representation, accessibility to different spatial representations, and regularity of geometric structures have been preliminarily ruled out. Further studies are needed to clarify the actual mechanisms underlying the differences in performance between the global and the local landmarks.
