ニオイ発生源の定位における探索行動に関する検討

摘要

本論文では，人間のニオイの発生源探索行動に関する実験について報告した.日常生活の中で私たちは，ニオイのする方向を向く，ニオイのする方に鼻(頭部)を近づける，といった行動により，ニオイの発生源を定位するが,その探索行動を系統的に検討した研究は少ない.本稿では，実験参加者にテーブル上(2次元平面)に配置されたニオイ発生源を探索させ，その時の呼吸および身体上部の動きを分析した.探索時の行動には，ある場所から「嗅ぎ始め」，ニオイがありそうな範囲を「絞り込み」，最終的にニオイの位置を「決定する」という共通した過程が認められたとともに，全体を嗅ぎ回る，範囲を限定して嗅ぐなど個人間の探索方略の差異も観察された.また嗅ぎ始めに上半身を左右に大きく揺れ動かして探索する方略は，環境中における気流の状態を変え，ニオイガスを周辺に拡散させることにつながるために，正しい定位には適切ではない可能性も示唆された.%In this study, searching behavior in odor localization in human was investigated. In order to search the source of the odor, we turn our heads or approach the direction of the presumed source in everyday life. However, there are few reports that have systematically examined the behavioral processes of localization of odor source. In this experiment, participants identified the positions of odor sources placed on the table (two-dimensional plane), and their respiratory cycle and movement of the upper part of the body during searching behavior were recorded. As results, a series of behavioral process was commonly observed among all participants; first, participants began smelling from the particular place, then started to search around and focused on the limited area where the odor source is presumed to be, and finally decided on the direction of the odor source. The strategies of the participants when they were focused on searching for the odor differed with each other. Although a successful strategy was not found, moving the upper part of the body at the beginning of sniffing was not effective because this action caused a change of airflow surrounding participants and diffused the trails of odor.