Abstract: With two experiments, using the dual-task paradigm, this paper discussed the influence of matching degree of task-set and stimuli's property towards the pattern of feature search. Participants were required to identify the unique letter in the stream of Arabic numerals (T1), and then completed a feature search task (T2). In experiment 1, T2 was to detect a red dot among grey distractors. In experiment 2, grey distractors were replayed by multiple colored dots. The results reveal that the pattern of feature search cannot be influenced by the matching degree of task-set and stimuli's property, no matter the feature search is primarily guided by bottom-up information or top-down information. According to these results, it is suggested that detection of a specific feature is executed in a parallel pattern with high efficiency after task-switch is completed, rather then in a serial pattern with low efficiency while task-switch was uncompleted.

Key words: feature search, task switch, guided search model, dynamic control theory