Contrasting episodic and template-based guidance during search through natural scenes

Visual search through natural scenes can be guided by knowledge of where a target object has been observed previously (episodic guidance) and knowledge of that object's visual properties (template guidance). In the present experiments, we compared the relative contributions of these two sources of guidance. Episodic guidance was implemented in a contextual cuing task: participants searched multiple times through a set of scenes for a target letter that appeared in a consistent location within each scene. Template guidance was implemented by the color match between a critical distractor in each scene and a secondary visual working memory (VWM) load. There were four main findings. First, search time decreased with increasing scene repetition; episodic memory guided search. Second, the critical distractor was fixated more frequently on match compared with mismatch trials, consistent with automatic template guidance. Third, the VWM-match effect persisted in blocks with strong episodic guidance. Finally, VWM-match effects were observed from the first saccade during search, whereas episodic guidance to the target developed only later in the trial. The results support a view of natural search in which template-based mechanisms operate early during search in a manner that is not strongly constrained by scene-based forms of guidance, such as episodic knowledge. (PsycINFO Database Record (c) 2019 APA, all rights reserved).