Abstract
When searching for objects in naturalistic scenes, humans rely strongly on their previously acquired knowledge about the environment – their “scene grammar”. While allowing for incredibly efficient search, the activation of scene grammar seems to require some time characterized by a substantial decrease in response times occurring between the first and second search within an environment. This Search Initiation Effect (SIE) is followed by little additional decrease in subsequent searches. Our study focused on uncovering the cognitive processes leading to this ubiquitous search efficiency profile. We used a visual search flashlight paradigm in virtual reality, in which participants could not see the full room during search but were equipped with a “flashlight” restricting the view to the illuminated parts of the room. We manipulated scene memory and the need to orient oneself, i.e., either participants entered a room and immediately started searching for objects (no preview, need to orient oneself), or they received a preview of the room in full light for 10 seconds just before search initiation (preview, no need to reorient oneself), or they received the same preview as in the preview condition but entered an empty gray room for 5 seconds before reentering the search room to start searching (preview with interruption, need to reorient oneself). Preliminary results suggest that only the preview without interruption erased the SIE implying that the availability of scene memory alone cannot circumvent the need to activate scene grammar, since the SIE was still evident when participants acquired knowledge about the room in the preview with interruption condition. Rather, our results indicate that activation of scene grammar is necessary to efficiently search even when reentering a familiar room. We will further analyze additionally collected eye tracking measures to investigate when, where, and how search initialization takes place and influences search behavior.