Keep it real, keep it simple: the effects of icon characteristics on visual search

Previous research examining how icons’ concreteness, visual complexity, and distinctiveness influence visual search performance have led to disagreements over which icon characteristic most affects behaviour. These icon characteristics are often poorly defined and interrelated, particularly concreteness. Accordingly, drawing strong inferences about the robustness of concreteness as a factor in search for visual icons is challenging. Here, we operationalised concreteness into three distinct levels: concrete icons were images of real-world objects, photorealistic icons were drawings of the object, and abstract icons were images with no conceptual information. Across two experiments, participants rated each icon on various icon characteristics (e.g. concreteness, visual complexity) to provide a ground truth for these factors and to validate our concreteness manipulation. In a separate study, naive participants performed a visual search task for a target icon. Oculomotor measures were utilised to elucidate how various icon characteristics affected search performance. Although we were unable to fully disassociate concreteness from visual complexity, we found that icons high in concreteness improved search performance, but as visual complexity increased, object identification became slower. This was largely demonstrated through increased verification times for complex targets. The present set of studies indicate that highly concrete and simple icons engender search benefits.