Worth a quick look? Initial scene previews can guide eye movements as a function of domain-specific expertise but can also have unforeseen costs

Rapid scene recognition is a global visual process we can all exploit to guide search. This ability is thought to underpin expertise in medical image perception yet there is no direct evidence that isolates the expertise-specific contribution of processing scene previews on subsequent eye movement performance. We used the flash-preview moving window paradigm (Castelhano & Henderson, 2007) to investigate this issue. Expert radiologists and novice observers underwent 2 experiments whereby participants either saw a 250ms scene preview or a mask before searching for a target. Observers looked for everyday objects from real-world scenes (Experiment 1), and searched for lung nodules from medical images (Experiment 2). Both expertise groups exploited the brief preview of the upcoming scene to more efficiently guide windowed search in Experiment 1, but there was only a weak effect of domain-specific expertise in Experiment 2, with experts showing small improvements in search metrics with scene previews. Expert diagnostic performance was better than novices in all conditions but was not contingent on seeing the scene preview, and scene preview actually impaired novice diagnostic performance. Experiment 3 required novice and experienced observers to search for a variety abnormalities from different medical images. Rather than maximising the expertise-specific advantage of processing scene previews, both novices and experienced radiographers were worse at detecting abnormalities with scene previews. We discuss how restricting access to the initial glimpse can be compensated for by subsequent search and discovery processing, but there can still be costs in integrating a fleeting glimpse of a medical scene