Expertise studies in the medical domain often focus on either visual or cognitive aspects of expertise. As a result, characteristics of expert behaviour are often described as either cognitive or visual abilities. This study focuses on both aspects of expertise and analyses them along three overarching constructs: (1) encapsulations, (2) efficiency, and (3) hypothesis testing. This study was carried out among clinical pathologists performing an authentic task: diagnosing microscopic slides. Participants were 13 clinical pathologists (experts), 12 residents in pathology (intermediates), and 13 medical students (novices). They all diagnosed seven cases in a virtual microscope and gave post hoc explanations for their diagnoses. The collected data included eye movements, microscope navigation, and verbal protocols. Results showed that experts used lower magnifications and verbalized their findings as diagnoses. Also, their diagnostic paths were more efficient, including fewer microscope movements and shorter reasoning chains. Experts entered relevant areas later in their diagnostic process, and visited fewer of them. Intermediates used relatively high magnifications and based their diagnoses on specific abnormalities. Also, they took longer to reach their diagnosis and checked more relevant areas. Novices searched in detail, described findings by their appearances, and uttered long reasoning chains. These results indicate that overarching constructs can justly be identified: encapsulations and efficiency are apparent in both visual and cognitive aspects of expertise.