Editors' Introduction and Review: An Appraisal of Surprise: Tracing the Threads That Stitch It Together.

Though the scientific study of surprise dates back to Darwin (), there was an upsurge in interest beginning in the 1960s and 70s, and this has continued to the present. Recent developments have shed much light on the cognitive mechanisms and consequences of surprise, but research has often been siloed within sub-areas of Cognitive Science. A central challenge for research on surprise is, therefore, to connect various research programs around their overlapping foci. This issue has its roots in a symposium on surprise, entitled "Triangulating Surprise: Expectations, Uncertainty, and Making Sense," at the 36th Annual Conference of the Cognitive Science Society (Quebec City, July 2014). Building on the interdisciplinary conversations that started at the symposium, this issue aims to draw attention to some promising empirical and modeling results and their theoretical implications. The present paper sets the stage for the issue by presenting a historical summary, discussing contrasting definitions of surprise, and then by tracing major threads that run through both this issue and the larger literature on surprise. Our aim is to develop broader, shared understandings of the main insights, theories, and findings regarding surprise, with a view to supporting future integration and progress.