A systematic review on the effect of individual characteristics and management practices on equine cognition.

Equine cognition is relevant to the many roles that horses serve in society, such as leisure riding, competitions, or even animal-assisted therapy. Equine cognitive abilities have been explored in recent years. However, gaining an overview of horse cognition is challenging due to the broad range of abilities studied and the diverse methodologies employed. In addition, the subjects of existing equine cognition studies vary greatly in contextual factors such as their breed, age, sex, and management conditions - each of which may influence test performance in the following cognitive categories: Discrimination Learning; Learning Sets, Categorisation and Concept Formation; Spatial Cognition; Social Learning; and Memory. The aims of this review were (1) to establish whether contextual information was provided in research articles on horse cognition, (2) to tabulate information on the characteristics, housing, and management of subjects used in different categories of cognitive test, (3) to provide an overview of cognitive abilities demonstrated by horses, i.e., the results obtained in cognitive tests, with a specific emphasis on the contextual factors shaping them. The results of this review highlighted important points for future research. Better reporting of subject characteristics in scientific publications would enable investigation of the factors which shape horses' cognitive abilities, and the use of standardized methods and procedures across studies would facilitate future comparative work.