A Paired-Object Protocol for Validating Feature Salience in Rodent Exploration: Evidence that Ecology Predicts Which Features Matter

Object-based tasks are widely used in rodent behavioral research, yet object selection remains largely unsystematic. We present a paired-object validation protocol in which objects differ along one researcher-defined feature, allowing assessment of whether that feature is salient to the animal. Using six object pairs varying in height, color, shape, or aperture presence, we tested two wild-caught mice species with contrasting ecologies. Wood mice ( Sylvaemus uralensis ) and striped field mice ( Apodemus agrarius ) showed equal preference for both objects in most pairs, indicating that color, apertures, and apex shape differences are not salient under the tested conditions and can be used interchangeably in object recognition tasks. Height, however, produced ecology-predicted responses: arboreal wood mice avoided the shortest object while open-habitat striped field mice did not. These results demonstrate that the protocol successfully detects feature salience when present and that ecological background predicts which features matter. Summary Statement A systematic paired-object protocol reveals that most researcher-defined features (color, holes, shape) do not affect rodent exploration, but height preferences emerge in ecology-predicted patterns, demonstrating that feature salience is species-specific.