Bundesen's (1990) Theory of Visual Attention (TVA) proposes two attention mechanisms that govern conscious visual perception: Filtering (selection of objects in space) and pigeonholing (selection of visual features). In TVA, the selection of features refers to the specification of response categories (e.g. a feature that is to be reported). Here, we review the relationship between filtering and pigeonholing and discuss the refinements that have been made to them in the past. On this basis, we present new ideas of how filtering and pigeonholing determine conscious visual perception. Last, we provide a roadmap of questions about possible mechanistic relationships of these two attentional mechanisms, and about how we can specify pigeonholing and filtering in more detail that should be addressed in future research.