Rethinking attention: A unified perspective on top-down and bottom-up processes

Attention enables organisms to prioritize information in environments where neural and cognitive resources are limited. Traditionally, this process has been understood as the outcome of two distinct mechanisms: top-down control, shaped by goals and expectations, and bottom-up reactivity to salient stimuli. However, growing evidence from neuroscience, psychology, and evolutionary theory challenges the clarity and sufficiency of this dichotomy. This review proposes a unified framework in which attentional selection emerges from a single system guided by overlapping priorities across three timescales: evolutionary imperatives (e.g., survival), learned experiences (e.g., value-based biases), and immediate task demands. Rather than two interacting systems, top-down and bottom-up processes are reinterpreted as different temporal expressions of the same underlying mechanism. This perspective offers a reconceptualization of classical models and encourages a more integrated interpretation of neural and behavioral data.