Donald Broadbent (1926-1993) was a pioneering British cognitive psychologist whose filter theory of attention (1958) was one of the first information-processing models in psychology and helped launch the cognitive revolution. His work demonstrated that the human mind could be studied as an information-processing system with measurable capacities and limitations, providing a scientific alternative to both behaviorist and introspectionist approaches.
Filter Theory
Broadbent's filter theory, presented in Perception and Communication (1958), proposed that the nervous system acts as a single communication channel with limited capacity. A selective filter, operating on physical characteristics of the input (location, pitch, loudness), allows only one channel of information through for full semantic processing while blocking other channels. This explained the dichotic listening findings of Cherry: when different messages are presented to each ear, people can attend to one and largely ignore the other, retaining only physical (not semantic) characteristics of the unattended message.
While Broadbent's early filter theory was modified by subsequent research (Treisman's attenuation model, Deutsch and Deutsch's late selection model), its importance lies less in its specific claims than in its approach. It was one of the first models to use the information-processing framework — flowchart diagrams showing how information flows through a series of processing stages — that became the dominant theoretical language of cognitive psychology. Broadbent also made important contributions to applied psychology, studying the effects of noise, heat, and fatigue on human performance in industrial settings.