Stroop and Garner effects in and out of Posner's beam: reconciling two conceptions of selective attention.

Space- or object-based models, on the one hand, and structural-informational models, on the other hand, reflect conceptually distinct approaches to visual selective attention. In 3 studies, the authors contrasted these approaches by jointly applying prototypical routines prescribed in each approach. Following a space-based paradigm developed by M. I. Posner, participants were cued to attend to a certain spatial location, and performance at expected and unexpected locations was compared. Following a structural paradigm developed by W. R. Garner, the targets were color words printed in various colors, and the participants responded to either the color or the word component of the stimulus. Performance was poorer at unexpected than at expected locations. However, comparable amounts of Stroop and Garner interference affected performance at both expected and unexpected locations. It is suggested that the processes that govern (a) input selection from the visual field and (b) dimensional selection from the stimulus reflect fundamentally different systems of attention.