Effects of attention on perception of features and figural organisation.

Four studies are reported that demonstrate effects of attention on early perceptual processes. These studies show that directing attention to stimulus location influences perceived brightness, perceived length, and the overall organisation of the Müller-Lyer figure and ambiguous figures. Since in all four studies the dependent measure was dissociated from the attentional instructions, the results are not open to traditional criticism of late-selection advocates, and therefore provide strong support for early-selection views of attention.