THE EFFECT OF SPATIAL ATTENTION ON MEMORY SCANNING

Participants responded to probe letters after sets of two, four, and s ix letters were memorized (Sternberg, 1966, 1969b). Spatial attention was controlled by central arrow cues and stimuli were presented in a c lear or a visually degraded form. Overall RT was shorter for attended than for unattended locations, and shorter for clear than for degraded stimuli. Even though the function relating RT to memory-set size for stimuli in attended locations had a significantly smaller zero-interce pt than the function for unattended locations, the slope was unchanged , which suggests that attention did not influence the memory-scanning stage. Visual quality interacted with attention, which suggests that t hey influenced the same stage of processing, presumably the early visu al-encoding stage of processing.