Perceptual and conceptual masking of pictures.

We report an experiment in which target pictures, presented for 50 ms, were followed by masks. Two mask variables were implemented: mask luminance and amount of attention demanded by the mask. Luminance but not attention demand affected subsequent picture-memory performance when the mask followed the picture immediately; however, attention demand but not luminance affected performance when the mask was delayed by 300 ms following the offset of the picture. We conclude that qualitatively different processes are being carried out at 0 versus 300 ms following the offset of a 50-ms picture. We argue that these processes can profitably be viewed as perceptual processes, which operate on raw stimulus input, and conceptual processes, which operate on the output of perceptual processes.