Separate and combined effects of location cuing and repetition priming on perceptual encoding of words

We describe a methodology for investigating whether two manipulations exert independent effects on perception. This method avoids the strong scaling a ssumptions inherent to traditional analysis of variance techniques, and we used it to investigate the combined effects of cued visual attention and st imulus repetition. Subjects identified previously studied (primed) and new (unprimed) masked words that were presented to validly and invalidly cued l ocations for varying durations. Performance improved more rapidly with incr easing exposure duration for primed than for unprimed, and for attended tha n for unattended, stimuli. We interpret this finding as indicating that bot h variables speed the rate of information acquisition. The speedup provided by priming and attention combined equaled the product of benefits for each alone, providing evidence they are serial, independent effects.