Sequential relationships between Stroop color-word stimuli were explored in a random discrete-trials manual response design. Posttrial availability of an interfering response was indicated by a subsequent reduction of reaction time when that response became appropriate. Previous evidence for suppression of competing responses is probably artifactual. A second experiment indicated two sources of interference in the Stroop task: (a) the number of highly available competing responses and (b) the individual strength of each competing response. (Author)