[Sequence effects in absolute judgment? Critical comments on the method]

Several methods for demonstrating sequential effects in psychophysical judgments are discussed. None of them is free of problems. Simple simulations show that pseudosequential effects occur whenever some subjects judge the stimuli higher or lower than they should. Such effects may also be produced by response drifts during the course of an experiment. Breaks in the psychophysical function might be another source of pseudosequential effects. Contrary to a wide-spread opinion, it still remains to be shown that genuine sequence effects really exist.