The influence of trial-to-trial recalibration on sequential effects in cross-modality matching.

Sequential effects are examined in a cross-modality matching experiment where observers adjusted the loudness of a tone in response to presented lengths of a metal tape. In one condition, the initial level of the tone to be adjusted was the same as the final adjusted level of the previous trial, whereas in another condition, the tone to be adjusted was reset to a different level before each trial. A fit of the DeCarlo-Cross dynamic model shows that the primary effect of the manipulation was on a judgmental factor, with little or no effect on a perceptual factor. We suggest that starting a trial with the tone at the final adjusted level of the previous trial induced the observer to rely more heavily on the loudness-length pair of the previous trial as a frame of reference for relative judgment; we call this reliance trial-to-trial recalibration. In contrast, when the tone is set to a level independent of its value on the previous trial, there is virtually no effect of one trial on the next trial's performance, a result consistent with the observer maintaining a stable frame of reference. We argue that sequential effects are not unavoidable and that the technique described here adds to a growing list of methods for reducing or eliminating them.