It is well known that the presentation order of choice options often affects decision outcomes to a significant degree. However, despite the significance and wide occurrence of the effects, they are ignored in most preference models. Furthermore, psychophysical findings of stimulus-magnitude dependent presentation-order effects have not been acknowledged previously in the cognitive literature on preference judgments. Thus, the potential moderating effect of the level of stimulus magnitude (here, valence) on the direction and size of order effects in preference judgment has not been investigated previously. In two experiments, participants (117 and 204, respectively) rated their preference for pairs of everyday-type objects and phenomena (e.g., apple–pear, headache–stomachache). Stimuli were spaced horizontally, and each participant received them in one of two opposite within-pair presentation orders. Participants also rated the stimuli's valence on a scale from very bad to very good. The results showed a positive correlation between the rated valence and the tendency to prefer the first-mentioned (left) stimulus; that is, the effect was greatest, and opposite, for choices between the most attractive and the most unattractive options, respectively. In terms of Hellström's (1979) sensation-weighting model, the positive correlation is caused by a higher weight (i.e., impact on the preference judgment) for the left stimulus than for the right, which is possibly due to the left stimulus being compared to the right. The results suggest that researchers may have failed previously to find important moderators of presentation-order effects in preference judgment due to the failure to use sufficiently attractive or unattractive stimuli. Copyright © 2010 John Wiley & Sons, Ltd.