NO FREQUENCY EFFECTS WHEN JUDGING CONTRASTS

  • Marco Tommasi
  • Elias Casula

Abstract

In literature, experimental findings showed that absolute judgments are affected by contextualeffects. In our experiment we tested if judgments of differences, in particular, judgments ofbrightness contrasts between two chips are affected by the skewing of frequency distributionsof stimulus presentations. We asked participants to rate the degree of contrast by using twomethods: the category rating method and the adjustment method. Experimental results showthat frequency effects do not affect contrast judgments and that there is no difference betweenthe subjective scales obtained with the two methods, except for the “regression effectâ€.Therefore, judgments of differences, contrarily to absolute judgments, are not affected bycontextual effects.
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