Positive—Negative Asymmetry in Evaluation of Natural Stimuli: Empirical Study in the Contrast Model of Similarity Extended to Open Sets

Abstract

Abstract The current work shows empirical verification of the similarity theory extended to open sets of features, which states that an increase in similarity between 2 objects results from the deletion of distinctive features or the addition of common features, albeit with different effects. To date, theoretical simulations and empirical demonstrations using real features have shown how the model works. However, to test the validity of the model we conducted an experiment where direct judgments were used. A total of 188 participants were evaluated at 3 different levels related to similarity, affect, and willingness to live, in reference to cities that differed in terms of their amounts of positive and negative features. The results revealed that when their initial similarity to the ideal was greater than 0.5, deletion of distinctive, negative features had a stronger effect on the object evaluation and was more effective than adding positive features of the same value. When the initial similarity to the ideal was less than 0.5, opposite results were obtained; that is, the addition of common, positive features had a stronger effect on the object evaluation than deleting negative features of the same value. The results have shown a positive-negative asymmetry in the evaluation process, which supports the similarity theory extended to open sets of features. In addition, the findings revealed that the positive-negative asymmetry derived from the theory can be explained by the ratio difference principle.