The Role Of Essential Features In Classification Of Biological Categories

The present study is to investigate the role of essential features in the classification and the regulating effect of the causal relationship between the features. Experiment One asked subjects to make classification judgment on the individual animals consisting essential and nonessential features. It was aimed to explore the role of different category features in classification. Experiment Two asked subjects to make essential features judgment classification sufficiency judgment and classification necessity judgment. It wanted to directly explore the role of essential and nonessential features in classification. For defects of previous experiments, in Experiment Three, subjects were asked to make classification judgment in the conditions with or without the hint about the causal relationship between the category features. In this way, researchers could explore the regulating effect of the causal relationship between the features.The results are summarized as follows. Firstly, compared with the nonessential features, family origin、gene system and internal structure’s scores of essential feature judgment、classification sufficiency judgment and classification necessity judgment were higher. It means that essential features had a greater role in classification. Secondly, compared with the family origin and internal structure feature, gene system’s scores of essential feature judgment、classification sufficiency judgment and classification necessity judgment were higher. So gene system feature had the greatest effect in classification and was the most essential feature. Thirdly, the difference between essential feature judgment and classification sufficiency judgment and the difference between essential feature judgment and classification necessity judgment were both not significant. The results of three judgments were consistent, so using classification sufficiency and necessity to represent the importance of category features in classification was reasonable. Fourthly, the presence or absence of the hints about causal relationship between the features affected the essential features’effects in classification. In the causal relationship producing condition and presenting causal relationship figure condition, the gene system’s classification weight declined, and the family origin’s classification weight improved. Fifthly, after giving subjects the causal relationship hints, all the three experimental effects of causal knowledge affecting classification(the causal status effect、the coherence effect、relational centrality effect) appeared, and the relational centrality was first discovered in adult subjects.The results indicate that both essential features and causal relationships between features play a role in the classification and can influence the results of classification.