Abstract
The purpouse of this study is to examine expenmentaly the relationship between belief formation and observed frequency of object-attribute link. In experiment stimulus frequency enough to form the belief which is called “threshold of confident response” was measured.
Subjects were instructed to infer whether certain box included only white stones by observing the drawing stones in turn. The value of threshold of confident response was sufficient number of stones for inferential judgement.
Two experimental conditions were distinguished. In Constant condition the number of stones in box was constant and subjects knew that number On the other hand, the stone number was variant and unknowable in Variant condition. Constant condition further divided into three conditions: Constant 10, Constant 20 (same Ss; 153) and Cornstant 30 (Ss; 62). Variant condition was held twice for different subjects (Variant I; 64 Ss, Variant II; 255 Ss).
The major findings were as follows:
(1) Threshold of confident response in constant condition bore a close resemblance to half of stone number contained in box.
(2) Threshold of confident response in Variant I and Variant II was 6.571 and 8.717 respectively, and this difference was significant statistically, But these two values were both higher than Constant 10 and lower than Constant 20.
(3) Threshold of confident response was distributed normally.
(4) Threshold of confident response was subject to wide fluctuations in each trial.
(5) Threshold of confident response showed individual difference.
These findings indicated that fixed amount of prior observations were required to form the inferential belief and that it was efficient to use the conception of threshold for explanation. Futher, it was suggested tha there were two types of threshold, relative threshold and absolute threshold. Finally, logistic curve was proposed as theoretical model that well fit the confident response of the middle term.
