Abstract
The purpose of the present study is to examined developmental changes and sex differences in judging weights. Experimental groups were engaged in weights addition tasks and then given correct answers (correctional feedback). Four to six months later, both experimental and control groups were subjected to the same tasks. The individual range of reaction time in 6th graders is much wider than that in 5th graders and that the presentation of correctional feedback is more effective in 6th graders. These results suggest that 6th graders make more efforts in judging weights addition with logical and overall criteria. Both 6th male and 5th female students judge weight with more consistent confidence than both 5th male and 6th female students. These results suggest that male students come to judge weight with consistent confidence with age while female students do not, and that the social desirability, that is, “male will always hold their own opinion” seems to affect judging process.
