Why is it difficult to rectify a misconception in learners ?

Many people nourish a misconception that vacuums draw substance into them. But vacuums can never draw anything. In fact, air presses substance. This study aimed at investigating why it is difficult for learners to rectify such misconception, by using specially devised questions. Subjects were undergraduates. The main results were as follows ; (1) Once their misconception was provoked, most Ss unintentionally tried to modify their knowledge on the amount of air pressure in such a way as not to contradict their misconception. (2) Even when they were instructed in advance to use the relevant knowledge they had, their misconception couldn't be replaced by the correct concept. (3) But the reasoning process based on the relevant knowledge could be activated under a certain type of questions. (4) So we might infer that two contradictory reasoning processes could coexist in cognitive structure in learners.