摘要：AbstractResearch with primary school children indicates while younger children believe a light ball will roll down an incline faster than a heavy ball – matching their beliefs about horizontal motion – older children believe the heavy ball will roll down faster – matching their conceptions about fall. The present research evaluated why this age shift occurs. Two studies were carried out with children aged 5-11. Study 1 (N= 210) investigated the subjectivity of predictions by addressing age-related changes in disparity between a heavy and a light ball. The study indicates predictions about fall are relatively stable across age groups but both horizontal and incline motion predictions change with age, suggesting the horizontal element in incline motion reasoning loses salience. Study 2 (N= 144) examined the role of the incline height in predictions. The results show the incline height at which both balls are predicted to have the same speed reduces with increasing age, suggesting an increased salience of the vertical element in incline motion reasoning. Together, both studies illustrate while horizontal motion and fall are reasoned about differently their importance in incline motion reasoning shifts with age, with the horizontal element's salience decreasing and the vertical's increasing.
