The transformation of a solid to its net is based on something quite different from simple perceptual impression. It is a mental operation performed by manipulating mental images. The aim of this study was to observe pre-service and in-service teachers' ability to visualize the transformation of a curved solid to its net and vice versa, and to try…

The reversal errors in the printing of 51 first grade students were examined. These children were asked to print a series of reversible target figures (letters and numbers, such as 2-s, p-q, p-9, and b-d) that were presented alone and with their mirror-image counterparts. To control for the possibility that the mere presence of another figure…

The results of two experimental studies of interference in German-Swedish bilingual and trilingual high school students are presented. Both were developmental studies with length of residence in Sweden as the main independent variable. The purpose was to follow the developmental changes in intra- and interlingual interference and to find out if…