Abstract
When do young children become able to make an adequate choice between two alternatives based on spatial information? Children of 20, 30, and 40 months of age were either presented with two objects with different cross-sections and one aperture, or one object and two different apertures. In each trial there was one object – aperture match and the task was to find that match and insert the object. All the children understood the task and tried to solve the problems but the 20-month-olds performed randomly and not even the 40-month-olds chose all the correct correspondences consistently. The results also showed that it is easier to choose between apertures than objects. This contrasts with the ability to solve the insertion problem once the choice was made. When choosing the correct object or aperture, the 40-month-olds inserted the triangle successfully in 85% of the cases. The boys and girls were equally good at solving the task, but the boys did it faster. The results show that making a choice adds significantly to the difficulty of solving spatial problems. It requires systematic examination of the objects and apertures involved, a working memory that can handle at least three items at a time, and an ability to inhibit an incorrect choice. Such executive functions are typically found in older preschool children but the present task shows that with an appropriate setup their development can be traced from a much earlier age.
Acknowledgments
The research was supported by grants to CvH from The Swedish Research Council, and EU integrated project FP6 – 004370 (Robotcub).
We would like to thank Pär Nyström for having constructed and maintained the program used for analysing videos. We would also like to thank our fantastic baby lab for helpful comments in a warm and friendly atmosphere. Last but not least we thank the families for their enthusiastic participation in this study.