Six experiments are reported which examine the young child's ability to compare included and nonincluded sets. Results indicate that with certain forms of task presentation most 3- to 5-year-old children can compare part with whole. Further, errors which occur in inclusion tasks are similar to errors which occur in tasks involving comparison of nonincluded sets. Thus young children can solve inclusion problems, and their customary failure to do so does not arise because the problem requires comparison of a whole with an included part. Employing a distinction between intended tasks (those which the adult wishes the child to complete) and received tasks (those which the child, in fact, completes) the studies indicate how linguistic and perceptual aspects of the presented information may interact with the child's assumptions about the nature of the task to be completed. © 1978.
McGarrigle, J., Grieve, R., & Hughes, M. (1978). Interpreting inclusion: A contribution to the study of the child’s cognitive and linguistic development. Journal of Experimental Child Psychology, 26(3), 528–550. https://doi.org/10.1016/0022-0965(78)90131-5