Infants of 8 1 2 and 9 1 2 mo of age were tested for the ability to "keep track," i.e., to determine the location of an object hidden in one of two covered containers before their left-right positions were reversed. Infants in both age groups for whom the covers were the same color and younger infants for whom the covers were different colors were generally unable to keep track. Only the older infants provided with different colored covers were able to do so. An analysis which separated keeping track from the sensorimotor stage 4 error indicated that (a) there was no contingency between the two and (b) there were developmental differences in the nature of the error. © 1981.
Goldfield, E. C., & Dickerson, D. J. (1981). Keeping track of locations during movement in 8- to 10-month-old infants. Journal of Experimental Child Psychology, 32(1), 48–64. https://doi.org/10.1016/0022-0965(81)90092-8