For Questions Use the Following Narrative

For Questions use the following narrative
Narrative: Toy colors
Suppose a toy company wants to know if certain colors are more appealing and attractive to toddlers than others.They decide to measure this by choosing five colors of blocks and making sets of blocks in each of the five colors.Then they found 30 toddlers to participate in the study, and they randomly assigned each toddler a block color.They observed each toddler separately at the same time of the day, and gave them no other toys to play with.They recorded the length of time each toddler played with the blocks, to see if some colors of blocks were played with longer than other colors.All toddlers in the experiment were the same age (2 years old) and an equal number of girls and boys played with each color of blocks.
-{Toy colors narrative} Name one confounding variable that was controlled for in this study.