Passage Summary: Toddlers have a hard time switching between different rules because the part of the brain that handles that task isn't fully developed until they are much older.

Reasoning: Toddlers can sort by shape but struggle to switch to sorting by color; this is linked to the prefrontal cortex, which is slow to mature and essential for rule-switching.

Analysis: Since we are treating these premises as facts, we need to find a conclusion that is logically forced by them. We know the prefrontal cortex is 'essential' for adapting to new rules and that it continues to develop into adolescence. This strongly suggests that as the cortex matures, the ability to switch rules should improve. Look for an answer that suggests older children or adolescents would likely perform better on these rule-switching tasks than the toddlers in the study did.