Susan Bennett-Armistead is an expert in child development at Michigan State University. She says seven is a tricky age because many children are just starting to realize the difference between what's real and what's fantasy.
Seven-year-olds can dress and feed themselves, but they don't understand the concept of money or how much food costs. They also live in the moment, and if a child is going away he or she most likely won't plan to pack for the days.
Officials think Holland did pack fruit snacks, but he's not a typical seven-year-old. He has ADHD and bipolar disorder. Experts say there's no telling how those conditions will affect his ability to live on his own.
Bennett-Armistead says children of this age depend on experiences for learning so if Holland has learned from previous experiences running away, he may be more capable to take care of himself than other children his age.
Another factor affecting seven-year-olds is their sense of adventure. Experts say Holland may have just been curious and that could be what's lead to his disappearance.