The people who consistently passed by Alexis seemed to assume that nothing was wrong. But experts said a lost child often masks distress.
"Unfortunately, what tends to happen in the real world is exactly what your actors did in this scenario," child advocate Allen said. "Young children aren't going to ask for help. They just stand there, and that's why we as adults really need to pay attention."
As the experiment continued with Alexis, nearly 10 minutes passed and dozens of people walked by the young actor. She looked confused and sad, but it was not until she began to cry that someone finally stopped and took action.
"You lost your Mom? In the store? Ok, I'll help you. No problem," one woman said.
Allen said many adults possibly didn't want to get involved with the lost child because of the "diffusion of responsibility" rule, which says that someone else will take care of the problem. "I do think there are those who see kids in vulnerable situations like that and think, 'Oh, I don't want to get involved. Somebody else will take care of this,'" Allen said.
Passerby Andrew Lazaroff agreed, saying, "People just don't know what to do. So after a moment of contemplation, maybe, they're just, 'I got to get to work. Somebody else will deal with it,'" he said.
But would gender make a difference in how people respond? Would more people stop if the "lost" kids were boys?
ABC News sent Robert out on the street to find out.
Once again, many people passed him. Some were reading books, and others just walked on by. We asked a few of these people why they didn't stop. "I figured since I was gonna walk back by again, if he was still by himself, I was gonna ask him if he was okay," Erin Kelly said.
Other people had different reasons for not stopping. "There were a lot of people around so I figured his mom was right there nearby," Angie Karpowicz said. "I actually thought he was throwing a fit or crying because of that."
The scenario played out again and again. In fact, it took more than 20 minutes before anyone noticed Robert was lost and came to his rescue: That's four times longer than it took for strangers to come to the aid of our girl actors.
The next actor, Eyalan, received a similar response. Again and again no one stopped. Many people looked, but then they kept right on walking.
After Annette Pasquale passed by Eyalan without coming to his aid she said, "I thought his parents may be in McDonald's. But I would have liked to have stopped, and I didn't."
In retrospect she agreed that she "absolutely" should have gotten involved.
Said Allen, the child advocate: "The reality is I think we as a culture, we as a society, view girls as more in need of our protection. We tend to think of boys as more rugged, more able to take care of themselves. But the reality is more boys are lost than girls; 55 percent are boys, 45 percent are girls."
We asked Allen what to do in the event that you actually do find a lost child. "The first challenge in a situation like this is to reassure the child that they're gonna be okay," he said.
Of all the people who didn't stop, there were some exceptional people who did stop to help our lost kids, "I'm Christina. Listen, I just want you to know, you're doing the right thing. You're not supposed to talk to strangers. They told you that right? I am a stranger and I should call the police … because I don't want you to be scared," she said.