Just a normal day in central park. So, what would make people act like this? Ahh! Reporter: It's a "would you fall for that" day of bird watching. All right, now, three-part challenge for scott. First... See More
Just a normal day in central park. So, what would make people act like this? Ahh! Reporter: It's a "would you fall for that" day of bird watching. All right, now, three-part challenge for scott. First of all, you have to persuade people you are a bird watcher. I don't know anything about birds, but okay. Reporter: Second, convince them you spotted a rare bird in central park. That's going to be hard. Reporter: Gets harder. You have to persuade people to gradually do more and more outlandish things to help you coax that bird out of the tree. Make them sing like a bird. All right, I'm up for the challenge. Now I just have to find an exotic bird that will go along with it. Reporter: First of all, scott needs a dead bird. From this dead bird store. I need a bird that's really going to pop. What do you think? Okay, this is an australian bird, spectacularly colored finch. Nice father's day gift, right? Lovely father's day gift. Good luck. Reporter: All right, so, scott is dressed as he thinks a bird watcher might dress. That looks good. I believe it. Rare bird alert. Give it a go. Reporter: It's a rare bird, never, ever, ever spotted alive in the u.S. Ever. Excuse me. I see an extremely rare bird. They are never seen here. This one got lost on the way to australia. Reporter: Scott is getting down to business and he's mixing up his back story, just for fun. I drove for 12 hours overnight. From ohio. From kentucky. Reporter: Nice touch, scott. For this social experiment to work, my bearded friend, who has never before looked through a pair of binoculars, needs to convince people he really is a semiprofessional. I think I found it. Yes. Congratulations. Reporter: It's lost. It's thousands of miles from home. You see it? I can't believe it. Random strangers are stopping and buying scott's story. They never come to new york. This is the first time. Reporter: Okay, now for the real social science. How far will a total stranger go to help scott snap a great photo of the uber-rare finch. Can you shake this for me? Reporter: Will they shake -- I brought all these things. Can you try this? Reporter: Will they put on a weird sweaty mask? He's a predator. Might turn his head. Reporter: Yes. Are you good at making calls? Reporter: Will they make weird noises? High c? Reporter: Yes! Will they dance? Yes! But why? Sitting at home, I bet you're saying, I would never fall for that, and that may be true. Going to be on the front page tomorrow. Reporter: Some people didn't. Is this like a hidden camera thing? You're not going to help me? Reporter: Science says a lot of people will fall for it. I took a lot of melds. No sleep. That's the one. Yeah. Reporter: They're helping him out. He's a nice guy. They're doing what he asks. Yep. They're even doing that. And the key here is something called foot in the door theory. It's a gradual process. You don't ask for everything all at once. First, scott has to win people's trust. And then ask them to perform simple tasks, one by one, until they are in too deep. Do you speak english? Yes. I think I see an extremely rare bird. He's a birder. Reporter: These guys are bird watchers. I'm trying to get a picture. Reporter: Oh, my goodness. Surely they will see through scott and his feathering facade. I drove here all night. I used to chase birds like that. Reporter: He may have chased birds, but definitely not like this. I brought all these supplies here. I'm using the worms to attract the bird. If you put it in your mouth, if you move around like this -- and, might turn -- what can I do to help? Put the worm in your mouth like that? Reporter: Here comes the sweaty bird mask. I want it to move its head so I can get a good shot of it. Can you put this own? Yeah. Reporter: Time to get a little ridiculous. How about some body language? Can you display a little bit? Going to get an award for this, I think. You mind putting the beak on? What? With the mask. You are a riot. I researched. I know -- we know, we understanding birding. Reporter: Wait, she understands birding? Oh, I ate the worm. Oh. Reporter: So, she takes another gummy worm. It's quite still. Reporter: And now, the big test. Will she put on the feathered headdress or will she finally say enough is enough? This is dress from australia. Reporter: We actually made it out of cheap feathers and glue. Put it on my shoulders if you want. Reporter: What? She's letting him put that thing on her? What is she thinking? I heard he was blown offtrack in migration -- there's one in captivity in the zoo in new jersey. Reporter: It's a gradual process this foot in the door and scott gets his whole leg in the door. He has gradually transformed joyce, a bird watcher, from this -- into this. You can't believe it? I can't believe you found it. I can't believe that you guys are on an abc tv show called "would you fall for that" right now. I did! Reporter: And what we've learned here? You want someone to do something big, big ridiculous, remember -- foot in the door. That's actually a fake bird in the tree. A dead bird. Cameras right over here. Reporter: Don't ask for the headdress straight out of the gate. You've got to start small. What do you think?
This transcript has been automatically generated and may not be 100% accurate.