help from research assistants like larry perlman, who took a job working on the twin study as a young they didn't believe that the infants would register the separation, would register the knowledge that they had a twin in the first few months. >> based on what? >> well, it was -- it was speculation, because nobody had studied infants. >> reporter: lori shineski informed reunited twins doug and howard that perlman had studied them in their separate adoptive homes when they were just 6 years old. more than 40 years later, the twins visited him at his home. >> hi. >> hi. how are you doing? >> howard. >> larry. >> doug. >> nice to meet you. >> it's been awhile, huh? >> yeah. 44 years. exactly. >> we were 6 when you -- >> yes. yes. i actually pulled out the testing that i did on you guys when you were exactly 6. so, i note that there were ten twins at that time. >> t sets? >> ten altogether. five sets. >> he has to research, he has a job, but for the people that were in it -- >> that's their life. >> it's, you know, people making decisions about your life, and you have no control over som