And his health problems didn't end there. In the last 20 years, he's suffered seizures, multiple infections and two bouts of cancer, reports Correspondent Morley Safer.
Through it all, Hellion has been at side, a constant helper and companion. What makes that relationship so special is not just because it's between man and an animal - in this case, a capuchin monkey trained to do some remarkable tasks. It's because it's a relationship of necessity.
Safer first met Foster and Hellion in 1981, not long after Hellion came to live with Foster as an experiment.
Foster used punishment and reward to modify Hellion's behavior, a practice fairly standard then for circuses and shows. When Hellion did well, she was rewarded with a pellet of monkey chow that Foster released though his chin controls. When she misbehaved, she got a blip of sound through the battery pack, and then a slight shock to her tail. It didn't take long before the conditioning made the shock unnecessary.
Hellion started out in life as a lab monkey in a series of behavior modification tests being conducted by a team at Tufts University.
"It's not a problem teaching them tasks," Willard told Safer in 1981. "You really can do that pretty rapidly, and we're standardizing things so that we can, in the space of a few months, teach a dozen different tasks. The problem is, can you control them and make them civilized? Can they live in an apartment setting and be happy without destroying it? And I think we're getting to the point where we can say yes to that also."
Modest grants from the Paralyzed Veterans of Americ and the National Science Foundation soon enabled other monkeys to be trained for similar assignments in a program called Helping Hands.
And what do the monkeys get out of it?
"Well, the things that make most people happy," says Willard. "Are you physically active? Do you have good food? Are you physically healthy? Do you have affection and love? Are you stimulated?"
Hellion has matured and slowed down in the last two decades, Foster says. "She's been very good and happy throughout the years. Good company."
When Foster requires hospitalization, his first priority is making sure that Hellion is cared for : "I mean, she's my child. I want her safe if I gotta go somewhere."
The person who helps make sure Hellion is safe, is Judi Zazula. An occupational therapist, who 25 years ago heard about Helping Hands, she offered her services and began training Hellion. Since then, she's trained most of the monkeys that have passed through Helping Hands. She's now the executive director.
Today, Helping Hands has 70 monkeys in homes all over the United States. It places 12 monkeys each year with the disabled. While the training is still very simple - monkey see, monkey do. – any sort of aversive training, electric shock or other punishment, is gone.
Gone, too, is the government funding. Once the experiment proved itself, the funding stopped. Now Helping Hands exists on private donations. As for getting the monkeys, it's much more organized than it was 20 years ago.
Helping Hands monkeys are bred in a colony at Southwick Zoo in the Boston area. From there, potential candidates go directly to foster homes where they spend the first six years of their lives, going through the familiar process of just being a kid.
"One thing that we've learned is that when monkeys are raised in a home environment as part of a human family, just like any child is, that this is the only life that they've ever known, then this is the life that they're comfortable in," says Zazula.
" We also know that monkeys have a life span of 30 to 40 years. So they have a long childhood. And they need to be little monkeys when they're little monkeys.
By the time new recruits reach Helping Hands for two years of schooling, which now is done solely with affection, repetition and persistence, they're twice the age Hellion was when she started.
"That's a big difference from Hellion's training and Hellion's history," says Zazula. "When Hellion was originally filmed for 60 Minutes, she was a very young toddler. And a lot of her activity level and a lot of her monkeyshines really were just a toddler being a little kid."
Hellion is 24 now, beginning to show the signs of old age. She's a little slower on the uptake, a little cranky and, just like some people we know, she's not crazy about change.
A few years ago, Foster got back a ittle bit of movement in his hand, and it bothers Hellion.
"Most of the time, I'm stuck in the chair, and I'm not moving," he says, "And all of a sudden, I'll be moving something. It startles her. She sees everybody else walking in. They can move and there's no problem. But for me, she's used to seeing me in the chair."
The affection berween the two is obvious, and Zazula says she believes Hellion has helped keep Foster alive.
"A number of times that Robert's been in the hospital and things really did look darkest for him," she says, "I would bring Hellion in. And just in curling up next to him in his bed, I knew that that was the thing that made him feel needed and loved and - and feeling like somebody mattered to him enough to come out of this."
July 2002 Update
Things did look dark once again for Robert last May. He had a seizure and was in a coma for several days, but once again he rallied. His first question: who's taking care of Hellion?
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