MIT model explains how the brain can learn novel tasks while still remembering what it has already learned.
An MIT professor who drifted in a dinghy after his boat capsized in the Pacific Ocean was rescued by a boat carrying another MIT employee who just happened to be cruising the same waters around the Galapagos Islands that day. Professor Thomas Sheridan and Dr. Peter Reich, chief of psychiatry at MIT Medical, met for the first time when the vacationing physician saw an emergency flare set off by the shipwrecked professor.
Said Professor Sheridan, who was one of 19 survivors of the June 10 accident, "My advice to people is to learn how to swim. It can come in handy. All the survivors were reasonably good swimmers."
The sun had just set when the calamity occurred. The air was mild and a light breeze blew. Professor Sheridan and his wife, Rachel, were on the deck of the Moby Dick -- a small cruise boat carrying them from one Pacific island to another -- when their adventurous vacation turned into a nightmare.
Although the weather was calm, large swells rocked the 70-foot boat from side to side, sometimes pushing it over at a pretty good pitch, then righting it, then tilting it to the other side. Dr. Sheridan, a semiretired professor of engineering and applied psychology in the Departments of Aeronautics and Astronautics and Mechanical Engineering, said he and the other 14 passengers weren't alarmed, since the night was tranquil.
"At one point, the boat went to its limit and sort of hesitated there," said Professor Sheridan, who stood at the bow of the boat at the time. "We all thought it would right itself."
But the boat capsized, took on water, and sank into the Pacific.
While the crew members cut loose lifesaving equipment, those passengers not tossed into the sea struggled to escape the sinking vessel.
"One woman was sick in her room, but managed to swim up the stairs and get out. Some were trapped by furniture. One went through a [broken] window," said Professor Sheridan. "Several people said later they had no idea how they got out."
ADRIFT AT SEA
Tom and Rachel Sheridan were thrown into the sea, where they found themselves sucked under the boat, trying to surface for air.
"We were bouncing along under the boat. We didn't know which way to swim. Fortunately it was moving pretty fast and passed over us," he said.
The Sheridans were lucky to find one another as soon as they resurfaced. They were also lucky to grab hold of a life raft, one of those cut free by the crew before the vessel sank. For about half an hour the couple clung to that lightweight raft, drifting on the dark sea. The water was warm, so hypothermia wasn't a fear, but the swells were so large they couldn't see around them.
At last they came across a dinghy with half a dozen other people in it, some crew from the sunken boat and some passengers. The Sheridans joined the group in the small boat. Later, several crew members on an inflatable raft tied up to the dinghy.
"The amazing thing is that people were pretty cool," Professor Sheridan said. "We'd all been together [on the cruise] for three days and the group had bonded pretty well. There was no hysteria." In fact, he said the Ecuadorian crew later remarked on the hardiness of this group of vacationing Americans, thrust into a disaster situation without warning.
Aboard the dinghy was a woman with a serious head wound. The top of her scalp had been sliced off, probably by the boat's propeller as it swept over her in the water. She lost a lot of blood but survived without brain injury. A New Hampshire man's arm was cut by the propeller in the same way. He had no idea where his wife was or whether she had survived, but he was a pharmacist and kept busy giving first aid to the injured woman.
"We were in good shape at this point. We probably could have lasted all night," said Profesor Sheridan.
Fortunately, they didn't have to.
The inflatable raft was equipped with a few emergency flares, which he helped set off when they spotted the lights of another boat in the distance. "A couple fizzled; some worked," he said. About half an hour after lighting the flares, they saw the lights of the other boat again. They appeared to be flashing.
"That's when we knew that they knew we were there," said Professor Sheridan. "It was an incredible experience to see those flashing lights. It looked like it was turning, going back and forth. We deduced that it was looking for -- and hopefully picking up -- other people along the way, which it was."
It took nearly an hour for the boat to reach the dinghy.
Dr. Peter Reich, chief of psychiatry at MIT Medical, happened to be standing at the bow end of the upper deck of a different boat plying those same waters in the Pacific. The seas were rough and he found that by holding onto the rail and keeping his eyes fixed on the horizon, he could enjoy the roller-coaster without getting seasick.
"The boat was tipping rather dramatically. It was kind of fun, although I had some concern about the height of the waves," said Dr. Reich. He and his wife, daughter, son-in-law, and his wife's sister and her husband were exploring the Galï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½pagos Islands on a trip very similar to the Sheridans', but run by a different tour group. They had seen the Moby Dick, a boat similar in size to theirs, as it left Isla Espaï¿½ï¿½ï¿½ola earlier that day.
"It was about 7pm. The sun sets early in the Galï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½pagos because it's near the equator. I saw up ahead of us this bright red light. I didn't know what it was, but the crew member at the wheel knew it was a distress signal," said Dr. Reich.
They traveled several miles to reach the site where the Moby Dick had capsized. As they approached, Dr. Reich and the others saw debris in the water. They also saw a floating light, a sign to the crew that a boat had gone down.
"When a boat sinks, there's apparently a radio that floats off the top of the boat up to the water's surface, broadcasting a Mayday and flashing a light. That signal was relayed by satellite and later picked up in Panama. We saw the light in the water.
"We were looking, searching. We heard cries for help, and with a flashlight beam saw the faces of people in a tippy little raft. Through a rather difficult maneuver, we managed to get alongside them without capsizing their raft," Dr. Reich said. By then, they had also located the dinghy containing the Sheridans, as well as the inflatable raft attached to it.
"We now had 19 people to rescue. It was very difficult in those high seas. One of our sailors leapt into the water with a ring and swam to them and one by one took them up. He climbed up the boat's tailgate and passed them up to us in the cabin, where we wrapped some of them in blankets and gave them water and food -- whatever they needed. My daughter is a pediatrician and she cared for the injured. Most were just badly shaken up.
"Of course there were lots of seasick people. The boat was tossing and tipping because the captain was holding it broadside to the waves so as not to capsize the dinghy. But this made it very rough. As you walked around the cabin, you could be thrown about and I was afraid there would be secondary injuries. It was pretty chaotic."
When all the survivors had been brought on board, it became obvious that some were missing. "They were in good spirits because they had been saved. But then, not everyone had been, and we had to deal with the emotional crisis," said Dr. Reich, who added that there were happy moments as well. "Two people had a reunion in the cabin. A woman who had already been rescued saw her husband climb up the back of the boat. She very emotionally cried out for joy."
"Eventually, because of the injured people, we were given clearance to leave the area. Ordinarily in this situation a boat would have to stay and search for other survivors," he said. Another boat, whose crew was making an IMAX film about the Galï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½pagos Islands, arrived to continue the search.
Looking back on the rescue, Dr. Reich said that when he first saw the debris he hadn't fully understood the implications. "Then we were busy rescuing people," he said. It was later, when he realized some people had not survived, that "it became distressing and horrifying. I thought 'Oh my God, that boat looks almost like ours. Maybe we could have capsized.'"
Dr. Reich also noted the remarkable composure of the people involved. "I was really impressed by Tom Sheridan's ability to stay calm and deal with this thing. I was impressed with all the survivors. They were not in shock -- not in any state -- when they came on board."
Although the two MIT employees had never met before, it didn't take long for Professor Sheridan and Dr. Reich to realize the MIT connection. "Somebody mentioned MIT and I said I worked there, and we started talking. I saw that Tom was okay except for a cut over his right eye. I asked if it needed attention, but he said it was minor," said Dr. Reich.
The group finally arrived at Isla Santa Cruz, their original destination, at about 2am, where they received medical care and lodging in the town of Puerto Ayora.
The disaster occurred on the third day of a week-long cruise planned by Elderhostel, a Boston-based organization that offers educational tours for people age 55 or older. The Moby Dick, a converted fishing boat, had left the small island of Isla Espaï¿½ï¿½ï¿½ola that afternoon on a course for Isla Santa Cruz. The boat carried seven crew members, a guide/interpreter and 15 American tourists.
The trip was to be an exploration of the Galï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½pagos Islands -- located about 600 miles off the Ecuadorian coast -- and their unusual species of flora and fauna, some of which exist nowhere else in the world. Charles Darwin made his study of finch beaks in this group of about 15 volcanic islands, eventually leading him to formulate the theory of evolution he explained in The Origin of Species but which is popularly known to many as 'survival of the fittest.'
While the Sheridans were forced to prove their mettle just to survive the trip, travel to the Galï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½ï¿½pagos isn't usually so demanding. Paul Barrett, who retired as director of MIT's Physical Plant in 1990, and his wife took an Elderhostel trip to the Islands in January 1996. He describes it as "a great trip" with no heavy seas, and plenty of time exploring the islands.
"The weather was very good. We'd spend every night on the boat and stop on the islands during the day. The crew would troll off the back of the boat and catch fish, which we'd have for dinner. We did a lot of snorkeling and swam with the young sea lions," he said, and went on to describe some of the unusual wildlife.
"The blue-footed boobies are quite odd-looking, and perfectly tame. When you walk on the islands, you have to stay on the trails for conservation reasons. Several times there was a blue-footed booby on the trail -- you know, just sitting on its nest. We'd have to go around it because it wouldn't move. All the animals were very tame. We saw iguanas, very large tortoises that are a hundred years old and little penguins."
NOT WHAT THEY HAD HOPED
While the Sheridans' experience would fit neatly into any 'explorers and adventurers' category, it didn't allow them to see as much of the islands as they had hoped. Professor Sheridan said they saw boobies -- grayish seabirds with bright blue or red feet -- and lounging sea lions on Isla Espaï¿½ï¿½ï¿½ola the morning of the accident. But he hopes to see more of the Islands another time, possibly even by the same route.
"After an accident like this, you almost have to feel that you're safer," he said. A disaster like the Moby Dick accident isn't likely to happen twice in the same way.
"The crew of our boat, the crew of the rescue boat, the travel agency, the Elderhostel people were all just absolutely super -- professional, caring and every good thing you can say. Of the 11 survivors, not one -- I don't think -- has a grudge against any of the people involved."
Oddly enough, it wasn't the first time Tom and Rachel Sheridan had capsized in a boat. Professor Sheridan said the first time he took his wife sailing, during their engagement, he capsized the small boat deliberately, "because for some reason I thought she ought to have that experience."
Four of the Moby Dick's passengers did not survive; only two of their bodies were recovered. One of the dead, the oldest of the travelers, was a man who, according to another of the survivors, chose to let go of a ring buoy to help ensure the survival of others clinging to the same lifesaving device. His wife, whom he had been unable to locate in the water, also died. The woman with the head injury lost her husband; his body was not recovered.
Professor Sheridan said that despite the severity of her injury, the wounded woman made it to a gathering of the survivors held on their last night in the islands. "The bonding between people in these circumstances is incredible," he said. At that gathering, the injured woman, who is not Jewish, offered a toast to her deceased husband, who was.
"L'chaim," she said in Hebrew. "To life."
A version of this article appeared in MIT Tech Talk on July 15, 1998.